Tosylation and acylation of cellulose were performed under mild reaction conditions using imidazolium based ionic liquids (ILs) as solvents. The non-degradative nature, lower viscosity, as well as higher solubility of cellulose in [amim]Cl encouraged us to carry out the reactions in this media. The reactions described here were optimised for this particular solvent in order to obtain different cellulose derivatives with high yields, homogeneity and degree of substitution (DS). Two reagents employed for the in situ activation of carboxylic acids were N,N 0 -carbonyldiimidazole (CDI) and 1-ethyl-3-(3 0 -dimethylaminopropyl)carbodiimide hydrochloride (EDCI). Final products were characterised by solution and solid-state NMR techniques.

A polymer assisted liquid state DOSY NMR technique, to extract the spectra of the individual components from mixtures in CDCl(3), is demonstrated. The enhancement of diffusion coefficient differences is achieved using a soluble polymer, polyvinylpyrrolidone, as the "stationary phase". The "separation" of analytes resembles normal-phase chromatography, for example, TLC. This method provides a fast, cheap, and simple technique to resolve the NMR spectra of complex mixtures.

New phenyl and phenol bis(2‐picolyl)amine (Dpa) derivatives have been synthesized in order to generate zinc chelates for imidazole anion receptors. Previously, binuclear phenolic zinc and copper chelates have shown affinity for pyrophosphate and guanidine anions, respectively. Herein we report significant imidazole affinity increasing from 2.38 × 106 to 2.90 × 107 for phenol‐bridged binuclear zinc–Dpa chelates, as evidenced by dynamic and titration 1H NMR studies. Among the Dpa chelates investigated, the zinc‐coordinated phenol group plays a crucial role in the mechanism of anion binding. Low‐temperature 1H NMR experiments suggest a σν‐symmetric geometry for the imidazole chelate. Computational DFT studies at the B3LYP level of theory imply that imidazole binding displaces the phenol bridge between the zinc ions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

NMR analysis of complex mixtures can be significantly simplified using polyethyleneglycol (PEG) as resolving additive in DOSY NMR technique, which allows the extraction of individual spectra of mixture components with differing polarity. Resolving power of PEG-assisted DOSY was demonstrated with natural product mixtures.

Two organic radical contrast agents, TEMPO-Glc and TEEPO-Glc, were synthesized and their stabilities and contrast enhancing properties were tested with in vitro NMR and MRI experiments. Owing to the glucose moieties in the prepared compounds, this study presents potential candidates for a tumor targeting fully organic contrast agents for MRI.