Tetranuclear Nickel(II) and Cobalt(II) Complexes with 3,5-Dimethyl-1-pyrazolylmethanolato and Acetato Bridges Having a Cubane Core

Abstract

Tetranuclear nickel(II) and cobalt(II) complexes with μ₃-O-3,5-dimethyl-1-pyrazylmethanolato (dmpm) and μ-O,O′-acetato, [M₄(dmpm)₄(O₂CCH₃)₄]·2CH₃CN (M = Ni, Co), were isolated. The crystal structures were determined by the single-crystal X-ray diffraction method at 90 K. Both of the structures are isomorphous in the tetragonal space group P4₂/n with a = 11.5812(11)Å, c = 16.580(2)Å, V = 2223.8(4)ų, D_x = 1.459 g/cm³, and Z = 2 for the nickel(II) complex; these values are a = 11.608(2)Å, c = 16.717(4)Å, V = 2252.4(7)ų, D_x = 1.555 g/cm³, and Z = 2 for the cobalt(II) complex. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0288 and 0.0842, and 0.1046 and 0.2786, for the former and the latter, respectively. Each complex has a cubane-like tetranuclear M₄O₄ core with octahedral NO₅ geometry; the closest Ni…Ni separation is 2.9750(4)Å, or the Co…Co separation of 3.0433(19)Å.