Vibrational relaxation dynamics of a potential local infrared probe: Isocyanate

Abstract

Isocyanates are widely used in the production of foams, fibers, coatings, and elastomers. Herein, we use linear and nonlinear infrared spectroscopic methods to study the spectral and dynamical properties of a model compound, benzyl isocyanate. We found that the asymmetric stretching vibrational band of the isocyanate functional group has a significant extinction coefficient and locates in an uncongested region of the IR spectrum. While the frequency of this vibrational band only shows a modest dependence on solvent polarity, its dynamics is rather sensitive to the solvent. These results show that the isocyanate group could be used as a site-specific IR probe of local environments.