Reactivity of [Re 2(CO) 8(MeCN) 2] with thiazoles: Hydrido bridged dirhenium compounds bearing thiazoles in different coordination modes

Abstract

Reactions of the labile compound [Re 2(CO) 8(MeCN) 2] with thiazole and 4-methylthiazole in refluxing benzene afforded the new compounds [Re 2(CO) 7{μ-2,3-η 2-C 3H(R)NS}{η 1-NC 3H 2(4-R)S}(μ-H)] ( 1, R = H; 2, R = CH 3), [Re 2(CO) 6{μ-2,3-η 2-C 3H(R)NS}{η 1-NC 3H 2(4-R)S} 2(μ-H)] ( 3, R = H; 4, R = CH 3) and fac-[Re(CO) 3(Cl){η 1-NC 3H 2(4-R)S} 2] ( 5, R = H; 6, R = CH 3). Compounds 1 and 2 contain two rhenium atoms, one bridging thiazolide ligand, coordinated through the C(2) and N atoms and a η 1-thiazole ligand coordinated through the nitrogen atom to the same Re as the thiazolide nitrogen. Compounds 3 and 4 contain a Re 2(CO) 6 group with one bridging thiazolide ligand coordinated through the C(2) and N atoms and two N-coordinated η 1-thiazole ligands, each coordinated to one Re atom. A hydride ligand, formed by oxidative-addition of C(2)–H bond of the ligand, bridges Re–Re bond opposite the thiazolide ligand in compounds 1– 4. Compound 5 contains a single rhenium atom with three carbonyl ligands, two N-coordinated η 1-thiazole ligands and a terminal Cl ligand. Treatment of both 1 and 2 with 5 equiv. of thiazole and 4-methylthiazole in the presence of Me 3NO in refluxing benzene afforded 3 and 4, respectively. Further activation of the coordinated η 1-thiazole ligands in 1– 4 is, however, unsuccessful and results only nonspecific decomposition. The single-crystal XRD structures of 1– 5 are reported.