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• 91222-65-0 3,3-dimethyl-1-(diphenylphosphino)butan-2-one 

Relevant academic research and scientific papers

Synthesis and characterisation of oxo- and phenylimido-rhenium(v) complexes containing bidentate phosphinoenolato ligands

Reacting 1-phenyl-2-(diphenylphosphino)ethanone (P1～OH), 1-tert-butyl-2-(diphenylphosphino)ethanone (P2～OH) and 1-phenyl-2-(diphenylphosphino)propanone (P3～OH) with ReOCl3(PPh3)2 and Re(NPh)Cl3-(PPh3)2 in toluene and ethanol in the presence of NEt3 yields complexes in which these ligands bind as monoanionic enolato chelating agents. Bromo and iodo analogues are prepared similarly. The reactions are solvent dependent. The disubstituted ReOCl(P～O)2 compounds obtained in toluene adopt the 'twisted' cis-(P,P) octahedral structure. With Re(NPh)Cl3-(PPh3)2, P1～OH and P2～OH give the corresponding Re(NPh)Cl(P～O)2 compounds and the trans-(P,P)-trans-(Cl, Cl) isomer of monosubstituted Re(NPh)Cl2(PPh3)(P～O) as the major products, together with small amounts of 'twisted' trans-(P,P) Re(NPh)Cl(P～O)2. The monosubstituted complex is the only species isolated with P3～OH. The major structural difference between the two systems is the small stability gap between the cis- and the trans-(P,P) isomers of the imido complexes. In ethanol, unexpected cis-ethoxo-oxo complexes ReO(OEt)(P～O)2 are isolated, resulting from stereoselective substitution of the halide in the 'twisted' cis-(P,P) octahedral complexes. The reactions with Re(NPh)Cl3(PPh3)2 are less selective and give rise to mixtures of complexes. The trans-ethoxo-phenylimido compound Re(NPh)(OEt)(P1～O)2 is obtained in good yield. A crystallographic study reveals an unexpected 'equatorial' trans-(P,P) structure with the ethoxo ligand trans to the Re=NPh bond. 1H NMR indicates that the ethoxo ligand acts as an electron reservoir in these complexes, since its protons are strongly deshielded in the cis-oxo-ethoxo species and strongly shielded in the trans-phenylimido-ethoxo complex.