A novel mixed-ligand manganese(II) complex containing a V-shape water trimer:: Synthesis, structure and magnetic properties of {[Mn(azpy)2(dca)(H2O)2](ClO4)(azpy)(H2O)2}n

A novel mixed-ligand complex {[Mn(azpy)(2)(dca)(H2O)(2)](ClO4)(azpy)(H2O)(2)}(n) (1) has been synthesized and characterized by single crystal X-ray analysis, elemental analysis, IR spectroscopy and variable temperature magnetic measurement. The 4,4'-azopyridine and dicyanamide ligands are abbreviated as azpy and dca, respectively. The crystal structure of 1 revealed that the 1 D covalent bonding chains constructed by mu(1,5)-dca bridging the Mn-II ions are linked together via O-H center dot center dot center dot N and O-H center dot center dot center dot O hydrogen bonds and pi-pi stacking interactions into a 3D supramolecular structure. V-shape (bent) water trimers were also found in the structure. The water clusters play an important role in the formation of the 3D supramolecular structure. The determination of the variable temperature magnetic susceptibilities (2-300 K) shows the existence of a very weak antiferromagnetic interaction with a J value of -0.16 cm(-1).