Synthesis, characterization and X-ray crystal structures of seven-coordinate pentagonal-bipyramidal zinc(II), cadmium(II) and tin(IV) complexes of a pentadentate N3S2 thiosemicarbazone

The complexes, [M(H2dap4NMetsc)(H2O)2](NO3)2·H2O (M = Zn2+, Cd2+; H2dap4NMetsc = 2,6-diacetylpyridinebis(4N-methylthiosemicarbazone) and [Sn((dap4NMetsc)Ph2] (dap4NMetsc = the doubly deprotonated form of 2,6-diacetylpyridine bis(4N-methylthiosemicarbazone) are seven-coordinate and the coordination environment around each metal ion is a distorted pentagonal-bipyramid.