Synthesis, structure, and reactivity of the ferrioarsaalkene [(eta(5)-C5Me5)(CO)(2)FeAs=C(Ph)NMe2]

Reaction of equimolar amounts of the carbenium iodide [Me2N(Ph)CSMe]I and L iAs(SiMe3)(2) . 1.5THF afforded the thermolabile arsaalkene Me3SiAs = C(Ph) NMe2 (1), which in situ was converted into the black crystalline ferrioarsa alkene [(eta (5)-C5Me)(Co)(2)FeAs=C(Ph)NMe2)] (2) by treatment with [(eta ( 5)-CSMe2)(CO)(2)FeCl]. Compound 2 was protonated by ethereal HBF4 to yield [(eta (5)-CsMe5)(Co)(2)FeAs(H)C(Ph)NMe2] BF4 (3) and methylated by CF3SO3Me to give [(eta (5)-C5Me5)(CO)(2)Fe As(Me)C(Ph)NMe2] - SO3CF3 (4). [(eta (5) -C5Me5)(Co)(2)FeAs[M(CO)(n)]C(Ph)NMe2] (5: [M(CO)(n)] = [Fe(CO)(4)]: 6: [Cr (CO)(5)]) were isolated from the reaction of 2 with [Fe-2(CO)PI or [{(Z)-cy clooctene}Cr(CO)(5)], respectively. Compounds 2-6 were characterized by mea ns of elemental analyses and spectroscopy (IR, H-1, C-13{H-1}-NMR). The mol ecular structure of 2 was determined by X-ray diffraction analysis.