Synthesis and Structure of a Ni(II)-Cu(II)-Ni(II) Trinuclear Complex With a New Macrocyclic Complex Ligand 

Xiao-Zeng Li,a* Jun-Hong He,a and Dai-Zheng Liaob
a Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China. E-mail:
Department of Chemistry, Nankai University, Tianjin 300071, P. R. China

A trinuclear complex, [Cu(NiL)2(NCS)2], was prepared by the reaction of a new macrocyclic oxamido complex ligand NiL, Cu(ClO)2∙6H2O and KNCS. L denotes the doubly deprotonated form of dimethyl 5,6,7,8,15,16-hexahydro-15-methyl-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate. Excess Cu(ClO)2∙6H2O is necessary for the formation of the title compound. The structure of the title complex was further characterized by X-ray single-crystal analysis. Cu(II) and each Ni(II) is bridged by the oxamido group from the corresponding macrocyclic ligand. The coordination geometry around each Ni( = 2 \* ROMAN II) ion is slightly distorted square planar with N4 donor set, and the Cu(II) ion has a distorted octahedral coordination geometry of O4N2 donor set. π∙∙∙π interactions and CH∙∙∙O hydrogen bonds link the molecules to form two-dimensional supramolecular layers.  

Key words: synthesis, crystal structure, macrocyclic compound, complex ligand, Ni( = 2 \* ROMAN II)-Cu( = 2 \* ROMAN II)-Ni( = 2 \* ROMAN II) complex