Zhong, WeiFei, ZhaofuScopelliti, RosarioDyson, Paul J.2016-10-182016-10-182016-10-18201610.1002/chem.201602267https://infoscience.epfl.ch/handle/20.500.14299/130335WOS:000382925000035Reaction of the pentamethylcyclopentadienyl rhodium iodide dimer [Cp*RhI2](2) with 1,1'-diphenyl-3,3'-methylenediimidazolium diiodide in non-alcohol solvents, in the presence of base, led to the formation of bis-carbene complex [Cp*Rh(bis-NHC)I] I (bis-NHC=1,1'-diphenyl-4,4'-methylenediimidazoline-5,5'-diylidene). In contrast, when employing alcohols as the solvent in the same reaction, cleavage of a methylene C-N bond is observed, affording ether-functionalized (cyclometalated) carbene ligands coordinated to the metal center and the concomitant formation of complexes with a coordinated imidazole ligand. Studies employing other 1,1'-diimidazolium salts indicate that the cyclometalation step is a prerequisite for the activation/scission of the C-N bond and, based on additional experimental data, a S(N)2 mechanism for the reaction is tentatively proposed.carbene complexesC-N bond cleavagecyclometalationimidazolium saltsN-heterocyclic carbenestext::journal::journal article::research article