The reactivity of alkynes with the imido clusters Ru3(μ3-NPh)2(CO)9, H2Ru3(μ3-NPh)(CO)9, Fe3(μ3-NPh)(CO)10, Fe3(μ3-NPh)2(CO)9, and H2Fe3(μ3-NPh)(CO)9has been examined. The cluster Fe2(μ3-NPh)(CO)10reacts regiospecifically with a series of alkynes to form the binuclear ferrapyrrolinone complexes Fe2(μ2-η3-RC=C(R’)C(O)NPh)(CO)6, possessing a metallacycle formed by coupling of the alkyne with CO and the imido ligand. These same ferrapyrrolinone complexes also form when H2Fe3(μ3-NPh)(CO)9is allowed to react with PhC≡CPh, EtC≡CEt, and PhC≡CMe. The derivative formed from PhC≡CMe was found to undergo subsequent substitution of one CO ligand by But≡C to form Fe2(μ2-η3-PhC=C(Me)C(O)-NPh)(CO)5(CNBut), which was crystallographically characterized. The bis(imido) cluster Ru3(μ3-NPh)2(CO)9reacts with PhC≡CPh to form the tetranuclear cluster Ru4(μ3-NPh)2(η2-μ2-PhC≡CPh)(CO)10, which has been crystallographically shown to possess a butterfly arrangement of the four ruthenium atoms with the alkyne bridging the hinge of the butterfly in a perpendicular fashion and with the imido ligands bridging the open triangular faces of the butterfly. The analogous triiron cluster Fe3(μ3-NPh)2(CO)9reacts with PhC≡CPh to give a mixture of products, from which the ferracyclopentadiene Fe2(μ2-η4-PhC=C(Ph)C-(Ph)=CPh)(CO)6and the binuclear ferraazetine complex Fe2(μ2-η3-PhC=C(Ph)NPh)(CO)6were characterized. The latter compound possesses a four-membered metallacycle formed by coupling of the alkyne with the imido ligand. Treatment of H2Ru3(μ3-NPh)(CO)9with PhC≡CPh results in the formation of the cluster Ru4(μ4-NPh)(μ4-η2-PhC≡CPh)(CO)11, which has been crystallographically shown to possess a planar arrangement of the four ruthenium atoms bridged on one side by the μ4-imido ligand and the other by the alkyne. The cluster Fe3(μ3-NPh)(CO)10has also been found to react with 1,3-cyclohexadiene and with aliene to respectively form the trinuclear clusters Fe3(μ3-NPh)(CO)8(η4-1,3-cyclohexadiene) and Fe3(μ3-NPh)(CO)8(μ2-η6-C6H8). Crystallographic characterization has shown that in the former the diene has replaced two CO's and is coordinated to a single iron atom whereas in the latter two alienes have coupled through their central carbon atoms to form a C6H8ligand that bridges two iron atoms with each C3H4unit of the ligand η3-bonded to a single iron.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry