Concerning the photophysical properties of Re24+ and Re26+carboxylate compounds

Abstract

The preparation and structure of Re₂(dppm)₂(O₂CC₆H₄-p-NO₂)₂Cl₂, where dppm = Ph₂PCH₂PPh₂, is reported together with its photophysical properties (absorption, steady state emission, fs- and ns-transient absorption spectroscopy) and electrochemistry. These data are compared with photophysical studies on the previously reported Re₂(dppm)₂(O₂CCH₃)₂Cl₂. The preparation of the complex Re₂(O₂CC₆H₄-p-NO₂)₄Cl₂ is also reported together with its photophysical properties which allows for a comparison of the electronic structures and photophysical states of Re₂⁴⁺ and Re₂⁶⁺ containing complexes having MM configurations σ²π⁴δ²δ^*2 and σ²π⁴δ², respectively. An interesting comparison is also made with the related MM quadruply bonded complexes of molybdenum and tungsten.