NICKEL(II) COMPLEXES OF 1,7-BIS(BENZIMIDAZOL-2-YL)-2,6-DITHIAHEPTANE (BBDHP) - CRYSTAL AND MOLECULAR-STRUCTURE OF [NI2(BBDHP)2(MU-CL)2]CL2.5H2O.2ETOH AND NI(BBDHP)BR2.ETOH.1 2BU(T)OH/

The synthesis and characterization by elemental analyses, mass, IR and electronic spectrometry and conductance and magnetic measurements of compounds with the general formula Ni(BBDHP)X 2 . nSolv. is reported [ X = Cl, Br, I, ClO4 or NO3; Solv. = H2O, EtOH or ButOH; n = 2-5; BBDHP = 1,7-bis(benzimidazol-2-yl)-2,6-dithiaheptane]. The structures of [N i(BBDHP)(mu-Cl)]2Cl2.5H2O.2EtOH (II) and Ni(BBDHP)Br2.EtOH.1/2ButOH (I V) were determined by single-crystal X-ray diffraction. A molecule of II exhibits a dimeric structure involving two approximately symmetrica l chlorine bridges. In both complexes the nickel atom has an octahedra l environment with cis coordination of the two halide ligands [av. Ni- Cl = 241.6(1), av. Ni-Br = 256.9(9) pm] and the BBDHP in a symmetrical -cis arrangement [av. Ni-S = 243.6(2), av. Ni-N = 207.1(4) pm]. In bot h compounds the crystal packing is governed mainly by hydrogen bonds i nvolving benzimidazole groups, halide atoms and water molecules.