BINARY [HYDROTRIS(1,2,4-TRIAZOLYL)BORATE]METAL COMPLEXES [M(HB(C2H2N3)3)2] WITH M=FE, CO, CU, ZN - SYNTHESIS, CHARACTERIZATION, MAGNETOCHEMISTRY, AND X-RAY STRUCTURE OF [CU(HB(C2H2N3)3)2.4CH3OH AND K[HB(C2H2N3)3].2H2O

The bis[hydrotris(1,2,4-triazolyl)borate] metal complexes [M{HB(C2H2N3)3}2] with M = Fe (5), Co (6), Cu (7), Zn (8) are obtained from MX2 and K[HB(C2H2N3)3] (9). The complexes are characterized by IR, UV/Vis, and MS. Temperature-variable magnetic measurements show a Curie-Weiss behavior for the paramagnetic complexes 6 and 7 with a temperature-dependent magnetic moment for 6. The iron complex 5 exhibits a spin crossover from diamagnetic to paramagnetic, starting at around 270 K. Single-crystal X-ray structures of the solvates 7 . 4 CH3OH and 9 . 2 H2O have been determined. The structure of 7 . 4 CH3OH shows the Jahn-Teller distorted copper complex 7 surrounded by methanol molecules through hydrogen bonding to exocyclic nitrogen atoms of the tris(1,2,4-triazolyl)borate ligand. The crystal system for 7 . 4 CH3OH is monoclinic, space group P2(1)/n. Compound 9 . 2 H2O is a one-dimensional coordination polymer with the potassium atom bridged by the water molecules and the tris(1,2,4-triazolyl)borate ligand and crystallizes in the orthorhombic space group Ccm2(1).