Synthesis and structural characterisation of three dicyanamide complexes with Mn(II), Zn(II) and Cd(II): Supramolecular architectures stabilised by hydrogen bonding

Three new dicyanamido, [N(CN)(2)](-) (dca) compounds of the formula [Mn(ac)(tptz)(dca)(H2O)]center dot(H2O)(2) (1), [Zn(tptz)(dca)(2)]center dot(H2O)(2) (2) and [Cd-2(tPtz)(2)(dca)(2)(H2O)(2)]center dot(ClO4)(2) (3), (where ac = acetate anion and tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) have been synthesised. X-ray diffraction analysis revealed that the manganese atom in 1 is seven-coordinated with a pentagonal-bipyramidal environment, in 2 zinc is penta-coordinated square pyramidal and in 3 the cadmium atom is six-coordinated octahedral. dca is found to act as an end-to-end bridging ligand in the dimer 3, whereas in I and 2 it acts as a monodentate terminal ligand. All the complexes exhibit supramolecular architectures by hydrogen bonding interactions involving lattice water (for I and 2) or coordinated water molecules (for 3)