Nonanuclear Coordination Compounds Featuring {M9L12}6+ Cores (M = NiII, CoII, or ZnII; L = 1,2,3‐Benzotriazolate)

Abstract

AbstractSyntheses, characterization, and magnetic properties of three nonanuclear coordination compounds with the molecular formulae [Ni9(bta)12(NO3)6(MeOH)6]·4THF (1) (btaH = 1,2,3‐benzotriazole; THF = tetrahydrofuran), [Co9(bta)12(MeOH)18][(NO3)6]·9C6H6 (C6H6 = benzene) (2), and [Zn9(Me2bta)12(CH3COO)6]·3DMF (Me2btaH = 5,6‐dimethyl‐1,2,3‐benzotriazole; DMF = N,N′‐dimethylformamide) (3) are presented. The solid‐state structures of all the compounds were determined by single‐crystal X‐ray structure analysis revealing the presence of structurally similar {M9L12}6+ cores (M = NiII, CoII, or ZnII; L = 1,2,3‐benzotriazolate) in which the metal centers are bridged by μ3‐benzotriazolates. The charges of the cationic {M9L12}6+ moieties in 1 and 3 are balanced by six nitrate and acetate anions coordinated to the peripheral metal atoms, respectively, whereas 2 is a cationic metal complex with six noncoordinated nitrate counterions in the crystal lattice. All the metal centers in each compound are hexacoordinate, except for the peripheral metal centers in 3 which are pentacoordinate. The nonanuclear cores can be formally subdivided into two metallosupramolecular tetrahedra which bear five metal ions each, and share a common apex. All compounds have been prepared by using excess of ligand, which acts as an auxiliary base, serving to abstract protons from the coordinated benzotriazole ligand. Magnetic susceptibility studies (2–290 K) show net antiferromagnetic intramolecular coupling for 2, while 1 displays both ferro‐ and antiferromagnetic coupling contributions. Both compounds exhibit strong ligand field effects in their magnetic properties. Phase purity of the compounds was ascertained by X‐ray powder diffraction (XRPD) analysis, IR spectroscopy, and elemental analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)