Synthesis and hydrolysis of thiol derivatives of molybdocene dichloride incorporating electron-withdrawing substituents

Hydrolysis studies of derivatives of molybdocene dichloride in which the two chloride ligands were replaced by 3,5-bis(trifluoromethyl)thiophenol, 3,5-bis(trifluoromethyl)benzyl thiol, and 2,2,2-trifluoro-ethane thiol ligands confirmed that the electron-withdrawing groups affect the lability of the Mo-S bonds and promote slow generation of the putative biologically active species "Cp₂Mo²⁺"; the trifluoroethane thiol derivative underwent 50% hydrolysis in 14 h in 10% D₂O/DMSO-d₆. The structure of molybdocene bis(S-3,5-bis(trifluoromethyl)benzyl thiol) was confirmed by X-ray crystal structure analysis.