COORDINATED TAUTOMERS OF A BIS-(PHOSPHORYL)-PHOSPHINE: ASSEMBLAGE OF GROUP VIB METAL COMPLEXES CONTAINING DIPHOSPHOXANE (P-O-P) LINKAGES

Article abstract of DOI:10.1016/S0022-328X(00)98615-7

Reactions of the hydrogen-bridged chealtes cis-(CO)4M(PPh2O-)2H^- (M=Cr, Mo, W) with Cl2PPh yield complexes of the type containing five-membered chelate rings.X-ray structural determination of the Mo complex confirmed the formation of the heterocycle.Crystal data: space group C2/c; a 16.477(3), b 19.845(3), c 20.512(4) Angstroem; β 106.61(2)^o; Z=8, D_calc 1.421 Mg m^-3.The final residual is 0.027 for 4737 observed reflections.The five-membered chelate ring is nonplanar with the phosphoryl P 0.888(2) Angstroem out of an approximate plane containing the other four atoms.For the tungsten analogue, 31P NMR data are consistent with the initial formation of a six-membered heterocyclic intermediate: cis-(CO)4W(PPh2-O)2PPh, which tautomerizes readily to give the final product.Six-membered chelate rings containing the (PPh2O)2PPh ligand can be assembled by the reaction of cis-(CO)4Mo(PPh2Cl)2 with (CO)5M-PPhO2H^- (M=Cr, Mo).Complexes of the type cis-(CO)4Mo(PPh2O-)2PPh-M(CO)5 (M=Cr, Mo) were isolated.Reaction of Cl2PPh with two equivalents of (CO)5Mo-PPh2O^- yields PhP(-OPPh2-Mo(CO)5)2.The above complexes represent coordination-stabilized PhP(-OPPh2)2 and tautomers of the unknown bis-(phosphoryl)-phosphine .