²³Na‐NMR. Linewidths in Binary Mixtures of Oxygenated Solvents

Abstract

Summary. The inference of single bicyclic intermediates in t h e competition of diglymc (or triglyme) 1) with tetrahydrofurfuryl alcohol is confirmed by analysis of the linewidths. The dissymetric bicyclic species are characterized by linewidths increased markcdly with respect to the pure solvents, without an acisompanying change in the 23Na chemical shift. Conversely, the competition of glyme with the same alcohol involves three equi-probable intermediates; that of tetrahydrofuran (or tetrahydropyran) is of greatcr conceptual complexity.

Preparation and Characterization of Sodium Poly(α,l-glutamate)/Poly(ethylene oxide) Macromolecular Complexes

“…Solution NMR spectra were acquired on a Bruker ARX 400 spectrometer at room temperature using D 2 O and CDCl 3 as solvents. TMS was used as the external standard for obtaining 13 C and 1 H spectra, and the standard for 23 Na spectra was a saturated NaCl solution. , Proton decoupled carbon spectra were recorded using single pulse aquisition at 45° pulse angle and 5 s relaxation delay for a 17 h aquisition period. 23 Na NMR spectra were recorded using single pulse acquisition at 10 μs pulse width and 5 s relaxation delay for a given number of acquisitions.…”

Complex Formation between Sugars and the Sodium Cation in Non‐Aqueous Solvents

“…Experimental Part. -The spectra are obtained with vacuum-sealed tubes, as described previously [3]. Analysis of the data proceeds according to the published protocol [I].…”

Non-Covalent Adducts of Sodium Poly(α,L-glutamate) with Poly(N-vinyl pyrrolidone): Methods of Preparation and Characterization of Structure

“…Tetramethylsilane was used as the external standard for obtaining 1 H spectra, and the standard for 23 Na spectra was a saturated sodium chloride solution. [21,22] The 23 Na NMR spectra were recorded using single-pulse acquisition at 10-ls pulse width and 5-s relaxation delay for a given number of acquisitions.…”