Infrared and NMR studies of probes in binary solvent systems
The spectra of a variety of probe molecules have been measured for 1ci concentrations in a range of pure and mixed solvents . These include triethyiphosphine oxide [Et3PO: 'P and vpo] , trimethylphosphate [3POL,: p \poJ ' hexamethyiphosphoramide [HMPA: 'P and VpQ], acetone and various esters [ C and vco} and cyancinethane [MecN : ' , and VCNJ . Infrared spectra often reveal the presence of several different transns, indicating the presence of well-defined solvates . Hence for solutions in protic solvents it can be shcn that tn, diand mono— solvates 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.