Photoredox-Reaktionen

Abstract

In a general part of the present article, the terms redox reaction, photoredox reaction, reduction degree, oxidation number, and charge as well as heterogeneous photoredox systems and photoelectrochemical devices are discussed from a phenomenological and from a quantumchemical point of view. In the second part quantitative photochemical experiments on metal-loaded zeolites are reported, in particular photoinduced oxygen and chlorine evolution from aqueous dispersions of Ag^⊕-zeolites. Selfsensitization is explained. Furthermore quantumchemical and FTIR spectroscopic studies on metal-loaded zeolites are outlined. Due to the uncertainty principle a problem arises regarding the Cu^⊕ in a 6-6 SBU. Orbital stabilization and destabilization are interpreted on dimers which can be described in a first order approximation by (ns,ms;σ_g,σ_u) configuration. Ideas are presented which could lead to a better parametrization of the EHMO model for semiempirical metal cluster calculations. The interaction of Ag with CO₂ is briefly discussed and finally also the result of a MO calculation on a (phenyl-terpyridine)₂Fe^II complex which consists of 81 atoms, to demonstrate that properties of very large molecules can be calculated by means of molecular orbital methods.