Anionic N-Heterocyclic Carbenes from Mesoionic Imidazolium-4-pyrrolides: The Influence of Substituents, Solvents, and Charge on their ⁷⁷Se NMR Chemical Shifts.

ABSTRACT: Mesoionic compounds are the starting material for the synthesis of unique anionic N-heterocyclic carbenes. Herein, mesoionic imidazolium pyrrolides synthesized from pyrrole-2-carbaldehyde via various N-alkyl-4-pyrroyl-imidazoles are described. These were converted into nine new 4-(pyrrol-2-yl)-substituted imidazolium salts and transformed into the mesoionic title compounds using an anion exchange resin. The DFT-calculated (B3LYP/6-311++G**) CREF values indicate a great potential for the formation of anionic N-heterocyclic carbenes by deprotonation, which were generated and reacted with selenium to obtain selenoureas. The ⁷⁷Se NMR shifts investigated under systematic variation of conditions are dependent on the substitution pattern (Δδ_Se = 133 ppm) and the steri

SUBMITTER: Pruschinski L 

PROVIDER: S-EPMC11494649 | biostudies-literature | 2024 Oct

REPOSITORIES: biostudies-literature