Preparation and characterization of macrocyclic dinickel complexes coligated by tetrazolate ligands

The dinuclear nickel(II) complex [Ni2LCl](+) (1), where (L)(2-) represents a 24-membered macrocyclic hexamine-dithiophenolate ligand, reacts readily with 5-R-tetrazolate ligands to give the complexes [Ni2L(RCN4)](+), where R = H (2), Me (3), Ph (4). The new complexes were either isolated as perchlorate or tetraphenylborate salts and fully characterized by elemental analysis, UV/Vis, and IR spectroscopy. The structures of 2[BPh4] . MeCN, 3[BPh4] . 2MeCN, and 4[BPh4] - MeCN were determined by X-ray crystallography, showing that all tetrazolate units are in a 2,3-bridging mode to generate dioctahedral N3Ni(mu-S)(2)(mu-N4CR)NiN3 core structures. The RCN4- groups interact less strongly with the [Ni2L](2+) fragment than pyrazolate ligands (CH)(3)N-2(-) as reflected in the longer Ni-N distances.