Three different configurations of d10 complexes based on benzoxazole pyridyl ligand: Synthesis, structures and properties

Three different coordination complexes containing 2-(3'-pyridyl)-benzoxazole (3-PBO) and 2-(4'-pyridyl)-benzoxazole (4-PBO) ligands, namely [Cd(3-PBO)(2)(NO3)(2)(H2O)(2)]CH3CN [Zn(4-PBO)(2)(NO3)(2)] (2) [Ag(4-PBO)(2)Pic[(n), (Pic = Picric acid) (3) have been synthesized and characterized. Single crystal X-ray structure analysis reveals that complex 1 is distorted seven-coordinated pentagonal-bipyramidal geometry, and complex 2 is a twisted six-coordinate octahedral structure, while complex 3 is a four -coordinated one-dimensional linear coordination polymer. A wide range of hydrogen bonding (of the O-H center dot center dot center dot O and O-H center dot center dot N types) and pi-pi stacking interactions are also present in the crystal structure. These arrangements lead to the formation of three supramolecular structures. By careful inspection of the structures of 1 and 2, the ion radius of metal centers adopting various coordination modes is a crucial factor for the formation of the different structures. Cyclic voltammograms of 3 indicate a quasi-reversible Ag+/Ag couple. Moreover, the fluorescence properties of the ligands and complexes 1-3 were studied in solid state. Strong photoluminescence is observed in complexes 1 and 2 at room temperature and the complexes may be good candidates for potential luminescence materials. (C) 2017 Elsevier Ltd. All rights reserved.