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

ABSTRACT

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 Pb^…Pb and Pb^…S 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°C, 160°C and 200°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°C, 4.12 nm for particles prepared at 160°C, and 1.93 nm for particles prepared at 200°C from [Pb(EtPhdtc)₂]. The average crystallite sizes of PbS nanoparticles obtained from [Pb(BzyMedtc)₂] are 6.61 nm at 120°C, 13.88 nm at 160°C, and 10.82 nm at 200°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.

GRAPHICAL ABSTRACT

KEYWORDS:

• Pb(II) dithiocarbamates
• crystal structures
• lead sulphide
• structural properties
• optical properties
• photocatalysis

Acknowledgements

The authors are grateful to National Research Foundation and SASOL South Africa for the research grant award.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Peter A. Ajibade http://orcid.org/0000-0002-8581-2387