Structural and spectral studies of a heterocyclic N(4)-substituted bis(thiosemicarbazone), H 22,6Achexim·H 2O, its heptacoordinated tin(IV) complex [Bu 2Sn(2,6Achexim)], and its binuclear zinc(II) complex [Zn(2,6Achexim)] 2

Abstract

The multidentate ligand, 2,6-diacetylpyridine bis(3-hexamethyleneiminylthiosemicarbazone) monohydrate, H 22,6Achexim·H 2O, crystallizes with one thiosemicarbazone moiety in an intramolecular hydrogen bonded, bifurcated E′ form. The other thiosemicarbazone moiety is E and is not involved in intramolecular hydrogen bonding, but is involved in hydrogen bonding with the hydrate water molecule. The dianion (loss of N3a and N3b hydrogens) of H 22,6Achexim acts as a pentadentate ligand, 2,6Achexim, in a planar conformation to a central tin(IV) ion, and as a bridging tetradentate ligand with the two thiosemicarbazone moieties of 2,6Achexim coordinating to different zinc atoms. The tin(IV) is heptacoordinate in a distorted pentagonal dipyramidal configuration, with the five SNNNS donor atoms of 2,6Achexim in the pentagonal plane and the two n-butyl groups in the axial positions. The binuclear zinc complex has two equivalent tetrahedral zinc centers, with the pyridyl nitrogens of the two ligands not coordinated.