Syntheses, structures and photoluminescent properties of cadmium(ii), silver(i) and copper(i) complexes with novel long chain tetradentate ligands

Abstract

Two new coordination complexes [Cd(L1)Br₂] (1) and [Ag₃(L1)₂](ClO₄)₃ (2) were obtained by assembly reactions of CdBr₂ and AgClO₄ with long chain tetradentate ligand 1,6-bis(4-imidazol-1′-ylmethylphenyl)-2,5-diazahexane (L1). X-Ray diffraction analyses reveal that complex 1 is composed of neutral 2D grid networks, which are further linked by N–H⋯Br and C–H⋯Br hydrogen bonds to produce a 3D framework. Complex 2 with four- and two-coordinated silver(I) atoms has a double-stranded wandering chain structure formed by Ag–N coordination, Ag⋯Ag and π–π interactions. Complexes [Ag(L2)]NO₃ (3), [Cu(L2)]ClO₄ (4) and [Cu(L2)]BF₄ (5), with a relatively rigid long chain Schiff base ligand 1,6-bis(4-imidazol-1′-ylmethylphenyl)-2,5-diaza-1,5-hexadiene (L2), exhibit infinite 1D zigzag chain structures. The results show that the structure of the assemblies is predominated by the nature of organic ligands and the geometric requirements of metal ions. The photoluminescent properties of the synthesized complexes were studied in the solid state at room temperature.