In search of molecular precursors for cadmium sulfide—new complexes with a sulfur-rich kernel: cadmium(ii) tri-tert-butoxysilanethiolates with additional diethyldithiocarbamato ligand

Abstract

The reaction of dimeric bis(tri-tert-butoxysilanethiolato)cadmium(II) [Cd{SSi(OBu^t)₃}₂]₂1 with diethyldithiocarbamate sodium salt in the presence of quaternary ammonium salts resulted in formation of three new heteroleptic cadmium(II) complexes—the first silanethiolate species possessing additionally other S-donor ligands. Neutral 2 as well as ionic compounds 3 and 4 can be obtained with a good yield depending on the quaternary salt and solvent used. Their X-ray structures have been determined—complex [Cd{SSi(OBu^t)₃}(S₂CNEt₂)]₂2 turned out to be dimeric in the solid state, while 3 and 4 are monometallic species with a [Cd{SSi(OBu^t)₃}₂(S₂CNEt₂)]⁻ anion. The cadmium atom in each case has been found tetra-coordinated with a distorted CdS₄ kernel. Elemental and spectral analyses (IR, NMR, UV-vis) were carried out. Thin films of 2 and 3 prepared on SiO₂ substrates viaspin coating technique were analysed by AFM and XPS. The thermal decomposition product of 2 was analysed using XRD, EDS, SEM and TEM measurements and identified as hexagonal CdS.