ChemInform Abstract: Some Transition Metal Complexes of the Diacetylenic Diphosphine Ph2PC2C2PPh2: Synthesis and Crystal Structures.

Abstract

Several complexes of the acetylenic ditertiary phosphine, Ph2PC2C2PPh2, containing Mo, W, Fe, Ru or Au have been prepared; one CC triple bond in the Mo, W or Fe derivatives has been co-ordinated to Co2(CO)6 or Pt(PPh3)2 groups. Crystal structure determinations of [{Fe(CO)4}2(µ-PPh2C2C2PPh2)]3 and [Co2{µ-η2-[(OC)5W(PPh2)]CC [C2(PPh2)W(CO)5]}(CO)6]7 show that the P-bonded M(CO)n groups take up transoid positions; in 3, the PCCCCP chain, which is situated about a centre of inversion, is nearly linear [P–C–C, 173.2(5); C–C–C 179.7(6) for molecule a and 174.7(5) and 177.6(6)°, respectively, for molecule b] with CC distances of 1.192(7)A[1.201(6)A, molecule b]. In 7, co-ordination of the Co2(CO)6 group to one CC bond lengthens that bond by 0.13 A, compared with the unco-ordinated CC bond, and induces bend-back of the substituents of 141–143(1)°(PPh2) and 145–146(1)°(C2PPh2). Crystals of 3 are triclinic, space group P, a= 11.261(1), b= 12.456(2), c= 13.061(2)A, α= 79.23(2), β= 75.73(1), γ= 78.75(2)°, Z= 2; 2870 data were refined to R= 0.042, R′= 0.046. Crystals of 7 are triclinic, space group P, a= 17.940(4), b= 19.695(4), c= 16.449(2)A, α= 111.92(1), β= 108.83(1), γ= 100.29(2)°, Z= 4; 5942 data were refined to R= 0.055, R′= 0.056.