川瀬 毅

N-di(isopropyl)phenyl-2-azaphenalenyl radical cations were obtained as a dark brown air-sensitive crystalline compound. The high HOMA values and the ACID calculation indicate relatively high aromatic character of a 5,8-di-tert-butyl derivative, and...

Abstract Despite having an asymmetric structure, 2‐(thiopyran‐4‐ylidene)‐1,3‐benzodithiole (TP‐BT) is a good p‐type semiconductor containing isotropic three‐dimensional (3D) intermolecular interactions. Moreover, its π‐extended analogs can potentially work as organic electronic materials. Herein, a fused‐type π‐extended analog containing an extra benzene ring on the benzodithiole unit, i. e., 2‐(thiopyran‐4‐ylidene)‐1,3‐naphtho[2,3‐d]dithiole (TP‐NT), and three σ‐bonded‐type π‐extended analogs, i. e., phenyl‐, naphthyl‐, and anthryl‐substituted analogs (Ph‐TP‐BT, Nap‐TP‐BT, and Ant‐TP‐BT, respectively), were prepared and their molecular arrangements and organic field‐effect transistor (OFET) properties were investigated. TP‐NT formed a herringbone arrangement with 3D intermolecular interactions similar to that of the parent TP‐BT. Meanwhile, Ant‐TP‐BT formed a bilayer‐type layered herringbone arrangement. Since the highest occupied molecular orbital and the lowest unoccupied molecular orbital are located on the TP‐BT and anthracene units, respectively, a unique donor–acceptor separated network was formed. In OFETs prepared via a vapor deposition method using the σ‐bonded‐type analogs, slightly lower mobilities (0.1 to 8×10⁻³ cm²/Vs) than that of TP‐NT (0.1 cm²/Vs) were observed. Upon photo‐irradiation, the OFET of Ant‐TP‐BT exhibited a larger threshold voltage shift and an increase in the off current compared with TP‐NT. The σ‐bonded‐type analogs showed a larger photo‐response effect than TP‐NT derived from the donor–acceptor molecular structure.

We report the synthesis of aryl-substituted TP-BT derivatives and their OFET properties. 4-Pyridyl substituted TP-BT shows switching characteristics by photo-irradiation.

We report the synthesis of P-BT and TP-BT and their OTFT properties based on electronic dimensionality and access resistance (R_acc). TP-BT can suppress R_acc due to its 3D electronic structure.

A novel alkyltolane-terminated cyanostilbene is synthesized. The photoluminescence colour changed depending on the precipitation method, with either a red shift or blue shift in the photoluminescence spectra observed upon mechanical grinding.

© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim A soluble directly 2,2′-linked tetracene dimer was synthesized. Dimerization of 8-bromo-2,3-dihexyl-5,12-tetracenequinone afforded the corresponding bitetracenequinone, which was converted into a tetracene dimer by sequential addition of 1-hexynyllithium and SnCl 2 /HCl. The synthesized tetracene dimer with four hexyl and four 1-hexynyl groups was highly soluble in CH 2 Cl 2 and THF, and the solutions were unstable under air and room light. The compound was studied by X-ray single crystal analysis, UV/Vis, and fluorescence spectroscopy, cyclic voltammetry, and density functional theory (DFT) calculations. In the crystal, two tetracene rings take a coplanar conformation although DFT calculations demonstrated that such a molecular structure is energetically unfavorable. The tetracene dimer had red-shifted absorption maxima and large molar extinction coefficients compared with the corresponding tetracene monomer. The tetracene dimer also showed amphoteric redox properties and p-type semiconducting behavior.

The Diels-Alder (DA) reaction of diacenaphtheno[1,2-b;1',2'-d]thiophene (1a) with benzyne affords 1:1 and 1:2 adducts, 7 and 8, in 47 and 11% yields. An X-ray crystallographic analysis reveals that 8 possesses a dibenzobarrelene structure involving a rigid di(1-naphthyl)ethene moiety. Thus, the second DA reaction occurs at the central benzene ring of 7 selectively. The 1:2 adduct 8 emits intense blue fluorescence in CH2Cl2. Moreover, we examined the DA reactions of la and tetra-t-butyl derivative lb with p-benzoquinone to afford acenaphtheno[1,2-j]fluoranthene 10a, and its tetra-t-butyl derivative 10b and a quinone 11b, respectively. Novel fragmentation reaction should occur to produce the acenaphtheno-fluoranthene frameworks of 10. An X-ray crystallographic analysis reveals a rather planar structure of 11b. The central benzene ring of lib shows large bond alternation by the Mills-Nixon effect. The compounds 10a and 10b emit sky blue fluorescence with moderate Phi(SN) values. The electronic properties of new compounds are well consistent with the theoretical predictions. (C) 2017 Elsevier Ltd. All rights reserved.

Herein a mechanoresponsive luminophore containing a pyridine ring at the molecular terminal is synthesized. The chromophore powder exhibits blue photoemission in the initial state, but turns green upon mechanical grinding. The chromophore forms a complex when combined with materials containing an acid group and a halogen. Furthermore, the mechanoinduced photoluminescence color of the halogen complex changes from bluish green to yellowish green, while that of the acid complex turns from orange to red. These results demonstrate that the mechanoresponsive color shift can be tuned.

The title carbene (4) was generated as a highly reactive species in solution by photoirradiation of 10-diazobicyclo[6.3.0] undecapentaene (5) using a high-pressure mercury lamp. Carbene 4 reacts with benzene to afford two isomeric adducts, 10-phenylbicyclo[6.3.0] undecapentaene (10) and tricyclo[9.3.0(3,10).0]heptadeca-1,3(10),4,6,8,12,14,16-octaene (11). The reactivity toward benzene is a characteristic of an electrophilic aromatic carbene analogous to cyclopentadienylidene 1. In contrast, the reaction of 4 with methanol produces 7-methoxybicyclo[6.3.0] undeca-1,3,5,8,10-pentaene (15). When [D-1] methanol was employed as a reactant, the 10-deuterated analogue was formed. The results clearly indicate the formation of bicyclo[6.3.0] undecapentaenyl cation (7) as a novel 10 pi-electronic compound by protonation of 4. Theoretical calculations indicate that the 2- and 7-positions of the cation have the largest positive charge in the cation. Moreover, the carbene was generated in the presence of tert-butyl hydroperoxide in aqueous tetrahydrofuran to afford azulene through oxidation of 7, followed by decarbonylation. The nucleophilic property of carbene 3 is similar to that of cycloheptatrienylidene 2. Thus, 4 can be regarded as a novel ambiphilic aromatic carbene.

A new tetrabenzofluorene fluorophore, containing 2,2-dicyanoethenylphenyl groups, was synthesized and subjected to photophysical studies. This substance was found to exhibit a relatively intense fluorescence in various organic solvents associated with remarkable solvatofluorochromism [Delta lambda(EM) = 170 nm (5060 cm(-1)d) from cyclohexane to CH2Cl2]. In addition, the tetrabenzofluorene derivative displays crystallization-induced enhanced emission (CIEE) in aqueous THF solutions. The results of theoretical calculations show that this substance has a low energy LUMO and that a high level of spatial separation exists between its HOMO and LUMO. This finding suggests that the ground-to-excited state electronic transition of this substance should have intramolecular charge-transfer character. In addition, the tetrabenzofluorene derivative serves as a turn-on fluorescent sensor for cyanide by displaying an intense bluegreen fluorescence in the presence of cyanide ions.

Diels–Alder reactions of acenaphthylene-5,6-dicarboximide (AI) derivatives with the corresponding dienes afforded some derivatives of π-extended fluoranthene imide, namely N-(2-ethylhexyl)-7,10-diphenylfluoranthene imide (DPFI) and N-(2-ethylhexyl)-7,8,9,10-tetraphenylfluoranthene imide (TPFI), N-(n-octyl)-benzo[k]fluoranthene imide (BFI), and N-(n-octyl)-naphtho[k]fluoranthene imide (NFI). Molecular structures of TPFI and BFI reveal that the core π-skeletons have a highly planar structure, and the molecules form a dimeric structure in the crystals. The absorption spectra exhibit bathochromic shift with π-extension of the core π-skeletons. On the other hand, DPFI and TPFI show the long-wavelength emission related to BFI, probably due to π-extension toward the phenyl substituents in the excited states. BFI and NFI exhibited an interesting concentration-dependent ¹H-NMR behavior in CDCl₃, suggesting self-aggregation formation. Moreover, BFI and NFI show moderate and remarkable solvatofluorochromism in solutions (BFI for Δλ_EM = 67 nm, NFI for Δλ_EM = 116 nm), respectively, while DPFI and TPFI show weak solvatofluorochromism. The density functional theory calculations demonstrate that the considerable spatial separation between the HOMO and LUMO coefficients in the NFI molecule. The result indicates that the ground-to-excited state transition of NFI should have intramolecular charge transfer (ICT) character.

The substituent effect on optical properties of 3,14-diphenyl-17,17-di(n-pentyl)tetrabenzofluorene derivatives bearing electron-withdrawing groups(NC, CH3OCO, CH3SO2, and OHC) at 4-position of the phenyl groups were investigated. These compounds were readily prepared by using Suzuki-Miyaura cross-coupling as a key step. The 4-cyano, 4-methoxycarbonyl, and 4-methylsulfonyl derivatives display intense blue to blue-green fluorescence in CH2Cl2 and in the solid states. On the other hand, the title compound forms two polymorphs, and thus, exhibit crystallochromism in fluorescence; the prismatic crystal emits intense yellow fluorescence, and the other crystal form does blue-green fluorescence. Moreover, the compound shows large solvatofluorochromism(Delta lambda(EM) = 67 nm). The crystallographic analysis of the prismatic crystal reveals that the tetrabenzofluorene moiety of the compound possesses a helical structure with a C2 symmetry and the molecules form a herringbone-like structure. The density function theory calculations predict the remarkable intramolecular charge-transfer character of the compound. The prediction is in good agreement with the observed fluorescence properties. (C) 2017 Elsevier Ltd. All rights reserved.

17H-Tetrabenzo[a,c,g,i]fluoren-17-one possessing a nonplanar, helicene-like structure was efficiently prepared by aerial oxidation of 17H-tetrabenzo[a,c,g,i]fluorene under mild basic conditions. A quinone methide and an unsymmetrical fulvalene containing a tetrabenzofluorene unit were synthesized from the ketone. Treatment of 17-bromotetrabenzo[a,c,g,i]fluorene with a base afforded a symmetric fulvalene as an air-sensitive blue solid. Electrochemical analyses revealed that these compounds have high electron affinities.

A series of 2,3-diphenylphenanthro[9,10-b]furans were prepared by the reactions of phenanthrene-9,10-dione with two equivalents of benzylidenetriphenylphosphoranes as a key step. The bis(4-bromophenyl) derivative can be readily lithiated by the action of n-butyllithium in diethyl ether. The corresponding 4-trimethylsilyl and 4-methylthio derivatives were obtained by quenching the dilithio derivative with trimethylsilyl chloride and dimethyl disulfide, respectively. The Buchwald-Hartwig amination of the bromide with diphenylamine afforded the diphenylamino derivative in a good yield. Crystallographic analysis of the parent diphenyl derivative reveals that the phenanthrofuran moiety has a slightly twisted helicene-like structure, and the compound forms a columnar stacking in the crystal. The phenanthrofurans display intense blue fluorescence both in CH2Cl2 and in the solid state. Their electrochemical properties obviously indicate high HOMO energy levels of the furans, as predicted by density functional theory calculations.

Cyclic conjugated systems involving an exo-methylene unit in the ring system are generally termed fulvenes. In order to elucidate their aromatic character, fulvenes have received much attention from a large number of chemists for a long time. Pentafulvenes, a structural isomer of benzene, triafulvenes, and heptafulvenes are representative examples of the class of compounds. Fulvene derivatives can serve as building blocks for the construction of the polycyclic conjugated systems. Triapentafulvalene, pentafulvalenes, sesquifulvalene, and heptafulvalene are representative examples of fulvalenes. This chapter explores heterofulvenes and heterofulvalenes from the viewpoint of their electronic properties that is, how the replacement of the skeletal carbon atoms of fulvenes and fulvalenes byheteroatoms affects their properties. Among these derivatives the fully conjugated cyclic ketones cyclopropenone (CPN), cyclopentadienone (CPDN), and tropone are categorized as oxafulvenes. The reactions between benzotriafulvenes and transition metals afford metallacyclobutane derivatives as stable crystalline compounds in good yields.

Trifluoromethylphenyl-substituted phthalimide derivatives favorably form triboluminescence (TL) active noncentrosymmetric crystals. Oligothienyl-, oligophenyl-, and naphthyl-substituted phthalimide derivatives were successfully developed as a series of metal free TL compounds. X-ray crystal structure analyses of bithienyl and naphthyl derivatives revealed noncentrosymmetric layer structures in the same direction. Introduction of suitable electron rich pi-units such as thienyl groups enhances their photoluminescence and TL characteristics, and the colors can be also controlled in the visible region. A rigid naphthyl-substituted imide derivative exhibits extremely high TL performance.

The asymmetric unit of the title compound, C18H16O4, contains two crystallographically independent molecules. The anthraquinone ring systems are slightly bent with dihedral angles of 2.33 (8) and 13.31 (9)° between the two terminal benzene rings. In the crystal, the two independent molecules adopt slipped-parallel π-overlap with an average interplanar distance of 3.45 Å, forming a dimer the centroid-centroid distances of the π-π interactions are 3.6659 (15)-3.8987 (15) Å. The molecules are also linked by C-H⋯O interactions, forming a tape structure along the a-axis direction. The crystal packing is characterized by a dimerherringbone pattern.

Recrystallization of 1,4-dipropoxy-9,10-anthraquinone from hexane solution afforded two polymorphs: red prisms and yellow needles. X-ray crystallographic analyses revealed that the molecular arrangement was an anti-parallel orientation for red solids and a slipped-parallel orientation for yellow solids. The difference in solid-state color was analyzed by TD-DFT calculations of their multimers.

The title imides possessing a planar acenaphthofluoranthene moiety were prepared by the Diels-Alder reaction of diacenaphtho[1,2-b:1',2'-d]thiophene and maleic anhydride and subsequent treatment with amines. The reaction with maleimide afforded the corresponding 1:2 adduct displaying intense blue fluorescence in solution. Although the imides crystallize yellow needles, their amorphous solids are red. Concentration-dependent (HNMR)-H-1 spectra of a N-octyl derivative reveal self-aggregation behavior in CDCl3.

New pyreno[4,5-b]furan and pyreno[4,5-b:9,10-b']difuran derivatives displaying intense blue fluorescence in CH2Cl2 were efficiently synthesized through the reactions of pyrene-4,5-dione and 2,7-di-tert-butylpyrene-4,5,9,10-tetraone with benzylphosphoranes as a key step. X-ray crystallographic analysis reveals that both pyrenofurans have a planar structure, and their electrochemical properties obviously indicate high HOMO energy levels as predicted by density functional theory (DFT) calculations.

The title anion 1 was generated as a fairly thermally stable species in tetrahydrofuran (THF) and dimethylsulfoxide (DMSO) by the action of several bases (sodium hydride, potassium hydride, lithium diisopropylamide, and lithium hexamethyldisilazide) with appropriate bicyclo[6.3.0]undecapentaenes. Variable-temperature (HNMR)-H-1 spectra of 1Li(+) in [D-8]THF reveal that the anion exhibits exceptionally large ion-pairing effects; proton chemical shifts vary by more than 1ppm as a function of ion-pairing conditions. Thus, anion 1, in a contact ion pair (Li+ at ambient temperature in THF), behaves as an aromatic cyclopentadienyl anion that is perturbed only slightly by the electronic effects of a paramagnetic cyclooctatetraene (COT), whereas 1 in a separated ion pair (Li+ at low temperatures in THF or at ambient temperature in DMSO) behaves as an overall paratropic species with a 12 -electron periphery. (CNMR)-C-13 spectroscopy indicates no major skeletal rearrangement and only small variations of the electron density. The variable tropicity of 1 can be ascribed to small conformational changes of the molecule. In addition to its unusual, tunable tropicity, anion 1 can also serve as a versatile building block for the synthesis of cyclopentanoid conjugated systems fused to a fully unsaturated eight-membered ring. A theoretical calculation predicts that the 10-position of 1 should have the highest electron density. In agreement with this prediction, the reactions of 1 with electrophiles occur predominantly at the 10-position. The corresponding ferrocene, two fulvenes, two diazo derivatives, and a COT-fused azulene were obtained by the reactions of 1 with appropriate electrophiles.

A series of 2,3-dialkyltetracenes (alkyl = propyl to hexyl) were readily prepared from 2,3-dialkyl-5,12-tetracenequinone by a one-pot sequence involving hydride reduction with sodium borohydride and subsequent addition of tin(II) chloride in concd hydrochloric acid. X-ray diffraction patterns of their recrystallized powder samples demonstrated their crystalline nature. X-ray crystallographic analysis of the butyl derivative revealed that there were two disordered sets of butyl groups with 50% occupancies, and that in the molecular structure, one butyl group was coplanar with the tetracene core, while the other butyl group was perpendicular to the tetracene plane. Further, the crystal structure adopted a repeating bilayer structure of herringbone-packed tetracene cores and disordered alkyl groups. The conformational analysis demonstrated that there were a number of stable conformers, which would account for the occurrence of alkyl disorders. Flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurements of 2,3-dialkyltetracenes exhibited an increase in the product of charge carrier mobility (3.0 × 10-5to 3.5 × 10-4cm2V-1s-1) and its generation efficiency with increase in the length of the alkyl side chains, suggesting that a longer alkyl side chain plays an important role in the degree of transfer integral and in the suppression of charge recombination or exciton quenching.

A major deficit in suitable dyes is stifling progress in the dye-sensitised solar cell (DSC) industry. Materials discovery strategies have afforded numerous new dyes; yet, corresponding solution-based DSC device performance has little improved upon 11% efficiency, achieved using the N719 dye over two decades ago. Research on these dyes has nevertheless revealed relationships between the molecular structure of dyes and their associated DSC efficiency. Here, such structure-property relationships have been codified in the form of molecular dye design rules, which have been judiciously sequenced in an algorithm to enable large-scale data mining of dye structures with optimal DSC performance. This affords, for the first time, a DSC-specific dye-discovery strategy that predicts new classes of dyes from surveying a representative set of chemical space. A lead material from these predictions is experimentally validated, showing DSC efficiency that is comparable to many well-known organic dyes. This demonstrates the power of this approach.

The asymmetric unit of the title compound, C14H 6O4, contains three independent molecules (A, B and C). In molecule C, there are two disordered sets of two carbonyl O atoms [occupancies = 0.643(11) and 0.357(11)]. All three molecules are non-planar due to repulsion between two O atoms in peri positions on the anthracene ring, showing a slight difference in deviation of the carbonyl O atoms. The intramolecular distances between the two nearest O atoms are in the range of 2.685(10)-2.766(10)Å. In the crystal, molecules are linked by C - H⋯O and π-π [centroid-centroid distances = 3.615(2), 3.844(2) and 3.921(2)Å] interactions, which lead to the formation of a herringbone-like arrangement.

A series of 17,17-dialkyl-3,14-diaryltetrabenzofluorenes were efficiently prepared by using SuzukiMiyaura cross-coupling reactions of the corresponding 3,14-dibromo derivatives. Studies of the unique fluorescence properties of these compounds showed that they display intense blue to yellow fluorescence with high quantum yields in the solution state and blue to orange fluorescence with moderate quantum yields in the solid state. In addition, the fluorescence wavelength of the bis(p-nitrophenyl) derivative is remarkably solvent-dependent in a manner that correlates with the solvent polarity parameter ET(30). The results of density function theory calculations suggest that the intramolecular charge-transfer character of the HOMOLUMO transition is responsible for the large solvent effect. Moreover, addition of water to a tetrahydrofuran (THF) solution of this compound leads to quenching of the yellow fluorescence owing to an increase in the solvent polarity. However, when the amount of water fraction exceeds 70?%, a new fluorescence band appears at the same orange-red emission wavelength as that of the solid-state fluorescence. This observation suggests the occurrence of a crystallization-induced emission (CIE) phenomenon in highly aqueous THF.

A series of bromotetracenequinones 1 and bromotetracenes 2 were prepared from 4-bromophthalic anhydride. The parent tetracenequinone 1a and tetracene 2a were sparingly soluble in organic solvents. In contrast, dipropyl-substituted tetracenequinone 1b and tetracene 2b were a little more soluble. Preparation of dihexyl-substituted tetracene 2c proved to be difficult. Sonogashira coupling of 1b with trimethylsilylacetylene afforded the corresponding product. © 2012 Springer Science+Business Media B.V.

The whole molecule of the title compound, C14H8I2, is generated by crystallographic twofold symmetry. The molecule is planar [maximum deviation = 0.0323 (6) Å] with the I atoms displaced from the mean plane of the phenanthrene ring system by only 0.0254 (5) Å. In the crystal, molecules form face-to-face slipped antiparallel π-π stacking interactions along the c axis with an interplanar distance of 3.499 (7) Å.

The phenanthrene ring in the title compound, C14FH 8Br2, is approximately planar [maximum deviation = 0.039(3)Å]. In contrast, the two bromo atoms are displaced slightly from the phenanthrene plane [maximum deviation = 0.1637(3)Å]. In the crystal, the molecules adopt a herringbone-like arrangement and form face-to-face slipped π-π stacking interactions along the b axis, with an interplanar distance of 3.544(3)Å and slippage of 1.81Å. The crystal studied was a racemic twin with a minor twin fraction of 0.390(10).

The title compound, C16H12O4, crystallizes with two half-molecules in the asymmetric unit, each of which is completed by a crystallographic inversion center. The two crystal-lographically independent molecules have almost the same geometry and are almost planar [maximum deviations = 0.018 (3) and 0.049 (3)Å]. They adopt a conformation in which the Cmethyl - O bonds are directed along the molecular short axis [C - C - O - C torsion angles of 179.6 (2) and 178.0 (2)°]. In the crystal, the molecular packing is characterized by a combination of a columnar stacking and a herringbone-like arrangement. The molecules form slipped π-stacks along the b axis, in which there are two kinds of columns differing from each other in their slippage. The interplanar distances between neighboring molecules are 3.493 (3) for one column and 3.451 (2)Å for the other.

Mol-ecules of the title compound, C18H16O6, are almost planar [maximum deviation = 0.096 (4) Å] and reside on crystallographic centres of inversion. They adopt a conformation in which the Cmeth-yl-O bonds are directed along the mol-ecular short axis [C-C-O-C torsion angles of-175.3 (3) and 178.2 (3)°]. In the crystal, mol-ecules adopt a slipped-parallel arrangement with π-π stacking inter-actions along the a axis with an inter-planar distance of 3.392 (4) Å. Weak C-H⋯O inter-actions link the mol-ecules into sheets parallel to (10-2).

2,3,6,7-Tetrapropoxy- and 2,6-dipropoxy-substituted 9,10-anthraquinone (AQ) and anthracene (ANT) derivatives were synthesized, and their optical properties in solution and in the solid state were investigated. In AQs, the tetrapropoxy derivative exhibited a red shift of absorption in comparison with the dipropoxy derivative and ANT. In contrast, in ANTs, the dipropoxy derivative exhibited a red shift of absorption and fluorescence in comparison with the tetrapropoxy derivative and ANT. The electronic effects of alkoxy substitution could be explained by TD-DFT calculations.