Infrared and NMR studies of probes in binary solvent systems

Abstract

The spectra of a variety of probe molecules have been measured for low concentrations in a range of pure and mixed solvents. These include triethylphosphine oxide [Et3PO: 31P and Vpo], trimethylphosphate [Me3P04: 31P and Vpo], hexamethylphosphoramide [HMPA: 31P and Vpo] acetone and various esters [13C and Vco] and cyancmethane [MeCN: 13C, 14N and vcn]. Infrared spectra often reveal the presence of several different transitions, indicating the presence of well-defined solvates. Hence for solutions in protic solvents it can be shown that tri-, di- and monosolvates may be present, as well as non hydrogen-bonded species. For given binary solvent mixtures (protic and aprotic) the relative concentrations of these solvates are estimated. Hence, in certain cases, trends in NMR shifts for the probes can be reproduced using the infrared data and, hence, unambiguous interpretations can be found. © 1986, Walter de Gruyter. All rights reserved.