Accurate determination of the ultrafast proton transfer rate in porphycene using nuclear spin relaxation

Abstract

The longitudinal ¹⁵N relaxation rate and ¹⁵N{¹H} NOE enhancement were determined for porphycene in a CD₂Cl₂ solution. By invoking the rotational diffusion tensor of porphycene as previously determined, these data could be used to evaluate the tautomerization rate of protons in the NHN bridges. The proton transfer rate compares well to the results obtained by other authors by means of optical spectroscopy.