μ<inf>3</inf>-Methoxido-κ³ O:O:O-tris(μ-l-p- tyrosinato-κ³ N,O:O)tris(l-p-tyrosinato-κ² N,O)trinickel(II,III) methanol tetrasolvate

Abstract

A trinuclear nickel complex, [Ni3(C9H 10NO3)6(CH3O)]·4CH4O, was synthesized and characterized as a neutral cluster containing the incomplete cubane {Ni 3(μ1-O)(μ2-O)2(μ3-O)} core of 2M3-1 topology. The three nickel cations show similar octahedral coordination, {Ni(μ1-O)(μ2- O)2(μ3-O)(μ1-N)2}; the positive charge is balanced by six tyrosinate ligands and one methoxide ion. The mean oxidation state of each NiII ion is therefore +2.33. The common coordination modes, chelating (via the amino N and the carboxylate O atoms) and bridging (via the carboxylate O atom), are exhibited by the tyrosinates. Three interligand (intracluster) N - H⋯O hydrogen-bonding interactions stabilize the incomplete cubane-type moiety. Additional N - H⋯O, O - H⋯O and C - H⋯O interactions are formed between clusters, and between the clusters and methanol molecules to regulate the spatial orientation of the tyrosinate and the assembly of the clusters in the crystal. The approximate equilateral triangular arrangement of the three nickel cations in the incomplete cubane-type moiety suggests the possible magnetic frustration, and the proximity of these metal cations indicates weak metallic bonds. The structure contains approximately 39% solvent-accessible volume between the clusters. This is filled with 17 molecules of disordered methanol and was modelled with SQUEEZE [Spek (2009). Acta Cryst. D65, 148-155]; the reported unit-cell characteristics do not take these molecules into account. The H atoms of the solvent molecules have not been included in the crystal data.