摘要:
The reaction of Pb(2+) ions with 4-thiazolidinone-2-thione (Hrd) yields to coordination of the uncommon dilead unit (Pb(2)(2+)) by the N-deprotonated molecule of the ligand. The powder structure determination of the complex reveals an almost planar dimeric structure with the {N,S} coordination mode. The intermolecular distance of the Pb-Pb moiety (3.51(4) angstrom) is lower than the van der Waals parameter suggesting the formation of a bond. The structure in the solid state and DFT calculations of molecular orbitals and the presence of a bond critical point between the lead atoms clearly demonstrate the existence of a single bond within the Pb-Pb unit formed by the 6p orbital electrons. The lone pairs of the 6s orbitals do not participate in bonding with the ligand atoms and are likely bisdirected. FT-IR and FT-Raman spectra confirm the molecular structure since all the modes of the NH group disappear in the spectra of the complex, while the stretching mode of the C=S bond shifts to lower values, as would be expected for this coordination fashion. (C) 2011 Elsevier B.V. All rights reserved.