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• 84661-56-3 1,1'-bis(imidazolyl)methane 
• 100-44-7 benzyl chloride 
• 4238-71-5 1-benzylimidazole 
• 75-09-2 dichloromethane 

Relevant academic research and scientific papers

Stirring or milling? First synthesis of Rh(I)-(di-N-heterocyclic carbene) complexes both in solution and in a ball mill

An environment-friendly, convenient, fast and solvent-free mechanochemical approach have been accomplished for the synthesis of several diimidazolium salts and the bridging dinuclear rhodium(I)–N-heterocyclic carbene complexes of the type [{RhCl(cod)}2(μ-di-NHC)] derived from them. The compounds were synthesized also by the classical solvent method and the results of the two approaches were compared. A systematic study of both the mechanochemical and the solvent syntheses has also been carried out to determine the effects of various factors influencing the reactions. This is the first report on the mechanochemical synthesis of poly-NHC metal complexes as well as NHC–Rh complexes in ball mill. Comparative synthesis of several new, structurally well characterized alkylene-bridged diimidazolium salts and the respective dinuclear Rh(I)-(di-N-heterocyclic carbene) complexes, [{RhCl(cod)}2(μ-di-NHC)], both by mechanochemical and traditional solvent methods, revealed advantages of the mechanochemical (ball-mill) synthesis, such as reduced solvent need, shorter reaction times and competitive or higher product yields.

Expedient Synthesis of Bis(imidazolium) Dichloride Salts and Bis(NHC) Complexes from Imidazoles Using DMSO as a Key Polar Additive

A general approach for the synthesis of bis(imidazolium) dichloride salts from imidazoles and dichloroalkanes is reported. Typical limitations of this reaction for the formation of methylene-bridged derivatives are addressed herein through the use of excess CH2Cl2 in the presence of DMSO as a polar cosolvent, significantly improving the conversion rates presumably via stabilization of the initial SN2 transition state. The method was also shown to be applicable to the formation of bis(pyridinium) dichloride salts from pyridine derivatives, and to the direct synthesis of metal-bis(NHC) complexes from imidazoles.

Ruthenium catalysts for hydrogenation of aromatic and aliphatic esters: Make use of bidentate carbene ligands

Committed carbenes: The convenient application of bidentate carbene ligands is described for the hydrogenation of carboxylic acid esters. The ligand precursors are easily synthesized through the dimerization of N-substituted imidazoles with diiodomethane. The catalyst is generated in situ and exhibits good activity and functional group tolerance for the hydrogenation of aromatic and aliphatic carboxylic acid esters. Copyright

Synthesis and characterization of Di- and tetracarbene iron(II) complexes with chelating N-heterocyclic carbene ligands and their application in aryl Grignard-Alkyl halide cross-coupling

A series of new and known bis(imidazolium) chloride and bromide salts bridged by either a methylene group (1-8, 10a,b) or an ethylene group (9a,b) and bearing different N substituents (Me, Et, Bn, tBu, Mes) have been reacted with [Fe{N(SiMe3)2}2]2 to yield the four-coordinate iron(II) complexes [LFeX2] (11-20; X = Cl, Br; L = chelating bis(imidazolylidene) ligand). Molecular structures of six of these complexes have been characterized by X-ray crystallography, and selected examples have been characterized by 1H NMR and UV-vis spectroscopy, cyclic voltammetry, Moessbauer spectroscopy, and SQUID magnetometry. In all cases the iron(II) is found in a distorted-tetrahedral environment; it is in the high-spin state and shows large quadrupole splittings in the range 3.67-4.03 mm?s-1 (δ = 0.73-0.81 mm?s-1). Subtleties of the metric parameters depend on the bridging unit between the two imidazolylidene groups, the peripheral N substituents, and the coligand (Cl or Br). In case of rather small (Me, Et) or flexible (Bn) N substituents the dicarbene species [LFeX2] are formed together with ferrous tetracarbene complexes [L2FeX2] (21-23), which are difficult to separate and could not be isolated in pure form. When the latter are dissolved in MeCN in the presence of residual [FeBr2(solv) x], however, they transform into the ionic complexes [L 2Fe(MeCN)2][FeBr4] (24-26), which have been characterized by single-crystal X-ray diffraction. They feature low-spin iron(II) (Moessbauer parameters δ ≈ 0.15 mm s-1, ΔEQ ≈ 1.36 mm s-1) and distorted-octahedral structures with the two MeCN ligands in a cis configuration. Selected examples of the new dicarbene complexes [LFeX2] have been tested as catalysts for the standard cross-coupling reaction between p-tolylmagnesium bromide and bromo- or chlorocyclohexane. They show moderate activity that appears to be generally lower than for related complexes with two monodentate NHC ligands, but the activities clearly depend on the peripheral N substituents and the linker between the two imidazolylidene groups; the best results are obtained for complex 19, which features a long ethylene bridge and bulky Mes substituents, and hence the most shielded metal center.

N-Polyazolylmethanes. III. Synthese et etude rmn du proton des derives du methylene-1,1' diimidazole et du methylene-1,1' dibenzimidazole

Several quaternary salts derived from 1,1'-methylenediimidazole and 1,1'-methylenedibenzimidazole have been prepared.A comparative study with the salts derived from 1-methylimidazole and 1-methylbenzimidazole has been carried out using proton magnetic resonance.Nuclear Overhauser effect and shift reagents have been used for the assignment of heterocyclic protons.