Solid state coordination chemistry of cobalt(II) with carboxyphenyltetrazoles

The hydrothermal reaction of the appropriate Co(II) salt and 3- or 4-carboxyphenyltetrazole yielded the molecular [Co(3-trzphCO2H)2(H2O)4] (2) and the three-dimensional phases [Co(3-trzphCO2)] (3), [Co(4-trzphCO2)(H2O)] (4), and [Co(SO4)(OH)(3-trzphCO2H)] (5). The compounds exhibit a range of tetrazolate bonding motifs, including monodentate in 2, bidentate bridging in 3, bridging to three cobalt sites in 4 and bridging four cobalt sites in 5. The three-dimensional connectivities of 3–5 are achieved through the additional linkages provided by the carboxylate groups. The secondary building units include Co-tetrazolate chains in 3, Co-tetrazolate double chains in 4 and {Co3(tetrazolate)3(OH)}2+ trinuclear units in 5.