Hindered rotation of some substituted thioureas in complexes of chromium and tungsten carbonyls

Synthesis and Characterization of Molybdenum(0) and Tungsten(0) Complexes of Tetramethylthiourea: Single-Source Precursors for MoS2 and WS2

“…Given the documented utility of [M(CO) 6 ] (M = Mo and W) to serve as precursors to MS 2 in the presence of sulfur sources such as H 2 S, , we judged that carbonyl complexes of Mo and W containing TMTU ligands would provide the ideal combination of ease of handling and low thermal stability desired in a single-source precursor. Examples of group VI carbonyl complexes featuring thiourea or imidazolethione ligands have been known for several decades. − The vast majority of such compounds are of the form [M(CO) 5 L], although Cotton reported the synthesis of the tris-thiourea complex, fac -[Mo(CO) 3 ­{SC(NH 2 ) 2 } 3 ], in 1962 . Despite this extensive history, no comprehensive single study has examined the chemistry of a family of group VI carbonyl complexes containing a common thiourea ligand.…”