The reaction of hexacarbonyl group 6 complexes with the P(CH)P ligand N,N′-bis(diisopropylphosphino)-N,N′-dimethyl-1,3-diaminobenzene was investigated. The objective was to obtain PCP pincer complexes via directed C-H bond activation and cleavage. In the case of chromium and molybdenum, complexes [Cr(κ3P,CH,P-P(CH)PNMe-iPr)(CO)3] and [Mo(κ3P,CH,P-P(CH)PNMe-iPr)(CO)3], featuring η2-Caryl-H bonds, were formed and no C-H bond cleavage took place. With tungsten the expected seven-coordinate hydrido carbonyl W(II) complex [W(κ3P,C,P-PCPNMe-iPr)(CO)3H] was formed. DFT mechanistic studies corroborate the experimental observations and indicate that the M-H bond strength grows in the order Cr-H < Mo-H < W-H, explaining the preference for the hydride complex only in the case of W. X-ray structures of these complexes are presented.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry