3-DIPHENYLPHOSPHINO-(1R)-(+)-CAMPHOR DIMETHYLHYDRAZONE AND ITS COMPLEXES WITH GROUP-6 METAL-CARBONYLS - CRYSTAL-STRUCTURES OF THE HYDRAZONE AND [MO(CO)4(PPH2C10H15NNME2)]

Prolonged treatment of (1R)-(+)-camphor with 1,1-dimethylhydrazine gives (1R)-(+)-camphor dimethylhydrazone 3a which with LiBu, followed by PPh2Cl, gives the corresponding compound 3c which has the Ph2P group in 3-exo position and the C = N-NMe2 group in the Z configuration. This new phosphine was quaternized with Mel to give a phosphonium salt and converted into the corresponding sulphide and oxide. Treatment of [M(CO)4(nbd)] (M = Cr, Mo or W; nbd = norbornadiene) with 3c gives [activated M(CO)4(PPh2C10H15NNMe2)] 4 in which the phosphine is chelated to the metal in a six-membered ring. However, when [Mo(CO)6] was heated with 3c in decane, isomerization around the C = N bond occurred and the isomeric complex [activated Mo(CO)4(PPh2C10H15NNMe2)] 5 was formed. When 4a was heated in diglyme it isomerized to 5. Proton and P-31-{H-1} NMR and infrared data are given. Crystals of compound 3c are orthorhombic, space group P2(1)2(1)2(1) with a = 1119.9(2), b = 1166.3(2), c = 1690.7(2) pm and Z = 4; final R factor 0.0443 for 3910 observed reflections. Crystals of complex 5 are orthorhombic, space group P2(1)2(1)2(1), with a = 974.8(2), b = 1658.9(4), c = 1982.0(4) pm and Z = 4; R 0.0425 for 2991 observed reflections. The structure shows that the co-ordinated PPh2 group is in the 3-exo position whilst the C = NNMe2 moiety is co-ordinated through the C = N nitrogen, giving a five-membered co-ordinated ring and an uncoordinated NMe2 group. The arrangement around the C = N is E, i.e. the opposite to that in 3c.