1372124-93-0

Usage

Reactions

1,3-bis(mesityl)imidazolium hydrogen carbonate is used as a source of NHC’s and can be transferred to transition metals. This catalyst is used in the benzoin condensation reaction.

Upstream product

• 298-14-6 potassium hydrogencarbonate 
• 141556-45-8 1,3-bis(mesityl)imidazolium chloride 

Downstream Products

• 917604-43-4 1,3-bis(2,4,6-trimethylphenyl)imidazolium-2-dithiocarboxylate 
• 108-32-7 1,2-propylene cyclic carbonate 

Relevant academic research and scientific papers

Imidazol(in)ium hydrogen carbonates as a genuine source of N-heterocyclic carbenes (NHCs): Applications to the facile preparation of NHC metal complexes and to NHC-organocatalyzed molecular and macromolecular syntheses

Anion metathesis of imidazol(in)ium chlorides with KHCO3 afforded an easy one step access to air stable imidazol(in)ium hydrogen carbonates, denoted as [NHC(H)][HCO3]. In solution, these compounds were found to be in equilibrium with

Imidazolium hydrogen carbonates versus imidazolium carboxylates as organic precatalysts for N-heterocyclic carbene catalyzed reactions

Imidazolium-2-carboxylates (NHC-CO2 adducts, 3) and (benz)imidazolium hydrogen carbonates ([NHC(H)][HCO3], 4) were independently employed as organic precatalysts for various molecular N-heterocyclic carbene (NHC) catalyzed reactions. NHC-CO2 adducts were obtained by carboxylation in THF of related free NHCs (2), while the synthesis of [NHC(H)][HCO3] precursors was directly achieved by anion metathesis of imidazolium halides (1) using potassium hydrogen carbonate (KHCO3) in methanolic solution, without the need for the prior preparation of free carbenes. Thermogravimetric analysis (TGA) and TGA coupled with mass spectrometry (TGA-MS) of most [NHC(H)][HCO3] precursors 4 showed a degradation profile in stages, with either a concomitant or a stepwise release of H2O and CO2, between 108 and 280 °C, depending on the nature of the azolium and substituents. In solution, NHC generation from both [NHC(H)][HCO3] salts and NHC-CO2 adducts could be achieved at room temperature, most likely by a simple solvation effect. Both types of precursors proved efficient for organocatalyzed molecular reactions, including cyanosilylation, benzoin condensation, and transesterification reactions. The catalytic efficiencies of NHC-CO2 adducts 3 were found to be approximately 3 times higher than those of their [NHC(H)][HCO3] counterparts 4.