Formation of Ferriophosphanyl- and Ferrioarsanyl-Functionalized Carbocation Salts by Alkylation, Protonation and Silylation of (η5-C5Me5)(CO)2FePn=C(NMe2)2 (Pn = P, As)

Weber L, Scheffer MH, Stammler H-G, et al. Formation of Ferriophosphanyl- and Ferrioarsanyl-Functionalized Carbocation Salts by Alkylation, Protonation and Silylation of (η5-C5Me5)(CO)2FePn=C(NMe2)2 (Pn = P, As). Organometallics. 1999;18(20):4216-4221.Reaction of equimolar amounts of the metallophosphaalkene eta(5)-Cp*(CO)(2)FeP=C(NMe2)(2) (1a) and the metalloarsaalkene eta(5)-Cp*(CO)(2)FeAs=C(NMe2)(2) (1b) with ethereal HBF4 or the trifluoromethanesulfonates ROSO2CF3 (R = CH3, Me3SiCH2, Me3Si), respectively, afforded the phosphanyl-substituted carbenium salts [eta(5)-Cp*(CO)(2)FeP(R)C(NMe2)(2)]X (2a, R = H, X = BF4; 3a, R = CH3, X = SO3CF3; 4a, R = Me3SiCH2, X = SO3CF3; 5a, R = Me3Si, X = SO3CF3) as well as their arsenic analogues [eta(5)-Cp*(CO)(2)FeAs(R)C(NMe2)(2)]X (2b, R = H, X = BF4; 3b, R = CH3, X = SO3CF3; 4b, R = Me3SiCH2, X = SO3CF3; 5b, Me3Si, X = SO3CF3). The cations feature a trigonal-planar bis(amino)carbenium center, which is connected to a phosphorus or arsenic atom with pyramidal configuration. The molecular structure of 3b has been determined by X-ray diffraction analysis