Synthetic, X-ray structural and protonation studies of CpCr(CO)2SPy and CpCr(CO)2SPym (SPy = C5H4NS, SPym = C4H3N2S)

The facile reaction of [CpCr(CO)3]2 (Cp = η5-C5H5) (1) with one mole equivalent of 2,2′-dithiodipyridine ((C5H4NS)2triple bond; length of mdash(SPy)2) at ambient temperature led to the isolation of dark brown crystalline solids of CpCr(CO)2(η2-SPy) (2) in ca. 72% yield. 2 undergoes quantitative conversion to CpCrCl2(η1-SPyH) (3) with HCl. The reaction 1 with one mole equivalent of 2-mercaptopyrimidine (C4H3N2SHtriple bond; length of mdashHSPym) at ambient temperature led to the isolation of reddish-brown crystalline solids of CpCr(CO)2(η2-SPym) (4) and green solids of CpCr(CO)3H (5) in yields of ca. 42% and 46%, respectively. Reaction of 4 with HCl and subsequent workup in acetonitrile resulted in the cleavage of the thiolate ligand, giving the 15-electron chromium(III) species CpCrCl2(CH3CN) (6) and free 2-mercaptopyrimidine. The complexes 2–4 have been determined by single X-ray diffraction analysis.