DNP NMR spectroscopy enabled direct characterization of polystyrene-supported catalyst species for synthesis of glycidyl esters by transesterification

Abstract

Polymer-supported catalysts have been of great interest in organic syntheses, but have suffered from the difficulty to obtain direct structural information regarding the catalyt species embedded in the polymer due...

Experimentally Established 15N NMR Absolute Shielding Scale for Theoretical Calculations

“…Nitrogen centers of many organic and inorganic molecules are active or potentially active for various non-covalent − and coordinative interactions. , The low natural abundance and the gyromagnetic ratio of the 15 N isotope make its detection difficult. However, this problem can be solved either by isotopic labeling , or by specially designed NMR methods. − In this work, the experimentally measured 15 N NMR chemical shift tensors (CSTs) will be compared with the calculated nitrogen absolute shielding tensors in order to identify the molecules for which these tensors are close up to a constant. This constant is σ ref ( 15 N).…”

Supercritical CO2 impregnation process applied to polymer samples preparation for dynamic nuclear polarization solid‐state NMR

“…In other words, investigators should try and adapt the various available protocols to their specific case, and this may prove daunting. This is especially true for polymer materials where careful optimization of sample preparation conditions is typically required to achieve meaningful results, [29][30][31][32][33][34][35][36] with no guarantee of success in the end. In parallel, supercritical CO 2 (scCO 2 ) impregnation has been used for a long time in the field of polymer materials to impregnate specific components (e.g., additives, active pharmaceutical ingredients, dyes, and organic metallic complexes) in a polymer matrix.…”

Rapid alcoholysis of cyclic esters using metal alkoxides: access to linear lactyllactate-grafted polyglycidol

“…Recent excellent work by Tanaka et al, revealed that glycidyl esters could be synthesized from glycidol and methyl esters via transesterification. 22,23 Other recent work by Ishihara et al, also disclosed the synthesis of glycidyl (meth)acrylate from a transesterification of methyl (meth)acrylate with glycidol. 24 However, there is no report on the alcoholysis of cyclic esters such as lactide and lactones by glycidol in the literature although copolymerization of glycidol and lactide were reported.…”