3-Diphenylphosphino-(1R)-(+)-camphor Dimethylhydrazone and its Complexes with Group 6 Metal Carbonyls: Crystal Structures of the Hydrazone and

Article abstract of DOI:10.1039/DT9910001183

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 quarternized with MeI to give a phosphonium salt and converted into the corresponding sulphide and oxide.Treatment of (M=Cr, Mo or W; nbd=norbornadiene) with 3c gives 4 in which the phosphine is chelated to the metal in a six membered ring.However, when was heated with 3c in decane, isomerization around the C=N bond occured and the isomeric complex 5 was formed.When 4a was heated in diglyme it isomerized to 5.Proton and 31P-<1H> NMR and infrared data are given.Crystals of compound 3c are orthorhombic, space group P2₁2₁2₁ 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 P2₁2₁2₁, 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 unco-ordinated NMe2 group.The arrangement around the C=N is E, i.e. the opposite to that in 3c.

Full text of DOI:10.1039/DT9910001183

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