Structural Characterization of 6-Halo-6-Deoxycelluloses by Direct-Dissolution Solution-State NMR Spectroscopy.

Regioselective modifications of cellulose using activated cellulose derivatives such as 6-halo-6-deoxycelluloses provide a convenient approach for developing sustainable products with properties tailored to specific applications. However, maintaining precise regiochemical control of substituent distribution in 6-halo-6-deoxycelluloses is challenging due to their insolubility in most common solvents and the resulting difficulties in precise structure elucidation by modern instrumental analytical techniques. Herein, an accessible NMR-based approach toward detailed characterization of 6-halo-6-deoxycelluloses, including the determination of the degrees of substitution at carbon 6 (DS), is presented.

Metal-Free C-H Borylation of N-Heteroarenes by Boron Trifluoride.

Organoboron compounds are essential reagents in modern C-C coupling reactions. Their synthesis via catalytic C-H borylation by main group elements is emerging as a powerful tool alternative to transition metal based catalysis. Herein, a straightforward metal-free synthesis of aryldifluoroboranes from BF and heteroarenes is reported.

Atom-Efficient Synthesis of Alkynylfluoroborates Using BF -Based Frustrated Lewis Pairs.

A sterically demanding amine, 1,2,2,6,6-pentamethylpiperidine (PMP), forms a highly reactive Lewis acid-base pair with boron trifluoride. This pair reacts with terminal acetylenes to give the products of C(sp)-H borylation, previously unknown tri- and tetraalkynylboron compounds. Trialkynylfluoroborates can serve as surrogates of alkynyltrifluoroborates for C-C coupling reactions.

[Calculation of the amount of free water molecules in aqueous solutions by means of spectral parameters from the terahertz frequency domain taking into account processes of screening].

In this paper we derive a formula to calculate the amount of free water molecules in solution. Physical values in this formula may be obtained by analyzing the spectra of aqueous solutions in the terahertz frequency range. Formula is derived on the basis of considering water polarization process in electric field.