Determining the structure of α-phenylethyl isocyanide in chloroform by VCD spectroscopy and DFT calculations—simple case or challenge?

The present work provides a comprehensive theoretical and experimental study of the vibrational circular dichroism of (S)-α-phenylethyl isocyanide in chloroform. The structure in solution is investigated systematically by density functional theory calculations starting from the isolated molecule and then by considering solvent effects implicitly using the PCM and explicitly by taking into account molecular complexes of the isocyanide molecule and chloroform. Furthermore, the influence of dimerisation is evaluated, and it is finally found that the structure of (S)-α-phenylethyl isocyanide in chloroform is best described assuming a solvated dimer. These results are underlined by a quantitative correlation of the experimentally and theoretically obtained rotational strengths and a robust modes analysis.