The reactivity of alcohols can be enhanced by the temporary removal of hydrogen using a transition metal catalyst to generate an intermediate aldehyde or ketone. The so-formed carbonyl compound has a greater reactivity towards nucleophilic addition accommodating the in situ formation of imines or alkenes. The return of hydrogen from the catalyst leads to the formation of new C-N and C-C bonds, often with water as the only reaction by-product.
A selective catalytic meta sulfonation of 2-phenylpyridines was found to occur in the presence of (arene)ruthenium(II) complexes upon reaction with sulfonyl chlorides. The 2-pyridyl group facilitates the formation of a stable Ru-C(aryl) σ bond that induces a strong para-directing effect. Electrophilic aromatic substitution proceeds with the sulfonyl chloride to furnish a sulfone at the position meta to the chelating group. This new catalytic process offers access to atypical regioselectivity for reactions involving chelation-assisted cyclometalation.
The two-coordinate cationic Ni(I) bis-N-heterocyclic carbene complex [Ni(6-Mes)2]Br (1) [6-Mes =1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene] has been structurally characterized and displays a highly linear geometry with a C-Ni-C angle of 179.27(13)°. Density functional theory calculations revealed that the five occupied metal-based orbitals are split in an approximate 2:1:2 pattern. Significant magnetic anisotropy results from this orbital degeneracy, leading to single-ion magnet (SIM) behavior.
Thermolysis of Ru(PPh3)3(CO)H2 with the N-heterocyclic carbene bis(1,3-(2,4,6-trimethylphenyl)imidazol-2-ylidene) (IMes) results in C-C activation of an Ar-CH3 bond in one of the mesityl rings of the carbene ligand. Upon addition of IMes to Ru(PPh3)3(CO)H2 at room temperature in the presence of an alkene, C-H bond activation is observed instead. The thermodynamics of these C-C and C-H cleavage reactions have been probed using density functional theory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.