Cyanamide as an Infrared Reporter: Comparison of Vibrational Properties between Nitriles Bonded to N and C Atoms
2018 121st KCS General Meeting
β-cyanamidoalanine 1 and p-cyanamidophenylalanine 2 were synthesized. The vibrational properties of their CN stretch mode were studied using FTIR and femtosecond IR pump−probe spectroscopies. Aromatic cyanamide 2 shows a complicated lineshape of the FTIR spectrum, which arises from the accidental Fermi resonance, and can be substantially simplified by deuteration of the cyanamide (NHCN) into NDCN group. The transition dipole strengths of the cyanamide group are larger than those of the nitrile (CN) group, but comparable to those of the azido (N3) and isonitrile (NC) groups. The vibrational lifetimes of the cyanamide group are similar to those of the nitrile and azido groups, but shorter than those of the isonitrile group. Cyanamide has the potential to be a good IR reporter of the conformational and environmental structure and dynamics of biomolecules in complementary to nitrile.