Observation of doubly ionised metalloporphyrins in the gas phase prepared by femtosecond ionisation

Double ionisation of ruthenium–CO octaethyl porphyrin has been observed in the gas phase by femtosecond sequential 400/800 nm multi-photon excitation. Time resolved measurements show the important effect of femtosecond delayed two colour ionisation in producing efficiently doubly ionised metalloporphyrins. This is related to ultrafast electronic relaxation after the first 400 nm pump laser. The stability of such metallophyrin doubly charged ions is exceptional owing to the ability of the ring and the metal to accommodate two positive charges. These measurements relate to the positive charge distribution in the metalloporphyrin and should allow a detailed investigation of the redox properties of these important molecules.