Studies on the Effect of Positive and Negative Charges on the ⁷⁷Se NMR Shifts of Selenones and Selenenyls of N-heterocyclic Carbenes of Imidazolium-4,5-dicarboxylates.

ABSTRACT: 1,3-Imidazole-4,5-dicarboxylic acid derivatives were investigated with respect to the properties of the underlying N-heterocyclic carbenes. Their selenium adducts were prepared as diesters, monoesters, and dianionic dicarboxylates. Se-methylation yielded selenenyls (cationic selenoethers). ⁷⁷Se NMR shifts of selenium adducts are considered a measure of the electronic properties of the underlying N-heterocyclic carbene. Since they are very sensitive to external (solvent, pH, temperature, reference reagent, reference method) and internal parameters (substituent effects, steric effects, nonclassical H-bonding, anisotropy), difficulties can arise in reliably interpreting these values. Our model compounds allow the systematic investigation of the influence of charges on the ^77</

SUBMITTER: Pruschinski L 

PROVIDER: S-EPMC11833865 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature