Reactivity of [Re2(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 {l-2,3-g 2 -C 3 H(R)NS}{g 1 -NC 3 H 2 (4-R)S}(l-H)] (1, R = H; 2, R = CH 3 ), [Re 2 (CO) 6 {l-2,3-g 2 -C 3 H(R)NS}{g 1 -NC 3 H 2 (4-R)S} 2 (l-H)] (3, R = H; 4, R = CH 3 ) and fac-[Re(CO) 3 (Cl){g 1 -NC 3 H 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 g 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 g 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 g 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 3 NO in refluxing benzene afforded 3 and 4, respectively. Further activation of the coordinated g 1 -thiazole ligands in 1-4 is, however, unsuccessful and results only nonspecific decomposition. The single-crystal XRD structures of 1-5 are reported.

Reactions of rhenium and manganese carbonyl complexes with 1,8-bis(diphenylphosphino)naphthalene: Ligand chelation, C–H and C–P bond-cleavage reactions

“…The infrared spectrum display three bands in the carbonyl stretching region indicating the fac arrangement of the carbonyls, similar to those observed for fac-[Re(CO) 3 L 2 X] type compounds [24][25][26][27][28]. In addition to the usual phenyl and naphthyl Re 2 (CO) 8 proton resonances in the aromatic region d 7.92-6.50, the 1 H NMR spectrum shows a doublet of doublets at d 4.93 (integrating to 1H) assigned to the PH proton of the diphenylphosphine ligand.…”

“…The coordination geometry of the Re atom can be described as a distorted octahedron with three carbonyl ligands arranged in a facial fashion. The distortion from octahedral coordination geometry is evident from reduction of the P-Re-P angle from 90°in the idealized polyhedron to 82.50 (11) [25]. The reason for lengthening the other two Re-CO bond distances is probably due the trans effect of the two P atoms of the chelating dppn ligand.…”

“…The fivemembered chelate metallocycle ring is nearly coplanar and the orientation of the phenyl rings is unusual and presumably would not persist in solution. The carbonyl groups assume a fac geometry with a longer average Re-CO bond distance of 1.950 (9) (7) Å} [24,25].…”

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

“…To gain insight into the reactivity of secondary aliphatic heterocyclic amines toward rhenium carbonyl complexes, we have investigated the reaction of morpholine with [Re 2 (CO) 8 (MeCN) 2 ] to isolating the g 1 -coordinated compound [Re 2 (CO) 8 . Both compounds 2 and 3 have been characterized by elemental analysis, IR, 1 H NMR and mass spectral data together with single crystal X-ray diffraction analysis for 3.…”

“…The synthesis and reactivity of the dirheniumpyridyl compound [Re 2 (CO) 8 (l-g 2 -C 5 H 4 N)-(l-H)] were investigated by Brown and co-workers in 1982 [7]. Arce et al [4] reported the bipyridyldirhenium complexes [Re 2 (CO) 8 (l-g 3 -C 12 H 10 N 2 )], [Re 2 (CO) 7 (l-g 3 -C 12 H 9 N 2 )-(l-H)], [Re 2 (CO) 6 (l-g 4 -C 12 H 9 N 2 )(l-H)], [Re 2 (CO) 8 (l-g 4 -C 12 H 10 N 2 )] and [Re 2 (CO) 6 (l-g 6 -C 24 8 (MeCN) 2 ] with thiazole and 4-methylthiazole [8].…”