Discrimination between S2? and SO2? Sites in Mixed Crystal Compounds Containing Co and Co/Mo Clusters by 59Co-NMR Spectroscopy, and the Relevance for HDS Catalysis

Abstract

In aqueous solutions of the mixed crystal compounds with formal composition K8[Co4?xMoxS4?y(SO)y(CN)12·nH2O (x = 0–2; y = 0–2) i) there are distinct CoS, Co(SO), and Co(SO)2 sites and ii) no hetero-metal clusters are present. These results, revealed by 59Co–NMR, could principally not be disclosed by single crystal X-ray structure analysis. The NMR data also suggest a stable dinuclear cobalt-sulphur cluster in solution. The relevance for HDS catalysis is discussed.