Crystal structure and properties of the precursor [Ni(H2O)6](HTBA)2·2Н2О and the complexes M(HTBA)2(H2O)2 (M = Ni, Co, Fe)

Four new compounds, the discrete complex [Ni(H2O)6](HTBA)2·2Н2О (1) and three coordination polymers M(H2O)2(HTBA-O,S)2, M = Ni (2), Co (3) and Fe (4), were synthesized and structurally characterized. Blue single crystals of 1 precipitate in solution at 5-20 °C as a precursor to 2 then quickly decompose into the yellow powder Ni(H2O)2(HTBA)2 (2).