Synthesis and Crystal Structures of Bis(diallydithiocarbamato)zinc(II) and Silver(I) Complexes: Precursors for Zinc Sulfide and Silver Sulfide Nanophotocatalysts

We report the preparation and crystal structures of bis(diallydithiocarbamato)zinc(II)and silver(I) complexes. The compounds were used as single-sourceprecursors to prepare zinc sulfide and silver sulfide nanophotocatalysts.The molecular structure of bis(diallydithiocarbamato)zinc(II) consistsof a dimeric complex in which each zinc(II) ion asymmetrically coordinateswith two diallydithiocarbamato anions in a bidentate chelating mode,and the centrosymmetrically related molecule is bridged through theS-atom that is chelated to the adjacent zinc(II) ion to form a distortedtrigonal bipyramidal geometry around the zinc(II) ions. The molecularstructure of bis(diallydithiocarbamato)silver(I) formed a clustercomplex consisting of a trimetric Ag3S3 moleculein which the diallydithiocarbamato ligand is coordinated to all theAg(I) ions. The complexes were thermolyzed in dodecylamine, hexadecylamine,and octadecylamine (ODA) to prepare zinc sulfide and silver sulfidenanoparticles. The powder X-ray diffraction patterns of the zinc sulfidenanoparticles correspond to the hexagonal wurtzite while silver sulfideis in the acanthite crystalline phase. The high-resolution transmissionelectron microscopy images show that quantum dot zinc sulfide nanoparticlesare obtained with particle sizes ranging between 1.98 and 5.49 nm,whereas slightly bigger silver sulfide nanoparticles are obtainedwith particle sizes of 2.70-13.69 nm. The surface morphologiesof the ZnS and AgS nanoparticles capped with the same capping agentare very similar. Optical studies revealed that the absorption bandedges of the as-prepared zinc sulfide and silver sulfide nanoparticleswere blue-shifted with respect to their bulk materials with some surfacedefects. The zinc sulfide and silver sulfide nanoparticles were usedas nanophotocatalysts for the degradation of bromothymol blue (BTB)and bromophenol blue (BPB). ODA-capped zinc sulfide is the most efficientphotocatalyst and degraded 87% of BTB and 91% of BPB.

Automated summary

The preparation and crystal structures of bis(diallydithiocarbamato)zinc(II) and silver(I) complexes were reported. These compounds were used as single-source precursors to prepare zinc sulfide and silver sulfide nanophotocatalysts. The resulting nanoparticles exhibited excellent performance in terms of light absorption and the degradation of bromothymol blue and bromophenol blue.