Synthesis, characterization and crystal structures of dinuclear macrocyclic Schiff base copper(I) complexes bearing different bridges

• Published in: Polyhedron 2010-11, Vol.29 (17), p.3178-3182
• Main Authors: Khandar, Ali Akbar, Butcher, Ray J., Abedi, Marjan, Hosseini-Yazdi, Seyed Abolfazl, Akkurt, Mehmet, Tahir, M. Nawaz
• Format: Article
• Language: English
• Subjects: 20-Membered macrocyclic Schiff base; Benzene-1,3-dicarboxaldehyde; Dicopper(I) complexes; Halogen-bridged complexes; X-ray structure
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2010.08.031

The synthesis, characterization and crystal structures of three dinuclear Cu(I) complexes of a 20-membered [2+2] macrocyclic, N 4 donor, Schiff base ligand, containing different halogen bridges are described. The stacking and hydrogen bonds of the crystal structures and the role of bridging groups in controlling the Cu⋯Cu separation have been investigated. Utilizing a new 20-membered macrocyclic Schiff base ligand with two coordination sites formed from the [2+2] condensation of 1,3-diaminopropane and benzene-1,3-dicarboxaldehyde in the presence of CuX (X = Cl −, Br −, I −) salts, air-stable dicopper(I) complexes were synthesized in acetonitrile, intramolecularly linked via two halide groups, and characterized by different physico-chemical techniques. The single crystal X-ray diffraction technique indicates these complexes consist of two N 2X 2 donor sets that have distorted tetrahedral coordination environments around the copper(I) ions. In these halogen-bridged binuclear Cu 2LX 2 systems the Cu⋯Cu separation can be controlled, as this distance is reduced on increasing the halide size and hence the X⋯X repulsion, with the rigidity of the macrocycle playing a significant role.