Synthesis and crystal structures of Pb(II) dithiocarbamates complexes: precursors for PbS nanophotocatalyst

摘要

Pb(II) complexes of N-ethyl-N-phenyl dithiocarbamate [Pb(EtPhdtc)(2)] and N-benzylmethyl dithiocarbamate [Pb(BzyMedtc)(2)] were synthesized and characterized by single crystal X-ray crystallography. The molecular structures of compounds reveal a distorted tetrahedral geometry around the Pb(II) ions. [Pb(EtPhdtc)(2)] crystalized as a dimeric structure with (PbPb)-Pb- horizontal ellipsis and (PbS)-S- horizontal ellipsis interactions while [Pb(BzyMedtc)(2)] crystallized as monomeric complex with weak C-H interactions. Thermogravimetric analysis of the Pb(II) complexes shows they decomposed to give lead sulphide (PbS). The complexes were thermolysed in oleic acid (OA) at 120 degrees C, 160 degrees C and 200 degrees C to study the influence of temperature on OA capped PbS nanoparticles. Powder X-ray diffraction patterns confirms that the as-prepared PbS are cubic rock salt crystalline phase of PbS. High resolution transmission electron microscopy (HRTEM) micrographs crystallite average size of 2.64 nm for particles prepared at 120 degrees C, 4.12 nm for particles prepared at 160 degrees C, and 1.93 nm for particles prepared at 200 degrees C from [Pb(EtPhdtc)(2)]. The average crystallite sizes of PbS nanoparticles obtained from [Pb(BzyMedtc)(2)] are 6.61 nm at 120 degrees C, 13.88 nm at 160 degrees C, and 10.82 nm at 200 degrees C. The as-prepared PbS nanocrystals were used as photocatalyst for the degradation of methylene blue with the highest degradation efficiency of 73.89% recorded for OAPbS1a.