Synthesis, Structure, and Electronic Properties of (eta-C5Me5)2 V(Micron-OC) V(CO)5. A Complex with a Linear V-O-C-V Bond

摘要

The reaction between V(CO)6 and (eta-C5Me5)2V yields the mu-isocarbonyl complex, I(eta-C5M35)2V(mu-OC)V(CO)5. Crystals of I belong to the space group C2/c. An important aspect of the structure is the linear V-O-C-V moiety with V-O = 2.075 (4) A, C-0 = 1.167 (6) A, and V-C = 1.899 (5) A. Complex I is a paramagnetic, contains two unpaired electrons, and obeys the Curie law between 5 and 298 K. SCC-Xalpha-DV calculations of (eta-C5H5)2V(mu-OC)V(CO)5 show that nearly degenerate frontier orbitals localized on the (eta-C5H5)2V+ fragment lead to a high-spin 3B1 ground state. The V-O bond arises mainly from an electrostatic interaction between (eta-C5Me5)2V+ and V(CO)6-, however, a small covalent Pi back-donation from a d(t sub 2g) orbital on V(CO)6- into a partly occupied b sub 1 Pi orbital on the (eta-C5H5)V+ fragment is observed. Photolysis of I as well as its thermal reaction with carbon monoxide in solution yields ETA-C5Me5)2V(CO)2V(CO)6.