摘要:
The reactions of a series of 5-alkyl-2-thiophenedithiocarboxylates with nickel(II) chloride afforded two types of complexes, blue nickel(II) complexes with two terminal dithiocarboxylate ligands, [Ni(S2CTR)(2)] and violet nickel(II) complexes with perthio- and dithiocarboxylate ligands, [Ni(S2CTR)(S3CTR)] (where T = 2,5-disubstituted thiophene, R = CnH2+1, n = 4,6,8,12,16). The blue monomers are preferred for the shorter chains (C-4 and Q and the violet compounds form exclusively for the longer chains (C-8, C-12, and C-16) in the alkylthiophene complexes. In addition to the above series, [Ni(S-2,CTCH3)(2)], was prepared in a one-pot reaction in THF and both the blue and violet products were isolated. It was possible to convert the blue complexes [Ni(S2CTR)(2)] (R = butyl, hexyl) into the corresponding violet complexes [Ni(S3CTR)(S3CTR)] after stirring in THF solutions for prolonged periods of time. Liquid-crystalline properties of these complexes were examined by DSC and POM. The violet complexes with Cs and C12 alkyl chains showed liquid-crystalline properties. (c) 2007 Elsevier Ltd. All rights reserved.