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

Abstract

Oxidation of the surface-capping SPh ^- ligands of the CdS cluster [S ₄ Cd ₁₀ (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 nm. 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 Å diameter. The isolated material redissolved in DMF where its emission spectrum showed a strong broad band at 510 nm.