Synthesis, structure and magnetism of a hydrogen-bond-linked three-dimensional network of a novel nickel(II)–cobalt(II)–nickel(II) complex containing a new macrocyclic mononuclear complex ligand

A novel trinuclear complex, [Co(NiL)2(H2O)2](ClO4)2 · 2C2H5OH, was prepared by self-assembly using [NiL] as a new complex ligand; L is the dianion of dimethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate. The structure of the trinuclear complex was determined by X-ray crystallography. The CoII ion is at the center of the trinuclear complex cation and occupies a distorted octahedral O6 environment, approximating to Oh with a 4T1g ground state for CoII that has an unquenched spin–orbit coupling reflected in the magnetic properties. Two NiII ions reside in completely same and slightly distorted square-planar N4 coordination geometries. CoII and each NiII are bridged by an oxamido group from one of the two macrocyclic ligands (L). O—H...O and π...π interactions link the trinuclear fragments, perchlorate ions and C2H5OH molecules to form a three-dimensional supramolecular architecture.