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 (l-g 1 :g 2 -NC 5 H 4 CH@CH 2 )] (1) in 39% yield in which the l-g 1 :g 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 (g 1 -NC 4 H 9 O)] (2) and [Re 2 (CO) 8 (g 1 -NC 4 H 9 O) 2 ] (3) in 5% and 29% yields, respectively. Reaction of [Re 2 (CO) 8 (MeCN) 2 ] with 1-methylimidazole gives [Re 2 (CO) 8 {g 1 -NC 3 H 3 N(CH 3 )} 2 ] (4) and the mononuclear compound fac-[ReCl(CO) 3 {g 1 -NC 3 H 3 N(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 g 1 -1-methylimidazole ligands and a terminal Cl ligand. The XRD structures of complexes 1, 3 and 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 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].…”

New molecular architectures containing low-valent cluster centres with di- and trimetalated 2-vinylpyrazine ligands: synthesis and molecular structures of Ru5(CO)15(μ5-C4H2N2CHCH)(μ-H)2 and Ru8(CO)24(μ7-C4H2N2CHC)(μ-H)3

“…The structure of 2 consists of individual Ru 3 and Ru 2 units linked via a dimetalated m 5 -C 4 H 2 N 2 CH]CH ligand formed upon the expected activation of a b-C-H alkenyl bond, and metalation of the ring proton directly trans to the vinyl group. The Ru 2 unit is coordinated by one of the ring nitrogen atoms and the metalated vinyl moiety of the heterocyclic ligand in such a way that one ruthenium is bonded to the ring nitrogen and the b-carbon of the vinyl moiety, while the other ruthenium makes a s,p-vinyl type interaction with the vinylic double bond and ipso carbon, C (18). The heterocyclic ligand is coordinated to the Ru 3 unit by capping one face of the ruthenium triangle using the second ring nitrogen atom and an adjacent ring carbon; thus importantly, two of the ring carbon atoms are now sp 3 -hybridized.…”

“…Thus, the metalated derivatives of 2-vinylpyridine have been shown to bind up to four metal atoms, acting as 4-6 electron donors (A-E, Chart 1). [13][14][15][16][17][18][19] The chemistry of the closely related 2-vinylpyrazine, which contains an additional nitrogen atom within the heterocyclic ring, has been far less studied. [20][21][22] Usually, reactions of these ligands with unsaturated appendages proceed through C-H activation of the vinyl group with concomitant coordination of the adjacent ring nitrogen.…”

Synthesis, spectral characterization, DFT studies and biological activity of novel Ligand 1‐(2‐cyclohexyl thioethyl) piperidine and its complexes with group 12 metal chlorides

“…Antioxidant and hypocholesterolemic activities of 2‐biphenylmorpholine derivatives have also been reported. The complexes of morpholine and its derivatives with Ni (II), Cu (II), Zn (II), Cd (II), Hg (II), Os (II), Re (III) and Ag (I) have been reported. Platinum (II)‐N‐(2‐aminoethyl)morpholine complexes have exhibited antitumor activities .…”