Vibrational spectroscopy of cyclohexylaminoglutethimide in low-temperature matrices, solutions and the solid state

Abstract

The vibrational spectra of cyclohexylaminoglutethimide (CHAG) molecules were studied in low-temperature Ar and N2 matrices and in CCl4, CHCl3, CS2 and CH3CN solutions (at different concentrations). It was found that increasing the solute concentration in CCl4, CS2 and CHCl3 solutions leads to the formation of dimers. On the other hand, in CH3CN solution only the solute–solvent complexes occur.The molecular structure and theoretical IR and Raman spectra of CHAG were predicted with the use of ab initio RHF/6-31G∗∗ and density functional B3LYP/6-31G∗∗ quantum mechanical methods. A comparative analysis of theoretical and experimental spectra of monomeric (isolated) species has led to the assignment of most of the absorption bands in terms of CHAG normal modes.The IR and Raman spectra of crystalline samples (solid film and KBr pellet) were recorded as well. A reliable assignment of the IR and Raman spectra of crystalline CHAG was obtained with the help of theoretically simulated spectra and the results of our earlier investigations of aminoglutethimide and glutethimide vibrational spectra.