Unusually Weak Metal−Hydrogen Bonds in HV(CO)4(P−P) and Their Effectiveness as H• Donors
摘要:
The V-H bonds in HV(CO)(4)(P-P) are unusually weak (55 to 58 kcal/mol). They transfer H center dot to styrene more rapidly than CpCr (CO)(3)H does and are effective stoichiometric reagents for the cyclization of appropriate 1,6-dienes.
The preparation and properties of η3-cycloalkenylcarbonylvanadium complexes of the following types are reported: (η3-enyl)V(CO)5, (η3-enyl)V(CO)4PR3 (R = Et, Ph) and (η3-enyl)V(CO)3L2 (L2 = dppe (1,2-bis(diphenylphosphino)ethane), dppm (bis(diphenylphosphino)methane), arphos (1-diphenylphosphino-2-diphenylarsinoethane); L = PPh3).