摘要:
The incorporation of a phosphinimino moiety into phosphine ligands to form a new bidentate Ph(3)P=N(CH2)(3)PPh(2) (1) is reported. Compound 1 can act as a sigma-N and sigma-P donor ligand or react with metal carbonyls to form isocyanide complexes. Complexes of (CO)(4)M-(1-P,N) [M = Mo (2), W (3)] were prepared from the reaction of ET(4)N[M(CO)(5)Br] with 1 in refluxing THF solution, whereas the isocyanide complexes of (CO)(5)MCN(CH2)(3)PPh(2) [M = Cr (4), Mo (5), W (6)] are obtained from the reaction of M(CO)(6) with 1 at 25 degrees C. The deoxygenation nature is also shown in the reaction of CpFe(CO)(2)I, CpRu(CO)(2)I, Re(CO)(5)Br, and Re-2(CO)(10) with 1 to form the corresponding isocyanide complexes [CpFe(CO){CN(CH2)(3)-PPh(2)-C,P}]I (7), CpRu(CO)I{CN(CH2)(3)PPh(2)-C} (10), BrRe(CO)(5-n){CN(CH2)(3)PPh(2)-C}(n) {n = 1(12), 2 (14)], and Re-2(CO)(9){CN(CH2)(3)PPh(2)-C} (15), respectively. The free phosphine of 10 underwent exchange with one triphenylphosphine ligand in CpRu(PPh(3))(2)Cl to yield the binuclear species [CpRu(PPh(3))Cl{P(Ph(2))(CH2)(3)NC}Ru(CO)CpI] (11), whereas intramolecular ligand substitution occurred in both 12 and 15 to give Br(CO)(3)Re{CN(CH2)(3)PPh(2)-C,P} (13) and {mu-CN(CH2)(3)PPh(2)}Re-2(CO)(8) (16). Reaction of (COD)PdCl2 with 1 produced the complex (1-P,N)PdCl2 (18), in which 1 acts as a sigma-N, sigma-P bidentate ligand. X-ray crystal structural analysis of [CpFe(CO){CN(CH2)(3)PPh(2)-C,P}]PF6 (7a) and 18 confirmed the formulation of both complexes. The C=N bond distance [1.20(3) Angstrom] of 7a is greater than those in the related iron-isocyanide complexes; the angle C-N-C [141(2)degrees] deviates from 180 degrees, indicating that the resonance contribution of Fe=C=N- is more important than that of Fe-C=N-. These observations are consistent with spectral data, the smaller infrared stretching wavenumber (2089 cm(-1)), and the greater shift (C-13 NMR delta 183.7 ppm) of the isocyanide moiety of 7.