Electrical and optical properties of copper and nickel molecular materials with tetrabenzo [b,f,j,n] [1,5,9,13] tetraazacyclohexadecine thin films grown by the vacuum thermal evaporation technique.

Semiconducting molecular-material thin-films of tetrabenzo (b,f,j,n) [1,5,9,13] tetraazacyclohexadecine copper(II) and nickel(II) bisanthraflavates have been prepared by using vacuum thermal evaporation on Corning glass substrates and crystalline silicon wafers. The films thus obtained were characterized by infrared spectroscopy (FTIR), atomic force microscopy (AFM), ultraviolet-visible (UV-vis) spectroscopy and ellipsometry. IR spectroscopy showed that the molecular-material thin-films exhibit the same intra-molecular bonds as the original compounds, which suggests that the thermal evaporation process does not significantly alter their bonds. The optical band-gap values calculated from the absorption coefficient may be related to non-direct electronic interband transitions. The effect of temperature on conductivity was also measured in these samples. It was found that the temperature-dependent electric current is always higher for the nickel-based material and suggests a semiconductor-like behavior with conductivities in the order of 10(-8)Omega(-1)cm(-1).

Formation of a novel trinuclear spirostannoxane tin(IV) compound. Crystal and molecular structure of [Sn(nBu)(Cl)[(OCH2CH2S)2Sn(nBu)]2] and the stannolane [(nBu)Sn(SCH2CH2O)SCH2CH2OH].

The reaction of nBuSnCl3 and the sodium salt of 2-mercaptoethanol (1:1) in ethanol gave the compound Sn(nBu)(Cl)[(OCH2CH2S)2Sn(nBu)]2 (1). [(nBu)Sn(SCH2CH2O)SCH2CH2OH] (2) was initially isolated from the reaction of 1 with nBuMgCl as a rearrangement product but was also synthesized from nBuSn(O)OH and two molar equivalents of 2-mercaptoethanol. Both compounds were characterized by means of IR, 119Sn, 13C, and 1H NMR, FAB mass spectroscopy, and elemental analyses. The structures were determined by single-crystal X-ray diffraction. 1 crystallizes in the monoclinic Cc space group (a = 18.492(3) A, b = 17.329(2) A, c = 10.787(1) A, beta = 111.88(1) degrees, Z = 4), while 2 crystallizes in the orthorhombic Pbca space group (a = 14.458(2) A, b = 10.393(1) A, c = 16.479(2) A, Z = 8). 1 is a trimetallic Tin(IV) compound in which the central atom is in 6-fold coordination, while the two remaining tin atoms show 5-fold coordination. Both pentacoordinated tin atoms are bonded to a butyl group and to the oxygen and the sulfur atoms from two [OCH2CH2S]2- ligands forming two stannolanes, which are fused with the hexacoordinated tin atom forming a distannoxane system. This arrangement is quite different from previous ladder or staircase structures. NMR data point to maintenance of this structure in solution. 2 consists of [(nBu)Sn(SCH2CH2O)(SCH2CH2OH)] units, which are associated via intermolecular Sn-O interactions building up a dimer. The tin atom forms two "stannolane" units by interaction with [OCH2CH2S]2- and [HOCH2CH2S]- ligands.