Syntheses, structures and magnetic properties of two new water bridged dinuclear nickel(II) complexes containing derivatives of 1,2,4-triazole and pivalate ligands

Two new water bridged dinuclear nickel(II) complexes containing derivatives of 1,2,4-triazole and pivalate ligands, [Ni-2(mu-H2O)(Vadmtrz)(2)(PiV)(4)(H2O)(2)](.) 13H(2)O (1(.) 13H(2)O) (admtrz = 4-amino-3,5-dimethyl- 1,2,4-triazole, piv = pivalate anion) and [Ni-2(mu-H2O)(V-adetrz)(2)(PiV)(4)] (.)3H(2)O (2 (.) 3H(2)O) (adetrz = 4-amino-3,5-diethyl- 1,2,4-triazole) were prepared and structurally characterized. Both I and 2 have similar unprecedented dinuclear Ni(II) units with one water and two triazole bridges, in which each six-coordinated Ni(II) ion is further coordinated with terminal pivalate ligand and in the case of I also two terminal water molecules. Variable temperature magnetic susceptibility measurements for the powder samples of I and 2 in the range of 1.8-300 K show that weak antiferromagnetic interactions occur in 1 and 2. Theoretical fit of the magnetic data gave g = 2.198, D = -10.03 cm(-1), and J= -6.88 cm(-1) for 1 and g = 2.143, D = -12.31 cm(-1), and J= -5.63 cm(-1) for 2. (c) 2006 Elsevier Ltd. All rights reserved.