A comparison between “second-sphere effects” in the excited state properties of coordination compounds and nonmolecular solids

Abstract

In this paper we compare second-sphere effects as known from the field of photochemistry and photophysics of coordination compounds with similar phenomena in nonmolecular solids. Literature data, as well as new results, especially on cryptates, are used. The similarity between these phenomena in both classes of compounds is much larger than thought at first glance and has been overlooked for the most part. The following effects are considered: the influence of complex encapsulation on the yield of photochemical processes and the thermal quenching temperature of luminescence; the interaction in ion pairs resulting in new energy levels and luminescence quenching; and the influence of electric charges on the position of absorption bands. Since quantitative calculations of these effects are not easy to perform, it is beneficial to discuss information available from different fields of research.