Nucleophilic attack on carbonyl ligands in a cyclooctatetraene (COT)-coordinated pentacarbonyl diiron complex. Isolation and transformation of the diiron bridging alkoxycarbyne complexes [Fe-2{mu-COC2H5}(COAr)(CO)(3)(eta(8)-C8H8)]

摘要

The reactions of pentacarbonyl(cyclooctatetraene)diiron, [Fe-2(CO)(5)(eta(8)-C8H8)] (1), with aryllithium reagents, ArLi (Ar = C6H5, p-CH3C6H4, p-CF3C6H4), in ether at low temperature followed by alkylation with Et3OBF4 in aqueous or CH2Cl2 solution at low temperature gave the COT-coordinated diiron bridging alkoxycarbene complexes [Fe-2{mu-C(OC2H5)Ar}(CO)(4)(eta(8)-C8H8)] (2, Ar = C6H5; 3, Ar = p-CH3C6H4; 4, Ar = p-CF3C6H4) and the novel COT-coordinated bridging alkoxycarbyne complexes [Fe-2{mu-C(OC2H5)}- (COAr)(CO)(3)(eta(8)-C8H8)] (5, Ar = C6H5; 6, Ar = p-CH3C6H4; 7, Ar = p-CF3C6H4) in 60-74% and 2-8% isolated yields, respectively. In solution complexes 5-7 were transformed into thermodynamically more stable complexes 2-4. The structure of 6 has been established by the X-ray diffraction studies.