Dirhenium carbonyl complexes bearing 2-vinylpyridine, morpholine and 1-methylimidazole ligands

Abstract

Treatment of the labile compound [Re 2(CO) 8(MeCN) 2] with 2-vinylpyridine in refluxing benzene affords exclusively the new compound [Re 2(CO) 8(μ-η 1:η 2-NC 5H 4CH CH 2)] ( 1) in 39% yield in which the μ-η 1:η 2-vinylpyridine ligand is coordinated to one Re atom through the nitrogen and to the other Re atom via the olefinic double bond. Reaction of [Re 2(CO) 8(MeCN) 2] with morpholine in refluxing benzene furnishes two compounds, [Re 2(CO) 9(η 1-NC 4H 9O)] ( 2) and [Re 2(CO) 8(η 1-NC 4H 9O) 2] ( 3) in 5% and 29% yields, respectively. Reaction of [Re 2(CO) 8(MeCN) 2] with 1-methylimidazole gives [Re 2(CO) 8{η 1-NC 3H 3N(CH 3)} 2] ( 4) and the mononuclear compound fac-[ReCl(CO) 3{η 1-NC 3H 3N(CH 3)} 2] ( 5) in 18% and 26% yields, respectively. In the disubstituted compounds 2 and 4, the heterocyclic ligands occupy equatorial coordination sites. The mononuclear compound 5 consists of three CO groups, two N coordinated η 1-1-methylimidazole ligands and a terminal Cl ligand. The XRD structures of complexes 1, 3 and 5 are reported.