SYNTHETIC AND STRUCTURAL CHEMISTRY OF NICKEL(II) 1-METHYLBENZOTRIAZOLE COMPLEXES

A systematic investigation of the NiX2/Mebta (X = Cl, Br, NCS, NO3; Me bta = 1-methylbenzotriazole) reaction system in various solvents is de scribed. Particular emphasis has been placed on determining the influe nce of the Mebta:Ni(II) ratio on the identity of the reaction products . In the nitrate case, the influence of the water concentration in the reaction mixture on reaction products has also been investigated. The se combined variations have led to the preparation of 14 discrete six- coordinate complexes with the formulae [Ni(NO3)2(Mebta)2], [Ni(NO3)(H2 O)2(Mebta)2]NO3, [Ni(H2O)4 (Mebta)2](NO3)2, [Ni(NO3)2(Mebta)3].CH3COCH 3, [NiX2(Mebta)4](X = ONO2, NCS, Cl, Br), [NiX2(Mebta)2]n (X = Cl, Br) , [NiX2(MeOH)2(Mebta)2] (X = Br, NCS) and [NiX2 (Mebta)]n (X = Cl, Br) . Four complexes have been structurally characterized by single-crysta l X-ray studies: cis-[Ni(NO3)2(Mebta)2] (1), trans-[Ni(H2O)4(Mebta)2]( NO3)2 (3), mer-[Ni(NO3)2(Mebta)3].CH3COCH3 (4) and trans-[Ni(NCS)2(MeO H)2(Mebta)2] (6). Mebta behaves as a monodentate ligand binding throug h N(3). The structures of 3 and 6 are stabilized by intermolecular hyd rogen bonds. The new complexes were studied by thermal techniques, con ductivity measurements, magnetic susceptibilities and spectroscopic (I R, ligand field) methods. Monomeric, trans pseudo-octahedral structure s are assigned for the complexes [NiX2(Mebta)4] and [NiBr2(MeOH)2(Mebt a)2] in the solid state. Polymeric structures are suggested for [NiX2( Mebta)2]n and [NiX2(Mebta)]n with NiX4N2 and NiX5N coordination sphere s, respectively.