Photoinduced water splitting in pyridine water clusters.

Ab initio calculations predict that pyridine (Py) can act as a photo-catalyst to split water by the absorption of a UV photon following the reaction Py-H2O + hν → PyH˙ + OH˙. To test this prediction, we performed two types of experiments: in the first, we characterize the electronic spectroscopy of the PyH˙ radical in the gas phase. In the second, we evidence the reaction through the UV excitation of molecular Py-(H2O)n clusters obtained in a supersonic expansion and monitoring the PyH˙ reaction product. The results show unambiguously that PyH˙ is produced, and thus that water is split using pyridine as a photo-catalyst.