Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

A new phenacene-type molecule, [8] phenacene, which is an extended zigzag chain of coplanar fused benzene rings, has been synthesised for use in an organic field-effect transistor (FET). The molecule consists of a phenacene core of eight benzene rings, which has a lengthy pi-conjugated system. The structure was verified by elemental analysis, solid-state NMR, X-ray diffraction (XRD) pattern, absorption spectrum and photoelectron yield spectroscopy (PYS). This type of molecule is quite interesting, not only as pure chemistry but also for its potential electronics applications. Here we report the physical properties of [8] phenacene and its FET application. An [8] phenacene thin-film FET fabricated with an SiO2 gate dielectric showed clear p-channel characteristics. The highest m achieved in an [8] phenacene thin-film FET with an SiO2 gate dielectric is 1.74 cm(2) V-1 s(-1), demonstrating excellent FET characteristics; the average mu was evaluated as 1.2(3) cm(2) V-1 s(-1). The mu value in the [8] phenacene electric-double-layer FET reached 16.4 cm(2) V-1 s(-1), which is the highest reported in EDL FETs based on phenacene-type molecules; the average m was evaluated as 8(5) cm(2) V-1 s(-1). The mu values recorded in this study show that [8] phenacene is a promising molecule for transistor applications.

DOI： 10.1038/srep05330

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Field-effect transistors (FETs) were fabricated with a thin film of 3,10-ditetradecylpicene, picene-(C14H29)(2), formed using either a thermal deposition or a deposition from solution (solution process). All FETs showed p-channel normally-off characteristics. The field-effect mobility, m, in a picene-(C14H29)(2) thin-film FET with PbZr0.52Ti0.48O3 (PZT) gate dielectric reached similar to 21 cm(2) V-1 s(-1), which is the highest mu value recorded for organic thin-film FETs; the averagem mu value (<mu >) evaluated from twelve FET devices was 14(4) cm(2)V(-1) s(-1). The, m. values for picene-(C14H29)(2) thin- film FETs with other gate dielectrics such as SiO2, Ta2O5, ZrO2 and HfO2 were greater than 5 cm(2) V-1 s(-1), and the lowest absolute threshold voltage, vertical bar V-th vertical bar, (5.2 V) was recorded with a PZT gate dielectric; the average jVthj for PZT gate dielectric is 7(1) V. The solution-processed picene-(C14H29)(2) FET was also fabricated with an SiO2 gate dielectric, yielding mu = 3.4 x 10(-2) cm(2) V-1 s(-1). These results verify the effectiveness of picene-(C14H29)(2) for electronics applications.

DOI： 10.1038/srep05048

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Fluorescence, fluorescence excitation and absorption spectra of picene have been measured in the vapor phase. It is shown that picene vapor exhibits weak fluorescence from the S-2(pi, pi*) state in addition to strong S-1(pi, pi*) fluorescence. The S-2/S-1 fluorescence yield ratio is evaluated to be approximately 1.3 x 10(-2) following the excitation into the S-3 state. It is shown that the relative S-2 fluorescence quantum yield increases with increasing excitation energy, while the S-1 fluorescence yield is nearly invariant. Mechanism of the appearance of the S-2 fluorescence of picene vapor is discussed. (c) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2013.03.055

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Authorship：Lead author,　Corresponding author   Language：English   Publisher：SPRINGER  

Facile synthesis of fulminene ([6]phenacene) was achieved through the Mallory reaction of 1-(1-naphthyl)-2-(1-phenanthryl)ethene or the 9-fluorenone-sensitized photo-ring-closure of 1-(1-naphthyl)-2-(1-phenanthryl)ethane. The electronic spectral properties of fulminene were investigated for the first time using photoluminescence as well as transient absorption spectroscopy. The spectral features were compared with those of a series of lower phenacene homologs such as phenanthrene ([3]phenacene), chrysene ([4]phenacene), and picene ([5]phenacene). For the [n]phenacene series, both the fluorescence and phosphorescence bands linearly red-shifted with an increase in the number of the benzene rings (n). Trends in the energy levels of the excited singlet (E (S)) and the triplet (E (T)) states were expressed as E (s) = -2.6n + 89.1 (kcal mol(-1)) and E (T) = -1.8n + 66.2 (kcal mol(-1)), respectively. In the case of fulminene, laser flash photolysis displayed a transient spectrum with an absorption maximum (lambda (max) (T-T) ) at 675 nm, which was assigned as the triplet fulminene excited state. The lambda (max) (T-T) values for the [n]phenacene series showed a linear correlation as a function of the ring number n, given by an equation, lambda (max) (T-T) = 60n + 318 (nm).

DOI： 10.1007/s11164-012-0639-1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Field-effect transistors (FETs) based on [6]phenacene thin films were fabricated with SiO2 and parylene gate dielectrics. These FET devices exhibit field-effect mobility in the saturation regime as high as 7.4 cm(2) V-1 s(-1), which is one of the highest reported values for organic thin-film FETs. The two- and four-probe mobilities in the linear regime display nearly similar values, suggesting negligible contact resistance at 300 K. FET characteristics were investigated using two-probe and four-probe measurement modes at 50-300 K. The two-probe mobility of the saturation regime can be explained by the multiple shallow trap and release model, while the intrinsic mobility obtained by the four-probe measurement in the linear regime is better explained by the phenomenon of transport with charge carrier scattering at low temperatures. The FET device fabricated with a parylene gate dielectric on polyethylene terephthalate possesses both transparency and flexibility, implying feasibility of practical application of [6] phenacene FETs in flexible/transparent electronics. N-channel FET characteristics were also achieved in the [6] phenacene thin-film FETs using metals that possess a small work function for use as source/drain electrodes.

DOI： 10.1039/c3cp53598c

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A facile formation of picene was achieved by photosensitization of 1,2-di(1-naphthyl)ethane using 9-fluorenone as a sensitizer. This sensitized photoreaction is the first photochemical cyclization of ethylene-bridged naphthalene moieties to afford the picene skeleton. 5,8-Dibromopicene, prepared by this procedure using 1,2-di[1-(4-bromonaphthyl)]ethane as the substrate, was readily converted to novel functionalized picenes by conventional substitution and cross-coupling reactions.

DOI： 10.1021/ol200874q

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Efforts to identify and develop new superconducting materials continue apace, motivated by both fundamental science and the prospects for application. For example, several new superconducting material systems have been developed in the recent past, including calcium-intercalated graphite compounds(1), boron-doped diamond(2) and-most prominently-iron arsenides such as LaO(1-x)F(x)FeAs (ref. 3). In the case of organic superconductors, however, no new material system with a high superconducting transition temperature (T(c)) has been discovered in the past decade. Here we report that intercalating an alkali metal into picene, a wide-bandgap semiconducting solid hydrocarbon, produces metallic behaviour and superconductivity. Solid potassium-intercalated picene (K(x)picene) shows T(c) values of 7K and 18 K, depending on the metal content. The drop of magnetization in Kxpicene solids at the transition temperature is sharp (<2 K), similar to the behaviour of Ca-intercalated graphite(1). The Tc of 18K is comparable to that of K-intercalated C(60) (ref. 4). This discovery of superconductivity in K(x)picene shows that organic hydrocarbons are promising candidates for improved T(c) values.

DOI： 10.1038/nature08859

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A field-effect transistor (FET) with thin films of picene has been fabricated on SiO(2) gate dielectric. The FET showed p-channel enhancement-type FET characteristics with the field-effect mobility, mu, of 1.1 cm(2) V(-1) s(-1) and the on-off ratio of >10(5). This excellent device performance was realized under atmospheric conditions. The p increased with an increase in temperature, and the FET performance was improved by exposure to air or O(2) for a long time. This result implies that this device is an air (O(2))-assisted FET. The FET characteristics are discussed on the basis of structural topography and the energy diagram of picene thin films.

DOI： 10.1021/ja803291a

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The title trifluoroacetylaminophthalimide derivative produced a violet fluorescence (lambda(FL)(max) 392 nm) in MeCN, and it displayed a green emission (lambda(FL)(max) 506 nm) after irradiation at 254 nm in the presence of iodide ions. The corresponding amidate ion of the trifluoroacetamide was identified as the green fluorescence emitter. The deprotonation reaction may be caused by proton-abstracting solvated electrons generated by a photochemical charge-transfer-to-solvent process from I(-) to MeCN.

DOI： 10.1021/ol801184x

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ja067350r

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The triplet-sensitized photoreactions of the title biplanophane system 6, the photoisomer of a 2,11diaza[3,31(9,10)anthracenoparacyclophane derivative 5, were investigated by stationary and laserflash photolyses using xanthone (XT) and benzophenone (BP) as triplet sensitizers. Vaen photoisomer 6 underwent XT-sensitized irradiation, a triplet cyclophane 5 and a novel polycyclic product 7 were obtained via an adiabatic cycloreversion and a formal [2pia + 2 pia + 2sigmas] rearrangement, respectively. The maximum quantum yield for the formation of cyclophane 5 (0.69) and the upper-limit efficiency for the formation of polycycle 7 (0.31) were determined by laser photolysis techniques. For BP-sensitized photolysis of photoisomer 6, oxetane 8, in addition to triplet cyclophane 5 and polycycle 7, was formed by a Paterno-Biichi reaction. The quenching rate constant (k(q)) of triplet BP by photoisomer 6 (3.4 x 10(8) dm(3) Mol(-1) s(-1)) was found to be 1 order of magnitude smaller than that for XT (5.0 x 10(9) dm(3) mol(-1) s(-1)). On the basis of the relationship between k(q) and the triplet donor-acceptor energy gap, the triplet energy level of photoisomer 6 was estimated to be similar to71 kcal mol(-1). The photochemical and the photophysical processes involved in the sensitized photolyses are summarized in an energetic reaction diagram and discussed in detail.

DOI： 10.1021/jo048757m

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/molecules29245941

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Progress toward single‐molecule electronics relies on a thorough understanding of local physico‐chemical processes and development of synthetic routines for controlled hetero‐coupling. We demonstrate a structurally unexpected ring closure process for a homo‐coupled 4,4’‐bipicenyl, realized in on‐surface synthesis. An initial covalent C−C coupling of 4‐bromopicene locks at lower temperatures the position and geometrically shields part of 4,4’‐bipicenyl. Employing this effect of shielding might offer a path toward controlled stepwise hetero‐coupling. At higher temperatures, a thermally activated three‐dimensional rotation upon hydrogen dissociation, a dehydrogenative roto‐cyclization, lifts the surface‐dimensionality restriction, and leads to the formation of a perylene. Thereby, the shielded molecular part becomes accessible again.

DOI： 10.1002/asia.202400620

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpcc.4c03476

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

[3₂](1,4)Naphthalenophanes, bearing carbon-bridge chains (syn- and anti-NPs) and nitrogen-bridge chains (syn- and anti-ANPs), were synthesized, and their X-ray structures and photoreactions were investigated. The intramolecular separation distance between the naphthalene cores for ANPs was shorter than that for NPs, suggesting that intramolecular interactions between the naphthalene rings  were more efficient for ANPs compared to NPs. Upon photoirradiation at 300 nm, anti-NP, syn-ANP and anti-ANP produced the corresponding intramolecular [π4s + π4s] cycloadducts, whereas syn-NP gave an unidentified complex product mixture. Quantum yields for the photo-consumption (Φ_PC) of NPs and ANPs were evaluated to quantitatively compare their photoreactivity. The Φ_PC values of ANPs were approximately two-fold higher than those of ANPs.Noteworthily, the Φ_PC value of syn-ANP was estimated to be unity. Based on these results we discuss the effects of the alignments of the naphthalene cores (antivs. syn) and the bridging elements (C-bridge vs. N-bridge) on the photoreaction efficiencies of [3₂](1,4)naphthalenophanes.

DOI： 10.1007/s43630-024-00610-w

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Other Link： https://link.springer.com/article/10.1007/s43630-024-00610-w/fulltext.html

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jphotochem.2024.115613

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpcc.3c06294

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jphotochem.2022.114387

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Imide-fused [n]phenacenes were synthesised and their fluorescence spectra were observed to reveal that they showed positive solvatofluorochromism due to intramolecular charge transfer from the phanacene π core to the imide moieties in the S₁ state.

DOI： 10.1039/d2ra07771j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpcc.2c04879

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The magnitude of the field-effect mobility mu of organic thin-film and single-crystal field-effect transistors (FETs) has been over-estimated in certain recent studies. These reports set alarm bells ringing in the research field of organic electronics. Herein, we report a precise evaluation of the mu values using the effective field-effect mobility, mu(eff), a new indicator that is recently designed to prevent the FET performance of thin-film and single-crystal FETs based on various phenacene molecules from being overestimated. The transfer curves of a range of FETs based on phenacene are carefully categorized on the basis of a previous report. The exact evaluation of the value of mu(eff) depends on the exact classification of each transfer curve. The transfer curves of all our phenacene FETs could be successfully classified based on the method indicated in the aforementioned report, which made it possible to evaluate the exact value of mu(eff) for each FET. The FET performance based on the values of mu(eff) obtained in this study is discussed in detail. In particular, the mu(eff) values of single-crystal FETs are almost consistent with the mu values that were reported previously, but the mu(eff) values of thin-film FETs were much lower than those previously reported for mu, owing to a high absolute threshold voltage, vertical bar V-th vertical bar. The increase in the field-effect mobility as a function of the number of benzene rings, which was previously demonstrated based on the mu values of single-crystal FETs with phenacene molecules, is well reproduced from the mu(eff) values. The FET performance is discussed based on the newly evaluated mu(eff) values, and the future prospects of using phenacene molecules in FET devices are demonstrated.

DOI： 10.1021/acsomega.1c06932

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Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

3-Decyl-10-phenyl[5]phenacene (PhC10-PIC) molecule shows good FET characteristics in case of using ZrO₂ gate dielectric, owing to strong fastener effect and large π-overlap.

DOI： 10.1039/d2tc03383f

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Heterocyclic Chemistry  

DOI： 10.3987/com-22-14703

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jphotochem.2021.113518

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>A ring oscillator consisting of p-channel and n-channel organic FETs.</p>

DOI： 10.1039/d1ra00511a

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Language：English   Publishing type：Research paper (scientific journal)  

© 2020 Elsevier B.V. We prepared various compounds having the N-methylaminoanthranyl (MANT) moiety tethered with oligomethylene chains, and investigated the photophysical features in solution and the solid state based on the fluorescence quantum yields and lifetimes, and quantum chemical calculation. The molar absorption coefficient and fluorescence quantum yield were enhanced by an increase of the number of the MANT chromophore, resulting in an increase of the brightness as emission probes. Solid-state blue emission at room temperature was observed with moderate fluorescence quantum yields. The fluorescence rates in the solid state were found to be similar those in solution. From the results of the transient absorption measurements, the photophysical deactivation pathways in the solution were discussed. The studied multi-MANT compounds could be applicable to emissive photonic crystals and an exciton generating source for blue-color OLED.

DOI： 10.1016/j.jphotochem.2020.112650

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>Picenediimide derivatives serve as the active layer of <italic>n</italic>-channel thin-film field-effect transistors displaying a maximum charge carrier mobility as high as 2.0 × 10⁻¹ cm² V⁻¹ s⁻¹.</p>

DOI： 10.1039/d0ra06629j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.orgel.2019.06.021

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.tetlet.2019.151189

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10847-018-00877-4

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Other Link： http://link.springer.com/article/10.1007/s10847-018-00877-4/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<p>
<italic>N</italic>,<italic>O</italic>-Coordinated BF₂ complexes (Ar@HCs) having aromatic (Ar) and heterocycle (HC) moieties were prepared, and their photophysical properties were investigated in solution and the solid state along with their crystal structures.</p>

DOI： 10.1039/c9pp00410f

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>The transport properties of 3,10-ditetradecylpicene ((C₁₄H₂₉)₂-picene) and [6]phenacene thin-film field-effect transistors (FETs) on Si and plastic substrates are reported, in which SiO₂ and parylene are used as gate dielectrics, respectively.</p>

DOI： 10.1039/c8tc05824e

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Publishing type：Part of collection (book)   Publisher：Springer Singapore  

DOI： 10.1007/978-981-13-3417-7_8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jphotochem.2018.04.017

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.tetlet.2018.02.033

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.tetlet.2017.12.049

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<p>2-Amino-1,8-naphthalimide showed blue fluorescence independent of the microenvironment of the solvents whereas the corresponding 3- and 4-amino derivatives displayed marked positive solvatofluorochromism.</p>

DOI： 10.1039/c8pp00302e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.inorgchem.7b02013

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/poc.3726

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG KG  

Various phenacenes possessing chrysene, picene, and fulminene frameworks were prepared by using a continuous-flow synthetic protocol in which Wittig reaction affording diarylethenes and their Mallory photocyclization producing phenacene skeletons were sequentially performed. The Wittig reaction solution, containing the diarylethene obtained from an arylaldehyde and an arylmethyltriphenylphosphonium salt, was mixed with an iodine solution in the flow system and, subsequently, the solution was subjected to the photoreaction. Desired phenacenes were obtained with high to moderate chemical yield. For the present protocol, isolation of the intermediary diarylethene, which is the key precursor of the phenacene, is unnecessary. The approach provides a convenient method to supply a variety of phenacene samples, which are needed for initial systematic surveys in material science.

DOI： 10.1055/s-0036-1588775

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpcc.7b01806

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We studied the photoproducts of 1-(n-phenanthryl)-2-(m-phenanthryl) ethenes (nEm; n, m = 1, 3 and 9) for understanding photocyclization patterns based on NMR spectroscopy. The crystal structures of the photoproducts were analyzed by X-ray crystallography, and the photophysical features of the photocyclized molecules were investigated based on emission and transient absorption measurements. Phenanthrene derivatives substituted at the 1-and 3-positions were prepared for synthesizing nEm by photocyclization of stilbene derivatives. We obtained four types of primary photoproducts (n@ m) from the corresponding nEm. Two of them were found to have racemic molecular structures in the single crystal determined by X-ray crystallography. Besides the primary photoproducts, two types of secondary photoproducts (n@mPP) were isolated. Fluorescence quantum yields and lifetimes of the obtained photoproducts were determined in solution whereas the definite fluorescence quantum yields were obtained in the powder. Observation of the triplet-triplet absorption spectra in solution by laser photolysis techniques showed that intersystem crossing to the triplet state competes with the fluorescence process.

DOI： 10.1039/c7pp00040e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We prepared a variety of coumarin derivatives having expanded pi-electron systems along the direction crossing the C-3-C-4 bond of the coumarin skeleton via a photochemical cyclization process and investigated their photophysical features as a function of the number (n) of the added benzene rings based on emission and transient absorption measurements. Upon increasing n, the fluorescence quantum yields of the pi-extended coumarins increased. Expanding the p-electron system on the C-3-C-4 bond of the coumarin skeleton was found to be efficient for increasing the fluorescence ability more than that on the C-7-C-8 bond. Introducing the methoxy group at the 7-position was also efficient for enhancing the fluorescence quantum yield and rate of the expanded coumarins. The non-radiative process from the fluorescence state was not substantially influenced by the expanded pi-electron system. The competitive process with the fluorescence was found to be intersystem crossing to the triplet state based on the observations of the triplet-triplet absorption. The effects of the expanded pi-electron systems on the fluorescence ability were investigated with the aid of TD-DFT calculations.

DOI： 10.1039/c6pp00399k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Potassium-doped picene (K(3.0)picene) with a superconducting transition temperature (TC) as high as 14 K at ambient pressure has been prepared using an annealing technique. The shielding fraction of this sample was 5.4% at 0 GPa. The TC showed a positive pressure-dependence and reached 19 K at 1.13 GPa. The shielding fraction also reached 18.5%. To investigate the chemical composition and the state of the picene skeleton in the superconducting sample, we used energy-dispersive x-ray (EDX) spectroscopy, MALDI-time-of-flight (MALDI-TOF) mass spectroscopy and x-ray diffraction (XRD). Both EDX and MALDI-TOF indicated no contamination with materials other than K-doped picene or K-doped picene fragments, and supported the preservation of the picene skeleton. However, it was also found that a magnetic K-doped picene sample consisted mainly of picene fragments or K-doped picene fragments. Thus, removal of the component contributing the magnetic quality to a superconducting sample should enhance the volume fraction.

DOI： 10.1088/0953-8984/28/44/444001

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP Publishing  

DOI： 10.1088/0953-8984/28/33/334001

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Other Link： http://stacks.iop.org/0953-8984/28/i=33/a=334001?key=crossref.cedda9374837be0f2e3c82a674e5a7ac

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Difluoroboronate beta-diketones, compounds 1 having the fluorene moiety and the phenyl groups as well as the ligating precursors of the corresponding beta-diketones, compounds 2 were synthesized. The photophysical features of compounds 1 were investigated based on the measurements of fluorescence yields and lifetimes, and transient absorption. Compounds 1 are significantly fluorescent with quantum yields of ca. 0.95 in acetonitrile and ca. 0.90 in chloroform. Fluorescence from compounds 1 was observed also in the solid state. Observation of extremely weak triplet-triplet absorption spectra of compounds I verifies the large fluorescence quantum yields. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2016.03.011

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

the widespread interest in the chemistry, physics and materials science of such molecules and their potential applications. In particular, extended phenacene molecules, consisting of coplanar fused benzene rings in a repeating W-shaped pattern have attracted much attention because field-effect transistors (FETs) using phenacene molecules show promisingly high performance. Until now, the most extended phenacene molecule available for transistors was [8] phenacene, with eight benzene rings, which showed very high FET performance. Here, we report the synthesis of a more extended phenacene molecule, [9] phenacene, with nine benzene rings. Our synthesis produced enough [9] phenacene to allow the characterization of its crystal and electronic structures, as well as the fabrication of FETs using thin-film and single-crystal [9] phenacene. The latter showed a field-effect mobility as high as 18 cm(2) V-1 s(-1), which is the highest mobility realized so far in organic single-crystal FETs.

DOI： 10.1038/srep21008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We investigated the photophysical properties of difluoroboronated beta-diketones (BF2DK) with chrysene and pyrene skeletons (ChB and PyB, respectively) in solution and in the solid state. Acetylchrysenes, as the key precursors to ChBs, were photochemically prepared from the corresponding (acetylphenyl) naphthylethenes by means of a modified photocyclization method. The absorption and emission spectra of the BF(2)DKs were obtained in chloroform and acetonitrile, and the quantum yields and lifetimes of the fluorescence were determined. Excimeric fluorescence from PyB was absent even in highly concentrated solution. Based on the Lippert-Mataga analysis of the absorption and fluorescence features, the photophysical properties of the ChBs were discussed in comparison with those of PyB. The fluorescence states of the studied BF(2)DKs are shown to be of a charge-transfer character. The fluorescence quantum yields decrease with increasing the solvent polarity due to the enhanced internal conversion process. The fluorescence quantum yields in the solid state of the studied BF(2)DKs were determined, and it was found that PyB is fluorescent, whereas the fluorescence quantum yields of the ChBs depend on the substituted position of the chrysene moiety.

DOI： 10.1039/c6pp00089d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Six difluoroboronated beta-diketones having the phenanthrene skeleton (Phe@Ar) are prepared. Based on the measurements of the fluorescence quantum yields, lifetimes and transient absorption, the photophysical features of Phe@Ar are studied in comparison with those of difluoroboronated diketones having phenyl, naphthyl and anthryl moieties. beta-Diketones having 1-, 2-, 3- and 9-phenanthryl moieties (PheDKAr) were prepared as the precursor to Phe@Ar. 1-Acetylphenanthrene was synthesized by the photocyclization method as the key building block of PheDKAr having the 1-phenanthryl moiety. The counter aromatic moieties (Ar) of the prepared PheDKAr are varied with phenyl, furyl and thienyl rings (Ar = Ph, F and T, respectively) to investigate the effects of p-conjugation on the fluorescence properties. The prepared Phe@Ars are fluorescent with appreciable fluorescence quantum yields which depend on the substitution position of the phenanthrene moiety. 3-Phe@Ph having the 3-phenanthryl moiety provides the largest fluorescence quantum yield (0.81) in acetonitrile among the Phe@Ars whereas 2-Phe@Ph having the 2-phenanthryl moiety shows the smallest fluorescence quantum yield (0.07) in acetonitrile. All the Phe@Ars show fluorescence also in the solid state, and the fluorescence spectra and quantum yields were determined. Transient absorption measurement using laser flash photolysis of the Phe@Ars revealed the triplet formation. DFT and TD-DFT calculations of Phe@Ars rationalize the dependency of the fluorescence quantum yields on the substitution position of the phenanthrene skeleton in terms of difference in the oscillator strength for the HOMO-LUMO transition.

DOI： 10.1039/c5pp00454c

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

DOI： 10.11316/jpsgaiyo.71.1.0_1851

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Photophysical and photochemical features of [3n]cyclophanes (3nCPs) (n = 2-6) in solution were investigated by emission and transient absorption measurements. The studied 3nCPs show excimer fluorescence without locally excited fluorescence whereas some of them emit excimer phosphorescence in rigid glass at 77 K. The probability of excimeric phosphorescence from transannular pi-electron systems was shown to strictly depend on the symmetric molecular structures. A feature of intersystem crossing from an excimeric fluorescence state to the excimeric triplet state was observed. Transient absorption spectra obtained upon laser flash photolysis of 3nCP revealed formation of the triplet excimer states. Triplet sensitization of 33CP using xanthone as the sensitizer demonstrated formation of triplet 33CP via triplet energy transfer whereas from the xanthone ketyl radical formation, it was inferred that triplet xanthone undergoes H atom abstraction from 32CP, providing a benzylic 32CP radical as the counter species. Based on kinetic and spectroscopic data obtained upon laser flash photolysis, differences in photochemical reactions of triplet xanthone between 32CP and 33CP were discussed.

DOI： 10.1021/jp511105v

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Field-effect transistors (FETs) with single crystals of a new phenacene-type molecule, [8]phenacene, were fabricated and characterized. This new molecule consists of a phenacene core of eight benzene rings, with an extended p-conjugated system, which was recently synthesized for use in an FET by our group. The FET characteristics of an [8]phenacene single-crystal FET with SiO2 gate dielectrics show typical p-channel properties with an average field-effect mobility, &lt;mu &gt;, as high as 3(2) cm(2) V-1 s(-1) in two-terminal measurement mode, which is a relatively high value for a p-channel single-crystal FET. The hmi was determined to be 6(2) cm(2) V-1 s(-1) in four-terminal measurement mode. Low-voltage operation was achieved with PbZr0.52Ti0.48O3 (PZT) as the gate dielectric, and an electric-double-layer (EDL) capacitor. The &lt;mu &gt; and average values of absolute threshold voltage, &lt;vertical bar V-th vertical bar &gt;, were 1.6(4) cm(2) V-1 s(-1) and 5(1) V, respectively, for PZT, and 4(2) x 10(-1) cm(2) V-1 s(-1) and 2.38(4) V, respectively, for the EDL capacitor; these values were evaluated in two-terminal measurement mode. The inverter circuit was fabricated using [8]phenacene and N, N'-1H, 1H-perfluorobutyldicyanoperylene-carboxydi-imide single-crystal FETs. This is the first logic gate circuit using phenacene molecules. Furthermore, the relationship between mu and the number of benzene rings was clarified based on this study and the previous studies on phenacene single-crystal FETs.

DOI： 10.1039/c5tc00960j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Transistor characteristics are studied for field-effect transistors (FETs) with thin films of [6]phenacene, which has six benzene rings and W-shape structure. The molecular alignment preferable for FET transport is found to be formed in [6]phenacene thin films. The transistor shows clear p-channel FET characteristics with field-effect mobility mu as high as 3.7 cm(2) V-1 s(-1). The similar O-2 sensing properties to picene FET are observed in [6]phenacene thin film FET. The bias stress properties are observed in [6]phenacene thin film FET. The pulse-voltage application suppresses the bias-stress effect and it enables a continuous O-2 sensing in [6]phenacene FET. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747201]

DOI： 10.1063/1.4747201

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The reaction of o-methylphenylnitrene in the presence of alcohol and amine was expected to give isomeric pairs of 3- and 7-methyl-3H-azepine derivatives. The formation ratio between these isomers was found to be obviously influenced by reaction temperature, that is, reaction at 150 degrees C gave 7-methyl-3H-azepine derivative, however, it became minor under 70 degrees C in both media. The ratio between 3- and 7-methyl derivatives is explained by a scheme of kinetic- and thermodynamic-controlled product distribution from o-methylphenylnitrene to 3- and 7-methyldehydroazepine intermediates which are trapped by nucleophilic media to give 3- and 7-methyl-3H-azepine derivatives.

DOI： 10.1246/cl.2012.400

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

The Cd(P-3(1))- and Hg(P-3(1))-photosensitized emissions of some secondary and tertiary alkyl- and silylamines have been investigated under conditions of steady illumination at 493 and 298 K, respectively. The emission bands were observed at around 440 nm in the cadmium-photosensitized reactions of these amines. In contrast, no appreciable emission bands were observed in the mercury-photosensitized reactions of these amines. However, upon addition of tert-butyl alcohol to the amine-mercury system, an emission band evolved at around 350 nm in the mercury-photosensitization. The peak-wavelengths for secondary and tertiary alkyl- and silylamines are slightly shorter than the values predicted from the correlations between the peak wavelength and the first ionization energy obtained in the cadmium- and mercury-photosensitized luminescence of ammonia and primary amines. The quenching efficiencies of the cadmium and mercury resonance lines by secondary alkyl- and silylamines are higher than those by tertiary alkyl- and silylamines. These observations suggest that the steric hindrance by the alkyl and silyl groups to the approach of the nitrogen atom in the amines to excited cadmium and mercury atoms seems to be an important factor for the stabilization of the exciplexes and the quenching of the resonance lines. The behavior of silylamines is similar to that of alkylamines in cadmium- and mercury-photosensitized reactions. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotochem.2011.11.010

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A 3-trifluoroacetylaminophthalimide selectively distinguished LiI from other alkaline-metal iodides and lithium halides by a marked fluorescence colour change, from orange-yellow to sky-blue, subsequent to 254 nm photolysis.

DOI： 10.1039/c2cc17502a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The cause of regioselectivity for the formation of 3-alkyl- and/or 7-alkyl-3H-azepine derivatives via the intramolecular insertion reaction of o-alkylphenylnitrene, which is generated by an action of Buy on o-alkylnitrobenzene, in the presence of alcohol found to be elucidated by the steric effects of an alcohol adduct on the dehydroazepine intermediate. Observed selectivity is confirmed both by changing the bulkiness of the o-alkyl group of phenylnitrene and that of alcohol as a nucleophile.

DOI： 10.3987/COM-11-12172

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Phthalide derivatives incorporating mono- and di-picolylamino functionalities at the 6-position have been prepared as novel fluoroionophores and their fluorescence responses to metal cations have been investigated. These phthalides not only exhibited efficient fluorescence in an aqueous medium but also displayed fluorescence on-off response upon addition of transition-metal cations, namely Cu(2+). The 6-aminophthalide fluorophore served as the core of the fluorescent probes although it has rarely been applied to a chemosensor. To the best of our knowledge, these modified phthalides are the first 6-aminophthalide-derived fluorometric probes for metal cations, namely Cu(2+).

DOI： 10.1039/c1an15239d

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New carbon-based superconductors are synthesized by intercalating metal atoms into the solid-phase hydrocarbons picene and coronene. The highest reported superconducting transition temperature, T-c, of a hydrocarbon superconductor is 18 K for K(3)picene. The physics and chemistry of the hydrocarbon superconductors are extensively described for Axpicene (A: alkali and alkali earth-metal atoms) for x = 0-5. The theoretical picture of their electronic structure is also reviewed. Future prospects for hydrocarbon superconductors are discussed from the viewpoint of combining electronics with condensed-matter physics: modification of the physical properties of hydrocarbon solids is explored by building them into a field-effect transistor. The features of other carbon-based superconductors are compared to clarify the nature of hydrocarbon superconductors.

DOI： 10.1039/c1cp20961b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

O-2 gas sensing behaviors are studied in picene thin film field-effect transistors (FETs) with hydrophobic polymer (Cytop(TM) or polystyrene) coated SiO2 gate dielectrics. Picene thin film FETs show a rapid reduction of hysteresis in transfer curves recorded in forward and reverse measurement modes, compared to a picene FET with hexamethydisilazane-coated SiO2. The picene FETs show very sensitive O-2 gas sensing effects down to similar to 10 ppm. A quantitative analysis is presented of the gate voltage (V-G) dependent mobility induced by O-2 exposure, i.e., the suppression of drain current at high V-G. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.orgel.2010.06.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Flexible picene thin film field-effect transistors (FETs) have been fabricated with parylene gate dielectric on polyethylene terephthalate substrates. The picene thin film FETs show p-channel output/transfer characteristics and the field-effect mobility mu reaches similar to 1 cm(2) V(-1) s(-1) in vacuum. The FET shows a clear O(2) gas sensing effect and negligible hysteresis in the transfer curves, indicating a possible application of the transistor as O(2) selective gas sensor. Furthermore, it has been found that the parylene gate dielectric can eliminate a reduction in on-state drain current caused by continuous bias-voltage application which is observed if a SiO(2) gate dielectric is used.

DOI： 10.1063/1.3360223

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DOI： 10.1021/jp1041475

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Low voltage operation of picene thin film field-effect transistor (FET) has been realized with 40 nm thick SiO(2) gate dielectrics coated by two polymers, Cytop (TM) and polystyrene. The picene FETs operated in low absolute gate voltage vertical bar V(G)vertical bar below 15 V for Cytop (TM) coated SiO(2) and 30 V for polystyrene coated SiO(2) gate dielectrics, and they showed a significant O(2) gas sensing effect down to similar to 10 ppm. Photoemission spectrum clarified that O(2) molecules penetrate into the thin films at O(2)/picene mole ratio of 1: 1. X-ray diffraction pattern of picene thin films showed highly oriented growth on the polymer-coated SiO(2).

DOI： 10.1063/1.3257373

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

C-60 and picene thin film field-effect transistors (FETs) in bottom contact structure have been fabricated with poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PED-OT:PSS) electrodes for a realization of mechanical flexible organic FETs. The C-60 thin film FETs showed n-channel enhancement-type characteristics with the field-effect mobility mu value of 0.41 cm(2\) V-1 s(-1), while the picene thin film FET showed p-channel enhancement-type characteristics with the p of 0.61 cm(2) V-1 s(-1). The p values recorded for C-60 and picene thin film FETs are comparable to those for C-60 and picene thin film FETs with Au electrodes. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.orgel.2009.01.006

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Transport characteristics and trap states are investigated in picene thin film field-effect transistor under O(2) atmosphere on the basis of multiple shallow trap and release (MTR) model. The channel transport is dominated by MTR below 300 K. It has been clarified on the basis of MTR model that the O(2)-exposure induces a drastic reduction in shallow trap density to increase both the field-effect mobility mu and on-off ratio. We also found that the O(2)-exposure never caused an increase in hole carrier density. Actually, a very high mu value of 3.2 cm(2) V(-1) s(-1) is realized under 500 Torr of O(2).

DOI： 10.1063/1.3076124

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Authorship：Lead author,　Corresponding author   Language：English  

This account provides an overview of the photochemical properties of cyclophanes possessing nitrogen atoms in the bridge chains, namely 2,11-diaza[32]anthracenoparacyclophane and 2,11-diaza[3 2]paracyclophane systems. Although the photoreactions of aromatic molecules that are bound by a linker or fixed in a cyclophane structure have been widely investigated, much less attention has been paid to the photochemistry of aromatic rings incorporated in a nitrogen-bridged cyclophane. During the course of our work on the photoreactions of cyclophanes possessing nitrogen atoms in their bridge chains, the nitrogen-bridged cyclophanes were found to display photoproperties significantly different from those of the nonbridged aromatic chromophores or the corresponding carbonbridged cyclophane analogues. The 2,11-diaza[32]anthracenoparacyclophane system displayed an efficient photochemical cycloaddition-adiabatic cycloreversion cycle in the excited singlet state, while in the triplet state, the photoisomer underwent a novel rearrangement and adiabatic cycloreversion. Upon photolysis of the 2,11-diaza[32]paracyclophane system, an octahedrane cage was formed. This is the first reported octahedrane formation to occur by the photochemical dimerization of benzene. Thus, the title cyclophane systems display a variety of photoprocesses involving cycloaddition, adiabatic cycloreversion accompanied by photoinduced chemiluminescence, novel rearrangements, and previously unknown benzene dimerization. 1 Introduction 2 Photochemistry of the 2,11-Diaza[32]anthracenoparacyclophane System 2.1 General Comments on the Photochemical Cycloaddition and Cycloreversion of Aromatic Molecules in the Singlet State 2.2 Intramolecular Photochemical Cycloaddition and Cycloreversion of the 2,11-Diaza[32] anthracenoparacyclophane System 2.3 General Introduction to the Photochemistry of Aromatic Molecules in the Triplet State 2.4 Photoproperties of the 2,11-Diaza[32]anthracenoparacyclo-phane System in the Triplet State 3 Photochemistry of the 2,11-Diaza[32]paracyclophane System 3.1 General Remarks on the Photoreactions of Cyclophanes Containing Two Benzene Rings 3.2 Construction of the 2,11-Diaza[32]paracyclophane Skeleton 3.3 Photoreactions of the 2,11-Diaza[32]paracyclophane System 4 Summary.

DOI： 10.1055/S-2008-1078574

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG KG  

The diaza[3(2)]cyclophane skeleton has been constructed by the bis-N-alkylation of 1,4-bis[(4-nitrophenylsulfonylamin o)methyl] benzene with 1,4-bis(halomethyl)benzene in the presence of sodium hydride. The 4-nitrophenylsulfonyl (Ns) amides in the bridge chains of the cyclophane were effectively deprotected by sodium ethanethiolate and the resulting free amine moieties were reprotected as the trifluoroacetamide under mild conditions to afford 3,7-bis(trifluoroacetyl)-3,7-diaza-1,5(1,4)-dibenzenacyclooctaphane in 26% overall yield. This Ns-amide method has also been applied for the preparation of a higher homologue, the trifluoroacetamide derivative of triaza[3(3)]cyclophane, 3,5,7-tris(trifluoroacetyl)-3,7, 10-triaza- 1,5(1,3,5)-dibenzenabicyclo[3.3.3]undecaphane, in 18% overall yield. Thus, the present procedure provides a convenient synthetic route to azacyclophane derivatives possessing trifluoroacetamide groups in the bridge chains.

DOI： 10.1055/s-2007-1000825

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ARKAT USA INC  

The effects of solvents and metal cations on the fluorescence spectra of 3- ( 1) and 4- ( 2) trifluoroacetylamino-1,8-naphthalimides were investigated. In MeCN, these naphthalimides displayed a violet similar to blue fluorescence based on their neutral amide form ( 1, 2). Whereas in DMSO, they gave off a yellow similar to orange emission due to their amide anions (1(-), 2(-)). In MeOH, naphthalimide 2 emitted a dual fluorescence (lambda(FL) 436 and 556 nm) to display a white luminescence. Naphthalimides 1, 2 are essentially insensitive to metal cations in their neutral amide form. In contrast, the fluorescence of the amide anions 1-, 2- was quenched by metal cations. The efficiency of the quenching correlated with the Lewis acidity of the metal cations; a stronger Lewis acid tended to display a more effective fluorescence quenching. Therefore, the fluorescence color and the sensitivity to metal cations of the naphthalimides were effectively switched by the solvent.

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Although heating 2-methoxy-2H-azepine results in a [1,5] sigmatropic hydrogen shift, heating 2-propylthio-2H-azepine results in not only a [1,5] sigmatropic hydrogen shift but also a [1,5] sigmatropic propylthio shift. Kinetic measurements reveal that migratory aptitudes increase in the order of MeO &lt; H, PrS. These [1,5] sigmatropic shifts are discussed on the basis of ab initio DFT calculations.

DOI： 10.1021/ol062131w

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING  

The accurate X-ray single-crystal structures of the isoflavone compounds 4-O-methylalpinumisoflavone, O, O-dimethylalpinumisoflavone and 5-O-methyl-4-O-( 3-methylbut-2-en-1-yl) alpinumisoflavone {alpinumisoflavone = 5-hydroxy7-( 4-hydroxyphenyl)-2,2-dimethyl-2H, 6H-benzo[ 1,2-b: 5,4-b']dipyran-6-one} from data sets measured at cryogenic temperature have been obtained from invariom modelling using theoretically predicted Hansen and Coppens multipole-model form factors, which describe the aspherical electron density distribution. Molecular dipole moments and electrostatic potentials obtained from invariom modelling are discussed and compared with results from ab initio theoretical calculations. All three studied compounds are solvent extracts of root bark or seed powder of Millettia thonningii ( leguminosae), a plant molluscicide and cercaricide used in Franco West Africa as medication against various diseases. The compounds' toxicities to brine shrimp have been determined and their different potencies tentatively related to conformation differences, intramolecular contacts, dipole moments and electrostatic potential features.

DOI： 10.1107/S0108768106019616

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

2-Aryl-2H-, 3-aryl-3H-, and 4-aryl-4H-azepine were formed by the novel, electrophilic, pi(LUMO)-controlled reaction of the 2-methoxyazepinium ion, generated in situ by the reaction of TiCl4 with 2,7-dialkoxy-2H-azepine and an aryl compound, for which the kinetic parameters of the sigmatropic hydrogen rearrangement of the 4H-azepine was measured. The substitution and hydrogen shift of the azepinium ion were analyzed with DFT studies. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).

DOI： 10.1002/ejoc.200600257

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

4'-O-Methylalpinumisoflavone crystals which hitherto had been difficult to crystallize for X-ray diffraction analyses have been obtained from a demethylated product of O,O- dimethylalpinumisoflavone. The structural and conformational features of the crystal measured at 90 K are reported and compared with previously reported work of O,O-dimethylalpinumisoflavone and 5-O-methyl-4'-O-(3-methyl-but-2-en-1-yl) alpinumisoflavone. Each of these compounds is characterized by a six membered ring that is further fused to a benzopyrone isoflavone moiety resulting in a tricyclic ring system. This six membered ring shows a half-chair conformation in all the molecules studied, with the ring in the title compound showing the least Cremer-Pople puckering amplitude Q and shorter inter and intramolecular contacts. (C) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/crat.200510656

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The novel azacrowned phthalimide 1 has been prepared and its fluorescence properties have been investigated by addition of EtOH and Ag+. The phthalimide 1 showed appreciable solvatofluorochromism; its fluorescence maxima (lambda(FL)) appeared in the wavelength region between 458 (in Et2O) and 544 nm (in EtOH). In benzene, the phthalimide 1 gave off blue emission (lambda(FL) 466 nm) while it emitted green fluorescence (lambda(FL) 497 nm) upon addition of 250 mM of EtOH. Both the blue and the green emissions were quenched by Ag+. Potential logic operations of the phthalimide 1 were examined using fluorescence outputs at 450 (Out(1)) and 515 nm (Out(2)) and two input stimuli, EtOH (In,) and Ag+ (In-2). The Out, was on in the absence of these inputs while its intensity was reduced (off) by either or both of the inputs to serve as a NOR operator. The Out(2) was off without the inputs; in contrast, the intensity of Out(2) was enhanced (on) by In-2. The enhanced Out(2) was switched off by In-2. The Obt(2), thus, corresponds to an INHIBIT operation responding to the input signals. The crowned phthalimide 1 mimics a two-input-two-output combinational logic gate with a single fluorophore and a single ion-sensing unit.

DOI： 10.1246/bcsj.78.2180

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Although the reactivity of tropylium ion with aromatic substrates is low, the reaction of azepinium ion with aromatic substrates such as benzene, phenol, furan, and thiophene resulted in the formation of 2-aryl-2H-azepine as a major product. An exceptional result in the formation of ring-contracted product was observed in the reaction with pyrrole.

DOI： 10.1021/ol052049l

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The novel azacrowned isoluminol has been prepared as the first luminol analogue possessing an azacrown ionophore. The crowned isoluminol displayed flash chemiluminescence upon addition of alkali-metal iodides in acetonitrile containing alkaline hydrogen peroxide and the chemiluminescence intensity varied depending on the metal cations studied; K+ &gt;&gt; Na+ &gt; Li+.

DOI： 10.1246/cl.2005.1452

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The reaction of 2-methoxy-3H-azepines, in the presence or absence of a nucleophile, with N-bromosuccinimide (NBS) gave a regioselective 1,4-adduct from which the corresponding 2H-azepine derivatives were formed via base-promoted hydrogen bromide elimination, generally in moderate to quantitative yield. Competitive formation of 4-bromo-2-methoxy-3H-azepine by electrophilic substitutuion or 3H-azepin-2-yl 2H-azepin-2-yl ether by transetherification was minimized at lower reaction temperatures. Quantitative substitution of 2-(2',4',6'-trichlorophenoxy)2H-azepine derivatives, formed in moderate yield from the respective 3H-azepine and NBS in the presence of 2,4,6-trichlorophenol (TCP), by various nucleophiles gave the corresponding 2-substituted 2H-azepine. Among these nucleophiles were alkanethiol and alkylamine that are not tolerated in the reaction of 3H-azepine and NBS.

DOI： 10.1021/jo0500232

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.200352794

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The reaction of 5-tert-butyl-2-methoxy-3H-azepine (2a) with sodium alkoxides gave 2-alkoxy-3H-azepine derivatives 3-6 by nucleophilic transetherification. The treatment of 2a with tert-butyllithium also yielded 2,5-di-tert-butyl-3H-azepine (7): however, the reaction of 2a and methyllithium gave the expected 5-tert-butyl-2-methyl-3H-azepine (8) along with unexpected 5-tert-butyl-2,2-dimethyl-2,3-dihydro-1H-azepine (9). but also 5,5'-di(tert-butyl)-2,2'-methylenedi(3H-azepine) (11), the structure of which was found to be tautomerized 5-tert-butyl-2-(5-tert-butyl-2,3-dihydro-1H-azepine-2-ylidenemethyl)-3H-azepine (12). The energy profile for the observed tautomerization is discussed based on ab initio DFT calculations and kinetic measurements.

DOI： 10.1246/bcsj.76.805

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UVA-irradiation of the photo-Fenton reagents N-isopropoxypyridone 2b and N-isopropoxythiazole-2(3H)-thione 3b releases radicals which induce strand breaks. Transient spectroscopy establishes N-O bond scission [Phi(N-O) = (75 8)% for 2b and (65 7)% 3b] as the dominating primary photochemical process to afford the DNA-damaging radicals. Product studies and laser-flash experiments reveal that the thiazolethione 3b leads primarily to the disulfide 5, from which through C-S bond breakage, the bithiazyl 6, the thiazole 7, and the isothiocyanate 8 are derived. Upon irradiation of pyridone 2b (300 nm) in aqueous media, a mixture of isopropoxyl and 2-hydroxyprop-2-yl radicals is formed, as confirmed by trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and EPR spectroscopy. In contrast, the photolysis of the thiazolethione 3b (350 nm) affords exclusively the DMPO adducts of the isopropoxyl radicals. Control experiments disclose that the thiazolethione-derived photoproduct disulfide 5, or the intermediary thiyl radicals B, scavenge the carbon-centered 2-hydroxyprop-2-yl radicals, which are generated from the isopropoxyl radicals by hydrogen shift. With supercoiled pBR 322 DNA in a 60:40 mixture of H2O-MeCN, the pyridone 2b and the thiazolethione 3b display moderate strand-break activity (17% open-circular DNA for 2b and 12% for 3b). In pure water, however, the pyridone 2b photoinduces substantially more DNA cleavage (32% open-circular DNA), which is attributed to the peroxyl radicals generated from the 2-hydroxyprop-2-yl radicals by oxygen trapping. The lower strand-break activity of the thiazolethione 3b derives presumably from isopropoxyl radicals, because only these are detected in the photolysis of this photo-Fenton reagent.

DOI： 10.1021/jo025856w

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Reaction of 5-t-butyl-2-methoxy-3H-azepine (2) with nuclephiles (alkoxides or t-butyllithium) gave respective substitution product at 2-position of the ring. Unexpectedly, when methyllithium was used as a nucleophile, bis(5-t-butyl-3H-azepin-2-yl)methane (7), the structure of which found to be tautomeric vinamidine (7a,b), was formed. Tautomerization between 7 and 7a,b was characterized spectroscopically and theoretically based on the levels of B3LYP/631G(d).

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Authorship：Lead author  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A guest-sensitive chemiluminophore, a novel crown-ether-modified lophine peroxide 1. has been prepared. and its chemiluminescent behavior has been investigated in the presence of alkaline and alkaline earth metal cations. In the presence of Na+, the lambda (max) of the chemiluminescence of peroxide 1 was blue-shifted (505 nm) compared to the case without a metal cation (566 nm). The chemiluminescent intensity was enhanced by addition of Na+ while that of Mg2+ decreased the intensity. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(01)01572-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC PHOTOBIOLOGY  

On irradiation of N-hydroxythiazole-2(3H)-thione 3 at 300 nm, the photoproducts disulfide 4, bisthiazole 5 and thiazole 6 are formed. During this photolysis, hydroxyl radicals are released, which have been detected by spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), coupled with electron paramagnetic resonance spectroscopy. In the presence of supercoiled pBR322 DNA, irradiation of thiazolethione 3 induces strand breaks through the photogenerated hydroxyl-radicals, as confirmed by control experiment with the hydroxyl-radical scavenger isopropanol, Singlet oxygen appears not to be Involved, as attested by the lack of a D2O isotope effect. During the photoreaction of thiazolethione 3 in the presence of 2'-deoxyguanosine (dG), the latter is photooxidized (ca 10% conversion after 2 h of irradiation) to the 7,8-dihydro-8-oxo-2'-deoxyguanosine as the main oxidation product. The dG conversion levels off after complete consumption of thiazolethione 3 and is suppressed by the addition of the hydroxyl-radical scavenger 2,6-di-tert-butyleresol or DMPO, Since the photoproducts 4-6 are ineffective as sensitizers for the photooxidation of dG and DNA, the hydroxyl radicals released in the photolysis of thiazolethione 3 are the oxidizing species of DNA and dG, These results suggest that the thiazolethione 3 may serve as a novel and effective photochemical hydroxyl-radical source for photobiological studies.

DOI： 10.1562/0031-8655(2000)072<0619:NHCTHT>2.0.CO;2

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

The conformation of 2,11-diaza[3.3](9,10)anthracenoparacyclophane 1, which underwent photointerconversion with isomer 2, was fixed with the aid of a chiral camphanic auxiliary to have molecular chirality, and the photochemiluminescence from the modified 2a was circularly polarized reflecting the chirality of the emitting state.

DOI： 10.1039/a801296b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

The selective formation of 2-methoxy-2H-azepine from 3H-azepines, via a likely azatropylium cation, is reported
the first isolation of 2-azanorcaradiene, which is considered to be the valence isomer of 3H-azepine, is also described.

DOI： 10.1039/a703709k

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemical Society of Japan  

The efficiency for excited product formation in the adiabatic photocycloreversion of bridged biplanemer 1 was controlled by the size of its side-chain substituents which changed the interchromophore distance in the photoproduct 2.

DOI： 10.1246/cl.1997.873

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemical Society of Japan  

A reaction of electrophilic bromination of norbornadiene homologs such as bicyclo[2.2.2]octa-2,5-diene (4) and bicyclo[3.2.2]nona-6,8-diene (7) with bromine gave hitherto unknown skeleton rearranged dibromides. The rearrangement may proceed via a bromonium cation of starting diene to give bicyclo[3.2.1]octene or bicyclo[3.3.1]nonene skeleton in respective cases. The observed rearrangement reactions are also confirmed in 6,7-bis(methoxycarbonyl) derivatives of bicyclodiene 7 under similar conditions.

DOI： 10.1246/bcsj.69.453

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemical Society of Japan  

A new ring contraction reaction giving pyridine derivatives from 3,6-and 2,5-di-tert-butyl-3H-azepines was observed by a successive treatment with bromine and aqueous K2CD3. A plausible mechanism via azatropilium cation for the rearrangement was discussed based on the product's distribution from respective 3H-azepines.

DOI： 10.1246/cl.1996.1129

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Language：English   Publisher：The Chemical Society of Japan  

The electronic absorption spectrum of a 1,4-difluorobenzene–naphthalene biplanemer 1 exhibited a characteristic absorption band around 290 nm. This was attributable to intramolecular charge transfer interaction between the longicyclic conjugated π system and the benzene chromophore. The oxidation potential of 1 was 1.70 V (vs. Ag/AgCl), which was lower than those of the related compounds in which one of the double bonds of 1 was hydrogenated. Thermally, the biplanemer 1 underwent facile Cope rearrangement, followed by dehydrofluorination, to give 1-(4-fluorophenyl)naphthalene and 2-(3-fluorophenyl)naphthalene.

DOI： 10.1246/bcsj.68.3557

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Language：English   Publishing type：Research paper (scientific journal)  

Demethoxycarbonylation of methyl 2,5-di-tert-butyl-1H-azepine-1-carboxylate using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) gave 3H-azepines. Under similar conditions, methyl 3,6-ditert-butyl-1H-azepine-1-carboxylate gave not only the 3H-azepine but also the isomerized 2H- and 4H-azepines. Application of the reaction to dimethyl and diisopropyl substituted 1H-azepines showed that bulky alkyl group substitution stabilizes the seven-membered azatriene system. The thermal behaviour of the di-tert-butyl substituted azepines is discussed.

DOI： 10.1039/p19940001753

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Authorship：Lead author   Language：English   Publisher：The Chemical Society of Japan  

A naphtalene-1,4-difluorobenzene biplanemer 1a has been prepared through the electrolytic oxidative didecarboxylation. The direct irradiation of 1a gave 1,4-difluorobenzene and excited naphthalene in both a singlet state (Φ_f = 0.098) and a triplet state (Φ_p = 0.029) at 77 K in EPA. In the triplet-sensitized reaction, the biplanemer 1a underwent intramolecular [2π+2π] cycloaddition to give a cage compound instead of the formation of the triplet naphthalene.

DOI： 10.1246/bcsj.66.2436

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9,10-difluorotetracyclo[6.4.21,8.29,12.02,7]hexadeca-2,4,6,10,13,15-hexaene-3, 6-dione is thermally labile and shows a notably clear, long wave-length CT absorption. © 1992.

DOI： 10.1016/S0040-4039(00)60910-3

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Language：English   Publisher：The Chemical Society of Japan  

[Ru(&eta;⁵-C₅H₅)(&eta;⁶-arene A)]BF₄ (arene A = nitrobenzene, m- or p-nitrotoluene, anisole, phenetole, m- or p-methylanisole) were quantitatively converted to pure [Ru(&eta;⁵-C₅H₅)(&eta;⁶-arene B)]BF₄ (arene B = phenoxido-2d m- or p-monodeuterated methylphenoxido) in the presence of excess KOH in CD₃OD, whereas [Ru(&eta;⁵-C₅H₅)(&eta;⁶-anisole)] BF₄ was quantitatively obtained by treatment [Ru(&eta;⁵-C₅H₅)(&eta;⁶-nitrobenzene)] BF₄ with 1 equivalent KOH or CH₃OK.

DOI： 10.1246/bcsj.65.2557

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Language：English   Publishing type：Research paper (scientific journal)  

Demethoxycarbonylation of methyl 2,5,-di-tert-butyl-1H-azepine-1- carboxylate using 1,8-diazabicyclo[5.4.0]undec-7-ene gives exclusively two isomers of 3H-azepine derivatives, while methyl 3,6-di-tert-butyl-1H-azepine-1- carboxylate gives a mixture of 2H-, 3H- and 4H-azepine derivatives under the same conditions because of a 1,5-hydrogen shift in the resulting triene system.

DOI： 10.1039/C39910001154

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Electronic oxidative bisdecarboxylation of photoadducts of 2,5-dihalo-1,2-dihydrophthalic anhydride and anthracene gave the corresponding energy-rich heterodimers 12 and 13. The quantum yields of the formation of the excited anthracene from 12 and 13 by the irradiation of 280-nm light were 0.65 and 0.25, respectively. We assumed that the heterodimers of 12 and 13 form biradicaloid intermediates during thermal retro [4πs + 4πs] cycloaddition and consumed their stored energy without any visible light. However, we observed emission light from 340 to 460 nm through a glass filter and the formation of anthracene using Nd-YAG laser IR light (1.06 μm) by the multiphoton absorption, when fine powders of 12 and 13 were used. © 1988, American Chemical Society. All rights reserved.

DOI： 10.1021/jo00252a004

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Language：English   Publishing type：Research paper (scientific journal)  

9,12-Difluoro-and 9,12-dichlorotetracyclo[6.4.2.2&lt
sup&gt
9.12&lt
/sup&gt
.0&lt
sup&gt
2.7&lt
/sup&gt
] hexadeca-2,4,6,13,15-pentaene-10,11 -dicarboxylic anhydrides (2a) and (2b) were prepared by 4π&lt
inf&gt
s&lt
/inf&gt
+ 4π&lt
inf&gt
s&lt
/inf&gt
is photocycloaddition between cis-3,6-difluoro-or cis-3,6-dichloro-1,2-dihydrophthalic anhydride and naphthalene, respectively. 12, 15-Difluoro-and 12, 15-dichlorohexacyclo [8.6.0.0&lt
sup&gt
2.15&lt
/sup&gt
.0&lt
sup&gt
3.8&lt
/sup&gt
.0&lt
sup&gt
9.12&lt
/sup&gt
.0&lt
sup&gt
11.16&lt
/sup&gt
] hexadeca-3,5,7-triene-13,14-dicar-boxylic anhydrides (6a) and (6b) were obtained by 2π&lt
inf&gt
s&lt
/inf&gt
+ 2π&lt
inf&gt
s&lt
/inf&gt
is intramolecular photocycloaddition of adducts (2a) and (2b), respectively. 12,15-Difluorohexacyclo[8.6.0.0&lt
sup&gt
2.15&lt
/sup&gt
.0&lt
sup&gt
3.8&lt
/sup&gt
.0&lt
sup&gt
9.12&lt
/sup&gt
.0&lt
sup&gt
11.16&lt
/sup&gt
]hexadeca-3,5,7,13-tetraene (7a) has been synthesized by the electro-oxidative decarboxylation of anhydride (6a) and the excited singlet naphthalene has been observed on irradiation of adduct (7a), and is presumably formed via an adiabatic pathway. © 1988, The Royal Society of Chemistry.

DOI： 10.1039/P19880003307

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Total pages：xii, 422p, 図版 [8] p   Language：Japanese

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Total pages：xvi, 418p   Language：Japanese

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

DOI： 10.1142/9789812702203_0043

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