Preparation of a novel CdS nanocluster material from a thiophenolate-capped CdS cluster by chemical removal of SPh- ligands

Oxidation of the surface-capping SPh- ligands of the CdS cluster [S4Cd10(SPh)(16)](4-) in solution has been explored as a route to the-synthesis of larger, well defined nanocrystals of CdS. Iodine was found to oxidise and remove the SPh- ligands and effect the growth of a CdS cluster with a sharp UV-VIS absorption peak at 371 mm. Electrospray mass spectra indicate that the first step in the transformation involves the loss of the four [Cd(SPh)(4)] units at the cluster corners. Characterisation by FTIR; and UV-VIS spectroscopy and X-ray powder diffraction showed that the material consists of iodide-capped clusters of approximately 15 Angstrom diameter. The isolated material redissolved in DMF where its emission spectrum showed a strong broad band at 510 nm.