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Reactions of 4,4-diphenyl- and 4,4-di(p-tolyl)dithienosilole with tetracyanoethene (TCNE) in DMF gave coupling products 4,4-diphenyl- and 4,4-di(p-tolyl)-2-(tricycanoethenyl)dithienosilole (1a and 1b) in good yield. The films of 1b exhibited vapor-chromism, and the color of the film changed from red to blue-purple upon exposure to the vapor of organic solvents such as ethanol, methanol, acetonitrile, ethyl acetate, acetone, and hexane. The color reverted to the original red upon contact with chloroform vapor, indicating that this process is reversible.

Starlike molecules with arms consisting of a tert-butyldimethylsilyloligothienylenedimethylsilyl unit, MeSi[SiMe2(T)nSiMe2(t-Bu)]3 (7−11; n = 2−6, T = thienylene) were prepared by the reactions of tris(chlorodimethylsilyl)methylsilane, which was chosen as a core, with the tert-butyldimethylsilyl-substituted lithiooligothienylenes used for construction of the arms. UV−visible absorption and fluorescence properties of 7−11 have been studied in a dioxane solution. The molecules 7−11 showed high fluorescence quantum yields with respect to the corresponding oligothiophenes. Compounds 7 and 8 revealed longer lifetimes than those of bi- and terthiophene. The results of X-ray crystallographic analysis of the bromo derivative 12 are described. The density functional theoretical calculations were also carried out to compare the geometrical structures and the excitation energies with the available experimental data.

Polymers with alternating mono-, di-, or trisilanylene units and 2,5-oligothienylene groups, [(SiR2)x(C4H2S)m]n (R = Me, Et, x = 1−3, m = 2−5), were synthesized and their optical, conducting, and hole-transporting properties were investigated. The UV absorption and emission maxima of the polymers shift to lower energies as the number of thienylene groups (m) between the silanylene units increases, while they are little affected by the silicon chain length (x). When the polymer films were exposed to FeCl3 vapor, semiconducting films with the conductivities of 1.3 × 10^-4−2.3 × 10^-1 S/cm were obtained. The conductivities tend to increase with m but decrease with increasing x. The double-layer-type EL devices were fabricated using some of the polymers (x = 1, m = 3−5; x = 2, m = 4) as the hole-transporting layer and tris(8-quinolinolato)aluminum(III) (Alq) as the electron-transporting-emitter layer. Reducing the number of m and x resulted in a high-voltage shift in the turn-on voltage and a decrease in the maximum current density of the device. The highest luminance of 2000 cd/m² was obtained from a device based on the disilanylene−tetrathienylene alternating polymer (x = 2, m = 4).

A series of bithiophene derivatives bearing an intramolecular monosilanylene or disilanylene bridge between the β,β‘-positions were synthesized, and their properties were investigated. UV spectral and cyclic voltammetric analyses of the silicon-bridged bithiophenes indicated that they have lower lying LUMOs, relative to those for bithiophene and methylene bridged bithiophenes, probably due to σ*−π* interaction between the silicon atom(s) and bithiophene π-orbitals, in good agreement with the results of theoretical calculations using simplified model compounds based on RHF/6-31G. The silicon-bridged bithiophenes exhibit high electron-transporting properties, and triple-layer-type electroluminescent (EL) devices, using the silicon-bridged bithiophenes, tris(8-quinolinolato)aluminum(III) complex (Alq), and N,N‘-diphenyl-N,N‘-di-m-tolylbiphenyl-4,4‘-diamine (TPD) as the electron-transporting, emitting, and hole-transporting layers, respectively, emitted strong EL.

Electrode reaction of ammoniated electrons was investigated with voltammetry, potentiometry and chronoamperometry. Experiments were conducted on Pt, Au and W electrodes in 0.5 M LiI, NaI, KI, CsI and KBr solutions of liq. NH3. The results in dilute solutions (< 10<−4M) do not reflect the differences in alkali metal, electrode metal and supporting electrolyte and are explained by a simple one‐electron transfer process whose transferring species is a free solvated electron and its ion‐pair with a metal cation in a rapid equilibrium. The formal standard potential is −2.155 ± 0.005 V vs. Pb/Pb(NO3)2(0.05 M) at −40°C in liq. NH3involving 0.5 M alkali metal iodide. The lower limit of the averaged diffusion coefficient is 0.7 × 10−4cm2s−1. At higher metal concentrations (> 10−2M), a two‐electron transfer process tends to prevail, which is explained by considering the dimer of ion‐pairs as the diffusing species.

Electronic structure of interfaces between 5,10,15,20-tetraphenylporphynatozinc (ZnTPP) and four metals (Mg, Al, Ag, and Au) were studied by ultraviolet photoelectron spectroscopy (UPS). The energy levels of ZnTPP relative to the Fermi level of substrate metals could be expressed as linear functions of the work function of metals with the shift of the vacuum level at interface (Δ). The slope of the linear functions was about unity. This indicates that the energy levels of ZnTPP are fixed to the vacuum level of substrate metal with constant interfacial dipole. 5,10,15,20-Tetra(4-pyridyl)porphyrin (H 2 T(4-Py)P)/metal and 5,10,15,20-tetraphenylporphyrin (H 2 TPP)/metal interfaces were also investigated, and similar linearity was observed between the energy levels of porphyrin and the work function of metal with the slope of much smaller than unity. This deviation of the slope from unity might be explained by the existence of interface state.