We synthesyzed partially-overlapped bromocarbazolophanes.

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Reaction of guaiazulene with 1,2-di(2-thienyl)-1,2-ethanediol in methanol in the presence of sulfuric acid at 333 K for 1 h gives 2-(3-guaiazulenyl)-1,1-di(2-thienyl)ethylene (1), (E)-2-(3-guaiazulenyl)-1,2-di(2-thienyl)ethylene (2) and (Z)-2-(3-guaiazulenyl)-1,2-di(2-thienyl)ethylene (3). Furthermore, reaction of 1 with TCNE in benzene at 298 K for 24 h under argon affords 1,1,2,2,11,11,12,12-octacyano-8-isopropyl-3,3-bis(2-thienyl)-5,10-dimethyl-6,9,10a-trihydro-6,9-ethanobenzo[a]azulene (4). Moreover, reactions of 1 and 2 with TCNE in DMF at 298 K for 24 h under argon give 2-(3-guaiazulenyl)-1-(2-thienyl)-1-[2-(5-tricyanovinyl)thienyl]ethylene (6) from 1 and (E)2-(3-guaiazulenyl)-2-(2-thienyl)-1-[2-(5-tricyanovinyl)thienyl]ethylene (7) from 2. The crystal structures as well as the spectroscopic, electrochemical and chemical properties of the above products are discussed.

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Hexadehydrotribenzo[12]annulene ([12]DBA) which consists of mixed sp-sp²-hybridized system is expected to show different redox behavior from sp²-hybridized systems. In this report, we synthesized novel [12]DBA derivatives possessing amino group as an electron-donating group and cyano group as an electron-accepting group. We systematically investigated the electronic effects of substituents on the [12]DBA backbone from both the redox potentials obtained by electrochemical measurements of these compounds and theoretical calculations. It was found that the amino substituted [12]DBA showed irreversible redox behavior. Moreover, we found that it generated the corresponding radical cation species by chemical oxidation.

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We have studied synthesis and properties of novel, non-planar extended quinones aimed for molecular-switching function since we found the reversible photoisomerization between the quinone-structure and diradical-structure of dibenzoannelated 3,5,3'',5''-tetra-tert-butylterphenoquinone. To improve the photo-switching properties of the extended quinones, we designed a quinone having dendrimer structure (1) as a new target. Light-harvesting properties and unique environment of dendrimer would affect photoreactivities of the core quinone. We here report our synthetic approach toward the dendrimer 1. After several trial of synthetic methods, we prepared the third-generation isomer of 1 at present. Synthesis of compounds up to the fourth-generation and properties of them will be report.

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Tetrakis(5-(2-thienyl)-2-thienyl)methane (2a) and tetrakis(5-(5-(2-thienyl)-2-thienyl)-2-thienyl)methane (3a) have been synthesized from tetrakis(2-thienyl)methane (1a) by Suzuki coupling as a key reaction. The tetrakis(trimethylsilyl) derivatives (1b-3b) substituted at 5-positions of the terminal thienyl groups of 1a-3a are also synthesized. These compounds show the good solubility in THF, methylene choride and chloroform. The longest absorption maximum of 1a-3a shows the bathochromic effect by 10-20 nm compared with that of the corresponding oligothiophenes. Trimethylsilyl groups cause the bathochromic effect along with the increase of the molar absorption coefficient.

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In this study, we developed a simple and novel process for the formation of benzene ring-layered polymers, which consists of aligned benzene rings, by a palladium-catalyzed coupling reaction of pseudo-p-diethynyl[2.2]paracyclophane, 2,7-di-tert-butyl-4,5-diiodo-9,9-dimethylxanthene. Synthesis, characterization, stereochemistry, and optical properties of the obtained polymers will be discussed in detail.

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5-Ehynyltropolone having aryl ring moiety as the substituent; the non-bezeboid tolan type compounds, can be expected to show an interesting interaction between the toropolone ring and aryl ring moiety. We regard the toroponoid tlan type compunds as a potential chromophore. In addition, these molecules can easily produce transition metal complexes. We describe here the syntheses and the properties of 5-[(9-anthryl)ethynyl]tropolone, 5-[(1-anthryl)ethynyl]tropolone, 5-[(1-naphthyl)ethynyl]tropolone, and 5-phenylethynyltropolone and their metal complexes.

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The development of novel chromogenic organic host molecules has attracted much attention because of their potentiality of application to analytical and material sciences. In this work we have synthesized the new host molecules 1 and 2 containing two salicylideneamine structures within a molecule and investigated properties of their inclusion crystals. In these molecules three tautomeric structures and possible : diketo (KK), ketoenol (KE), and dienol (EE) forms arising from keto-enol type tautomerism on the two salicylideneamine moieties. The X-ray analysis revealed that in inclusion crystals of 2.(CH₂Cl₂)₂, 2 exists as the KK form. while in 1.(acetone), 1 has the structure intermediate between EE and KK forms. Further attempts to prepare the sulfur analog 3 are in progress.

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1,3-Di-tert-butylazulene reacts with highly electrophilic trifluoromethanesulfonate of N-containing heterocycles to give 5-(dihydroheteroaryl)azulene derivatives in good yield and treatment of the 5-(dihydroheteroaryl)azulene derivatives with KOH afforded 5-(heteroaryl)azulenes in excellent yield.

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Bisacridinium Derivatives with Chiral Amide Groups Exhibiting Multi-input and Multi-output Response

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In electronic absorption and emission spectra of meta-phenylene-type phenol oligomers, not only phenol form but also phenoxide form (conjugate base) is observed. Roughly, intensity ratio of phenol and phenoxide in the absorption spectra was nearly unchanged when the oligomer length n is higher than 3, in accord with their almost identical acid dissociation constant. On the other hand, the intensity ratio was significantly changed depending on n in the emission spectra. The different chain-length dependence will be discussed by referring to acid dissociation constants in the excited state, which are estimated by the Forster cycle.

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Molecular Response Systems Based on the Dynamic Redox Behavior of 2,2'-Bipyridine Derivatives

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In nature, supramolecular architecture and allosteric interactions are one of the important factors that control of biological structures and functions, respectively. Formation of biological supramolecular polymers, such as actin filament, is based on a cooperative nucleation-elongation process. The initial oligomerization of monomer is energetically disfavored relative to the subsequent chain propagation into a long filament. Hydrindacenediamide 1 is the exoditopic receptor that can bind two benzenediol guests on both sides of molecule in a positive homotropic allosteric manner. We report here construction of supramolecular copolymers driven by a positive allosteric binding with resorcinol units. The supramolecular copolymers were formed upon admixing of 1 with the resorcinol dimers 2 to give crystalline precipitates or highly viscous oil. The X-ray structural analysis of the former solid revealed the formation of one-dimensional supramolecular strand.

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We have studied dynamic behavior of 1,8- and 9,10-anthrylene-acetylene cyclic oligomers incorporated with various aromatic rings. We found that oligomers with a phenylene or a 1,5-naphthylene unit underwent rapid rotation of the aromatic ring. We report the synthesis and structure of this type of oligomer with a 1,5-anthrylene unit. This aromatic unit was introduced into the cramp-like acyclic trimer by desilylation and Sonogahira reaction to restrict the rotation of the unit. The 1H NMR spectra gave signals expected for a C2 symmetric structure, and this signal pattern was retained at 140 C.

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Conformational control of molecular tweezers having a disulfide bond of an alkyl ring is presented. The tweezers having the disulfide bond adopted the cleft conformation by the intramolecular CH/pi interaction between the alkyl chain and the terminal naphthalene rings. When the disulfide bond of the alkyl ring was broken, the structure was changed to have the stepped conformation. The thiol-disulfide redox reaction readily proceeded to control the conformation of the tweezers.

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A tunable chiral host system was developed by the self-assembly of a chiral 2₁-column structure formed from (1R, 2R)-1,2-diphenylethylenediamine and dicarboxylic acid. This host system can include guest molecules by changing the packing of a chiral 2₁-column enantioselectively.

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We prepared the dendron with a rigid conjugated chain and flexible dendric chains.2,2'-Bipyridyl groups were incorporated in terminals of both the conjugated and dendritic chains to control a conformation of flexible chains by metal complexations. An attachment of dendritic branches and an extension of phenylacetylenic units were alternatively manipulated on the substituted diphenylacetylene using a combination of Suzuki- and Sonogashira cross-coupling reactions. The dendron was mixed with FeCl2 at room temperature in CHCl3-DMSO(1:1) to form [Fe(II)(bpy)3]2+ complex as well as the absorption of the dendron at 287, 257 nm. The detailed synthetic procedure and properties of the dendron will be presented.

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Cholic acid (CA) and its derivatives form inclusion compounds with chiral compounds. The guest molecules are often included in channel-like chiral cavities created by the host molecules. We have studied chiral recognition of various alcohols and amines in the inclusion compounds of CA derivatives. Ammonium salts of CA were prepared by mixing the CA and 1-phenylethylamine derivatives at a 1:2 molar ratio and recrystallized from methanol to prepare single crystals for X-ray crystallography. A single X-ray crystallography revealed crystal structures of CA, DCA and LCA with 1-(4-chlorophenyl)ethylamine (a), 1-(4-bromophenyl)ethylamine (b) and 1-(4-methylphenyl)ethylamine (c). Crystal structures of DCA and LCA with three amines showed selective inclusion of R-isomer, and CA with two amines, (b) and (c), showed selective inclusion of R-isomer. While crystal structure of CA with (a) showed selective inclusion of S-isomer. We report that CA recognized chirality of amines.

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Recently, a variety of heteroatom-bridged calixarenes has been synthesized, which exhibits peculiar properties different from the parent calixarenes. To develop a novel and versatile host molecule, we are studying the structure-property relationships of azacalixarene composed of phenol rings and nitrogen bridges, the latter of which serve as additional hydrogen-bonding and functionalization sites. Very recently, we have succeeded to prepare azacalix[n]arene methyl ether (n = 6 and 8) with no substituents on the nitrogen bridges. In this conference, preparation and molecular structure of them with bifurcated NH...O hydrogen bonds will be reported.

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Novel [2]catenanes successfully synthesized through a 34-crown-10 and bipyridinium units attaching on a rigid calix[4]arene. Both their dynamic behavior and circular dichroism altered after changing the length of the linkages.

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Ethynylpyridine oligomers, which are consisted of pyridine rings linked by acetylene bonds at 2,6-positions, associate with saccharides by multipoint hydrogen bondings to form helical structure. The helical sense of the complexes is biased by the chirality of the guest saccharides to show characteristic induced CDs at the absorptive region of ethynylpyridines. Previously, we reported glucose-linked ethynylpyridine oligomer, of which glucose moiety is binded by covalent bonding at the end. Herein we report syntheses of various types of saccharide-linked ethynylpyridine oligomers and studied the relationship of the helical higher-ordere structures with the primary structures based on the CD and NMR spectroscopy.

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Crowded triarylphosphine-quinone oligomers carrying phosphine moieties similar to tris(2,4,6-triisopropylphenyl)phosphine were synthesized by employing Suzuki coupling as a key reaction. ³¹P NMR spectra of the oligomers reflect distribution of the diastereomers arising from helicity of the propeller composed by three aromatic rings substituted on the phosphorus. UV-vis spectroscopy and cyclic voltammetry revealed that these crowded triarylphosphines carrying quinones, which display purple to blue color, exhibit corresponding charge-transfer absorption which blue-shifted as the difference between the oxidation potential of the phosphine moieties and the reduction potential of the quinone moieties becomes larger.

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The synthesis of Ph5Te-Li+(DME)3 was achieved by the reaction of freshly prepared Ph4Te with PhLi. After exchange of the solvent from THF to DME of the mixture, Ph5Te-Li+(DME)3 was obtained as yellow-orange solid. All manipulations were carried out at -78 C. The single crystals were grown from DME at low temperature and X-ray crystallographic analysis was performed at -173 C. The molecular structure indicates that the Ph5Te- has square-pyramidal (pseudo octahedral) structure around the tellurium and the Te-C (basal) bond lengths (2.329-2.342 A) are longer than the apical Te-C bond length (2.153 A). The isolated hypervalent anion is relatively stable at -30 C in the solid state. Structural details of Ph5Te-Li+(DME)3 and behavior in a solution will also be discussed.

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We advance the origin of physical properties of ⁷⁷Se NMR chemical shift and the research is advanced aiming at the establishment of the analytical method that can be understood as the experimental chemist is intuitive. This time, the origin of ⁷⁷Se NMR chemical shift was clarified from the above-mentioned standpoint. In the process, it proposes the effect of pre-alpha in addition to alpha, beta, and the gamma effect that has been often discussed up to now. The effect of pre-alpha was made a starting point, alpha, beta, and the gamma effect, etc. were analyzed, and it succeeded in the visualization. The result is announced.

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The photochemistry of the title diazaparacyclphane has been investigated. Upon irradiation of the cyclophane, a polycyclic photoproduct which possessed a octahedrane skeleton was obtained. This is the first photochemical formation of octaherane, namely, through the photodimerization of benzene.

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Recently, much attention has been focused to titanium oxide as a photocatalyst. Photoirradiation of titanium oxide excites the electrons from valence band to conduction band, leaving holes in the valence band. Using the holes, it is possible to perform a one-electon oxidation, and using the electron, it is also possible to do a one-electron reduction. So we attempted to use the electron for one-electron reduction in perfluoroalkyl iodide and to combine the one-electron-oxidation of nucleophile for the introduction of perfluoroalkyl group into nucleophile. However, the balance of the ability of oxidation and reduction in titanium oxide was not good, and the decomposition of the iodide did not proceed efficiently. In this conference, we would like to report the effects of MeOH and lithium or sodium salt as additives to promote the reduction efficiently.

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The relative reactivities of substituted benzophenones with borane have previously been determined by the competition experiments and Hammett value has been reported to be -0.12. In the present study, we measured the rates of borane reduction of substituted benzaldehydes and bezophenones by a stopped-flow method and compared the substituent effects with those determined by the competition experiments.

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Among various rearrangement reactions, a reaction in which two atoms or atomic groups migrate in one step is extremely rare and the mechanism is not well understand. In this study, we took intramolecular double hydrogen shift reactions of acyloin derivatives, and calculated the reaction pathway of the proton and hydride migration by a quantum mechanical method. We found two kinds of transition states, whose relative energy varies with substituent. We will discuss these transition state structures and the substituent effects in detail.

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Since many solvent molecules are around the solute molecules in solution, it is necessary to take account of free energy, i.e. not only enthalpy but also entropy. To evaluate how solvent molecules affect the reaction profile, we calculated the free energy changes along the exchange reaction path for X-+RX+100H₂O (R=Me, Et, i-Pr, t-Bu X=F, Cl). We calculated two-dimensional free energy surfaces to search the reaction path in aqueous solution.

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The spiropyrans are the thermal reversibility of the colored open form generated by the UV irradiation to the colrless closed form. However, some of the spiropyrans shows the negative photochromism. The closed form of 1'3'-dihydro-3'3'-dimethyl-6-nitro-3,1'-propanospiro[2H-1-benzopyran-2,2'-[2H]indole] is highly strained. So in protic sovent, such as ethanol, the colored open form is more stable than the colorless closed form. Pressure and viscosity effects on the negative photochromism in protic solvent (ethanol and 2-methylpentane-2,4-diol (MPD)) and the photochromism in aprotic solvent (methyl acetate and glycerol triacetate (GTA)) were studied. Both photochromism and negative photochromism process were retarded with increasing pressures. In highly viscous solvents, MPD and GTA, viscosity induced retardation was observed at higher pressures.

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Pressure effects on the fading reaction of the title compound generated by UV irradiation were measured in ethanol and 2-methylpentane-2,4-diol (MPD). In ethanol, the reaction was accelerated with increasing pressures. In highly viscous MPD, however, viscosity induced retardation was observed at higher pressures. The dynamics of solvent reorganization will be discuss on the basis of pressure and viscosity effects of title compound compared with those of napthopyrans and 2,2-dimethylbenzopyran.

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(E)-Bis(pentafluorophenyl)[2-(phenylazo)phenyl]borane (1) and (E)-[2-(4-methoxyphenylazo)phenyl]bis(pentafluorophenyl)borane (2) were synthesized. Irradiation of 1 and 2 in the solution state caused strong green fluorescence. The fluorescence quantum yields of 1 and 2 at r.t. in hexane were determined to be 0.23 and 0.76, respectively, which are extremely high compared with the unsubstituted azobenzene and the latter of which is higher than any azobenzene derivatives reported previously. Synthesis of other azobenzene derivatives and the theoretical calculations will be also reported.

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In this study, we have investigated the nucleophilicities of alcohols and related compounds toward highly reactive diarylmethyl cations in acetonitrile solution using a laser flash photolysis technique. For each nucleophile log k_N increased linearly with decreasing electrophilicity of diarylmethyl cations. Using log k = s(N+E) proposed by Mayr, the nucleophilicity N values were determined. It was found that the N value decreases in the order of MeOH > EtOH > i-PrOH > t-BuOH in similar to the solvent nucleophilicty. Although this order is not consistent with the change in the basicity of alcohols, the N values for MeOH, n-PrNH₂, and CF₃CH₂NH₂ are linearly correlated with gas-phase basicity, suggesting that low nucleophilicities of i-PrOH and t-BuOH arise from steric effect.

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Photophysical and photochemical properties of oligosilanes were widely investigated; however, intramolecular interaction between oligosilane chromophores in the ground and excited states remains open. 1,3-Bis(permethyldecasilanyl)propane 1 was prepared to investigate the intramolecular interaction between decasilane moieties. Although the UV absorption of 1 was almost similar to that of mono-chromophoric permethyldecasilane (3), new emission band was observed besides weak normal emission of decasilane in the fluorescence spectrum of 1. The emission indicated that the two decasilane-chromophores interacted each other in the excited state.

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Rotaxanes are defined as interlocked molecular compounds with significantly different properties from those of their individual components. Herein, we wish to report the first synthesis of organosilicon rotaxanes. The cleavage of Si-C bridged bond of a macrocyclic disilaalkanes 1 using triflic acid at mild conditions, followed by methylation using MeMgBr afforded target rotaxane 2 in 71% isolated yield, along with free dumbbell-shaped compound 3 in a minor yield (eq. 1). This is the first application of protodesilylation reaction to the synthesis of rotaxane. Structure of rotaxane 2 was fully characterized by NMR spectroscopy. Hydrolysis after protodesilylation of 1 gave silicon-functionalized rotaxane 4 in 42% yield.

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Recently, we reported a novel cyclization of electron-deficient cyclopentadienone(1) with 2-alkynylamines and propargyl alcohols via sequential pericyclic reaction pathway, in which the reaction proceeded via initial fomation of the 1,4-adducts followed by the ene cyclization and/or sequential pericyclic reactions depending upon the structures of the amines and alcohols.
In order to apply ene/IMDA reaction to unsaturated compounds, reactivity of alkynyl alkyl ketones were investigated. The reaction of 1 with 2 in benzene gave the DA adducts, whereas in the presence of catalytic amounts of amine gave the cyclization products via 1,4 addition. The reaction mechanism is discussed on X-ray analysis and MO calcurlation data.

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NMR Quantum Informatino Processing by Phosphorus Compounds.

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The rate constant (k_H) of hydride transfer from an NADH analog, 9,10-dihydro-10-methylacridine (AcrH₂), to 1-(p-tolylsulfinyl)-2,5-benzoquinone (TolSQ) increases with increasing Sc³⁺ concentration ([Sc³⁺]) to reach a constant value. When AcrH₂ is replaced by the dideuterated compound (AcrD₂), however, the rate constant (k_D) increases linearly with an increase in [Sc³⁺]. On the other hand, the rate constant of Sc³⁺-promoted electron transfer from tris(2-phenylpyridine)iridium to TolSQ also increases linearly with increasing [Sc³⁺]. This indicates that the reaction pathway is changed from one-step hydride transfer from AcrH₂ to the TolSQ-Sc³⁺ complex to Sc³⁺-promoted electron transfer from AcrD₂ to the TolSQ-Sc³⁺ complex.

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Nitronyl nitroxides with trans- and cis-stilbene skeletons and some transition metal complexes of the radicals were synthesized in expectation of their spin alignment through pi-pi stacking interactions. The susceptibility data of the metal complexes revealed some ferromagnetic interactions, and their intra- and inter-chain interactions were analyzed on the basis of the X-ray crystallographic data.

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Recently, we constructed the single-molecule magnet by using a heterospin system, consisting of the 3d spin of the cobalt ion and the 2p spin of the organic spin source. This time, we prepared new salicylaldehyde derivatives carrying aminoxyl radical for the purpose of using as a counter anion carrying organic spin and revealed its molecular structure. Using this new ligand, the metal complexes were synthesized and revealed molecular structures. Magnetic properties of these metal complexes will be reported.

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In order to achieve photo-responsive super-high spin organic compounds, preparations and magnetic properties after irradiation of dendritic polymers having diazo groups connected by diphenylacetylenes were investigated in this work. Polyketone precursor of the polydiazo polymer was prepared by Sonogashira reaction of core triiodo compound and branched diiodoethynyl compound followed by reaction with terminating tetraalkyloxy compound. Components having molecular weight larger than about 3 x 10³ was separated by GPC and was used in following experiments. The polyketone polymer was converted to polydiazo polymer by the usual method through hydrazone compound. Magnetic properties after photolysis of the polydiazo polymers in 2-MTHF frozen solutions were investigated by SQUID. The curve fitting for the field dependence of magnetization at 5 K provided the average spin multiplicities of the photoproducts as S = 6.3.

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Synthesis and properties of novel cross-conjugated tetrathiafluvalene-type donors

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A new (2:1) complex consisting of Cu(hfac)₂ and 4-amino-TEMPO was found to form by reacting TEMPO derivatives with a benzylideneamine core with Cu(hfac)₂, which acts as a Lewis acid to hydrolyze the core and incorporates the resulting 4-amino-TEMPO as a ligand. We then prepared several related Mn(hfac)₂ complexes by using 4-amino-TEMPO or bis-TEMPO-substituted ethylenediamine as the ligand and the structures and their properties will be reported.

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Starting from TEMPO-substituted pyridinium fluoroborate, some of the corresponding Ni(dmit)₂, Pd(dmit)₂, and Ni(mnt)₂ salts were prepared. Among them, the corresponding salt with (1:6) radical cation-to-anion ratio was obtained by oxidation of the Ni(dmit)₂ or Pd(dmit)₂ salt, showing semi-conductive property with relatively high room temperature conductivity. The structures and magnetic properties of the radical salts prepared will be reported.

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A series of one dimensional triamine with various substituents at the central aromatic ring were designed and synthesized. Electrochemical and novel electron transfer stopped-flow (ETSF) methods were invoked for characterizing the absorption spectra of the corresponding short-lived mono- and dicationic states. Useful molecular design rules for stabilizing the di and tricationic states were elucidated.

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Phenalenyl based closed shell compounds with small HOMO-LUMO energy gap have been studied in our laboratory. Recently, we revealed the singlet biradical character of these compounds and their unique properties resulting from the biradical character. Compounds with benzoquinoid and naphthoquinoid structure along with two phenalenyl rings have been studied to clarify the relationship between biradical character and properties. This time, we succeeded in the synthesis of compound 1 having anthraquinoid structure along with two phenalenyl rings. Electronic absorption spectrum of 1 gave a lower energy band than compounds with benzoquinoid and naphthoquinoid structure. Considering the shape of HOMO and LUMO of 1, this result supports the large biradical character of 1.

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For elucidation of electronic spin structures, and intra- and intermolecular magnetic interactions within and between pi-conjugation system(s), it is crucially important to develop novel stable neutral radicals. We have recently started to investigate stable neutral radicals linked with corannulene, a hydrocarbon with a curved pi-conjugation network, and already synthesized and isolated corannulene derivatives with some neutral radicals. And, we have revealed that the spin of phenoxyl derivative is more larger delocalized into the curved pi-surface than that of 6-oxoverdazyl and iminonitroxide derivatives. More recently, we have designed a corannulene derivative substituted with a t-butyl nitroxide radical moiety as a new stable neutral radical. In this work, we have successfully synthesized and isolated it. ESR/ENDOR/TRIPLE and DFT calculations revealed that the spin densities were widely spread over the curved-surface as same as those of phenoxyl derivative.

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In order to prepare organic magnetic materials, we have studied persistent high-spin polycarbenes. As a part of this research, 9-acrydyl(phenyl)diazomethane was synthesized and triplet carbene generated by photolysis of this diazo compound was characterized by spectroscopic means. Magnetic properties of photoproducts from a complex of 9-acrydyl(phenyl)diazomethane N-oxide and copper ion is also described.

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Synthesis, structure and magnetic property of novel carboranyl radicals.

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