STUDY OF THE REACTIVITY OF THE NITRILES RCN (R = CH3, C6H5) TOWARD THE UNSATURATED (PPH3)2(CO)HRE(MU-H)3RUH(PPH3)2 COMPLEX - REVERSIBLE HYDROGEN ELIMINATION (R = ME) OR HYDROMETALLATION REACTIONS (R = C6H5)

The complex (PPh3)2(CO)HRe(mu-H)3RuH(PPh3)2 (1) reacts with acetonitrile to give (PPh3)2(CO)Re(mu-H)3Ru(MeCN)(PPh3)2 (2). The reaction is reversible under hydrogen at atmospheric pressure. The complex 1 reacts with benzonitrile to afford (PPh3)2(CO)Re(mu-H)2(mu-NCHPh)Ru(PPh3)2(PhCN) (3), which results from a hydrometalation of the nitrile. Complex 3 has been both spectroscopically and crystallographically characterized. Crystallographic data for 3: monoclinic, P2(1)/n, a = 14.775 (2) angstrom, b = 23.775 (2) angstrom, c = 21.695 (3) angstrom, beta = 92.53 (1)-degrees, V = 7613 (2) angstrom 3, Z = 4, R = 0.049, R(w) = 0.060 for 4489 observations (F(o)2 > 3-sigma(F(o)2) and 299 variable parameters. Under CO at atmospheric pressure, the benzonitrile ligand in 3 is easily displaced to give (PPh3)2(CO)Re(mu-H)2(mu-NCHPh)Ru(CO)(PPh3)2) (4). Under 10 atm of hydrogen, 3 reverts to 1 with liberation of benzonitrile and formation of traces of benzylamine.