Coherent anti-stokes Raman Scattering microspectroscopic kinetic study of fast hydrogen bond formation in microfluidic devices

The kinetics of a key noncovalent, hydrogen bonding interaction was studied in situ using coherent anti-stokes Raman scattering (CARS) microspectroscopy in a microfluidic device. The association of model compounds, pyridine and hexafluoroisopropanol, was quantitatively monitored with submicrometer resolution. Lower limits for the very high formation and dissociation rate constants of the model 1:1 pyridine–hexafluoroisopropanol hydrogen bonded complex in dichloromethane-d₂ were determined to be k₁ > 10⁵ M^–1s^–1 and k_–1 > 333.3 s^–1, respectively.