Vibrational spectroscopy of glutethimide - From isolated molecule to solid state

The IR and Raman spectra of glutethimide (3-ethyl-3-phenyl-2,6- piperidinedione) were obtained for both monomers and dimers in solution and matrix environment. The IR and Raman spectra were also obtained for the crystalline glutethimide. The spectral assignments were made based on quantum chemical theoretical calculations with the use of RHF and DFT methods and using isotopically labelled derivatives. The Raman spectra seem to be of limited use to study the intermolecular interactions of cyclic imides. The dominant species in diluted solutions of CCl₄, CS₂ and CHCl₃ solutions were the glutethimide monomers. The dimer formation appeared at higher concentration about 0.2% in CCl₄ and CS₂ and 1% in CHCl₃. In CH₃CN solution no dimers were formed. The band corresponding to the v(N-H) stretching vibration was selected as a diagnostic band reflecting hydrogen bonding interactions of glutethimide with the solution, matrix and crystalline environment.