Infrared-spectroscopic and differential scanning calorimetric studies of the two light-induced metastable states in K 2[Ru(NO 2) 4(OH)(NO)

Abstract

In K 2[Ru(NO 2) 4(OH)(NO)] two light-induced long-living metastable electronic states can be generated similar to those in Na 2[Fe(CN) 5NO]·2H 2O. The trans-effect of the OH ligand raises the decay temperature of state II, which is necessary for the use as information storage elements. The intramolecular vibrations are investigated by means of infrared spectroscopy. The frequencies of the internal modes ν (OH), ν (NO), δ(RuNO), ν (RuN) are shifted to lower energies, whereas the δ(RuOH) vibration is shifted to higher frequencies. The new electronic configuration is studied by the thermal induced decay with differential scanning calorimetry, yielding the decay temperature, the activation energy, the frequency factor, the order of reaction and the energetic position of the new states relative to the ground state. Further, state I can be transferred into state II by irradiation of the crystal with light of a Nd-YAG laser (1064 nm).