Novel dimetal bridging carbene complexes derived from a terminal carbonyl dimetal compound. Syntheses, structures and reactivities of 7H-indene-coordinated diiron bridging carbene complexes

摘要

Pentacarbonyl-7H-indenediiron, [Fe-2(CO)(5)(eta(3),eta(5)-C9H8)] ( 1), reacts with aryllithium, ArLi (Ar = C6H5, p-C6H5C6H4), followed by alkylation with Et3OBF4 to give novel 7H-indene-coordinated diiron bridging alkoxycarbene complexes [Fe-2{mu-C(OC2H5) Ar}(CO)(4)(eta(4),eta(4)-C9H8)] ( 2, Ar = C6H5; 3, Ar = p-C6H5C6H4). Complexes 2 and 3 react with HBF4 center dot Et2O at low temperature to yield cationic bridging carbyne complexes [Fe-2(mu-CAr)(CO)(4)(eta(4),eta(4)-C9H8)] BF4 ( 4, Ar = C6H5; 5, Ar = p-C6H5C6H4). Cationic 4 and 5 react with NaBH4 in THF at low temperature to afford diiron bridging arylcarbene complexes [Fe-2{mu-C(H) Ar}(CO)(4)(eta(4),eta(4)-C9H8)] (6, Ar = C6H5; 7, Ar = p-C6H5C6H4). The similar reactions of 4 and 5 with NaSC6H4CH3-p produce the bridging arylthiocarbene complexes [Fe-2{mu-C(Ar) SC6H4CH3-p}( CO)(4)(eta(4),eta(4)-C9H8)] (8, Ar = C6H5; 9, Ar = p-C6H5C6H4). Cationic 4 and 5 can also react with anionic carbonylmetal compounds Na[M(CO)(5)(CN)] (M = Cr, Mo, W) to give the diiron bridging aryl(pentacarbonylcyanometal) carbene complexes [Fe-2{mu-C(Ar) NCM(CO)(5)}(CO)(4)(eta(4),eta(4)-C9H8)] ( 10, Ar = C6H5, M = Cr; 11, Ar = p-C6H5C6H4, M = Cr; 12, Ar = C6H5, M = Mo; 13, Ar = p-C6H5C6H4, M = Mo; 14, Ar = C6H5, M = W; 15, Ar = p-C6H5C6H4, M = W). Interestingly, in CH2Cl2 solution at room temperature complexes 10 - 15 were transformed into the isomerized 7H-indene-coordinated monoiron complexes [Fe(CO)(2)(eta(5)-C9H8)C(Ar) NCM(CO)(5)] (16, Ar = C6H5, M = Cr; 17, Ar = p-C6H5C6H4, M = Cr; 18, Ar = C6H5, M = Mo; 19, Ar = p-C6H5C6H4, M = Mo; 20, Ar = C6H5, M = W; 21, Ar = p-C6H5C6H4, M = W), while complex 3 was converted into a novel ring addition product [Fe-2{C(OC2H5)C6H4C6H5-p-(eta(2),eta(5)-C9H8)}(CO)(5)] ( 22) under the same conditions. The structures of complexes 2, 6, 8, 14, 18 and 22 have been established by X-ray diffraction studies.