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The present paper deals with the microstructural parameters calculated from X-ray diffraction data, electrical and optical investigations, and scanning tunneling microscopy (STM) studies on ZnIn2S4 IIIa layer type CdIn2S4-xSex (1.75 ≤ x ≤ 2.75) quaternary chalcogenides. Microstructural parameters such as dislocation density, root-mean-square strain, stacking fault probability, crystallite size anisotropy, and layer disorder parameters of these compounds have been calculated. The temperature variation of electrical conductivity (25−400 °C) confirmed semiconducting behavior. The band gaps of all these compounds obtained from STM and optical measurements are in the range 1.57−1.77 eV and are comparable to each other irrespective of the technique used.

The synthesis of dicyanooligothiophenes NC(C4H2S)nCN (n = 3−6) is reported. For n = 3, 4, and 5 the dinitriles are generated by treatment of the corresponding dibromo compounds with copper(I) cyanide in quinoline. For n = 6 the preparation involves the Ni-catalyzed coupling of 5-bromo-2,2‘:5‘,2‘‘-terthiophene-5‘‘-carbonitrile. The structures of all four dicyano derivatives have been determined by X-ray crystallography. For n = 3, the space group is monoclinic C2/c, with a = 18.363(7), b = 11.8356(9), c = 30.666(4) A, β = 102.15(2)°, V = 6515(3) A3, Z = 20. For n = 4 the space group is triclinic P1, a = 7.3254(9), b = 7.8658(6), c = 8.1813(8) A, α = 64.706(8), β = 76.059(8), γ = 76.692(8)°, V = 409.29(7) A3, Z = 1. For n = 5 the space group is monoclinic C2/c, with a = 13.633(4), b = 11.706(5), c = 37.073(8) A, β = 90.22(2)°, V = 5929(3) A3, Z = 12. For n = 6, the space group is monoclinic P21/a, with a = 13.8962(14), b = 5.9100(16), c = 14.0798(16) A, β = 98.446(4)°, V = 1143.8(4) A3, Z = 2. In all four ...

Electroreduction of 1,3- and 1,4-benzene-bridged bis(diselenadiazolium) salts [1,4-Se][SbF6]2 and [1,4-Se][SbF6]2 in acetonitrile, at a Pt wire and in the presence of iodine affords the 1:1 charge-transfer salts [1,4-Se][I] and [1,3-Se][I]. Crystals of [1,4-Se][I] belong to the monoclinic space group C2/m, with FW = 598.9, a = 10.586(2), b = 16.713(2), c = 3.5006(14) A, β = 104.26(2)°, V = 600.2(3) A3, Z = 2. Crystals of [1,3-Se][I] belong to the orthorhombic space group Ima2, with FW = 598.9, a = 28.489(7), b = 3.543(2), c = 12.283(2) A, V = 1239.8(8) A3, Z = 4. In the presence of an excess of iodine, electrocrystallization of [1,4-Se]2+ affords the mixed iodide/triiodide salt [1,4-Se][I][I3], space group C2/c, FW = 979.59, a = 12.862(3), b = 15.063(2), c = 9.028(3) A, β = 100.62(2)°, V = 1719.1(7) A3, Z = 4. The structures of the two 1:1 compounds consist of perfectly superimposed stacks of molecular units interspersed by columns of disordered iodines. Interstack contacts in both structures are limited,...

Cosublimation of 2,5-furanbis(1,2,3,5-dithiadiazolyl) [F-2,5-S] and iodine affords 1:1 and 2:1 charge-transfer salts, [F-2,5-S][I] and [F-2,5-S]2[I]. Cosublimation of 2,6-pyridinebis(1,2,3,5-dithiadiazolyl) [P-2,6-S] and iodine affords uniquely the 2:1 charge-transfer salt [P-2,6-S]2[I]. Crystals of the latter belong to the space group P21/c, a = 3.434(3), b = 9.8914(9), c = 30.803(4) A, β = 91.52(3)°, V = 1045.9(9) A3, Z = 2. The structure consists of [P-2,6-S] molecules stacked along the x direction. Pairs of stacks are linked head-on through iodine atoms, which themselves form disordered stacks running parallel to x. The internal structural parameters of the two CN2S2 rings within each molecule suggest that one (linked to iodine) is formally uncharged, while the other is partially oxidized. This latter ring is heavily coordinated through S- - -N linkages to neighboring CN2S2 rings and pyridine. Magnetic susceptibility measurements on [P-2,6-S]2[I] indicate that it is diamagnetic below 220 K.