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

The preparation and structure of Re-2(dppm)(2)(O2CC6H4-p-NO2)(2)Cl-2, 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 Re-2(dppm)(2)(O2CCH3)(2)Cl-2. The preparation of the complex Re-2(O2CC6H4-p-NO2)(4)Cl-2 is also reported together with its photophysical properties which allows for a comparison of the electronic structures and photophysical states of Re-2(4+) and Re-2(6+) containing complexes having MM configurations sigma(2)pi(4)delta(2)delta(2)* and sigma(2)pi(4)delta(2), respectively. An interesting comparison is also made with the related MM quadruply bonded complexes of molybdenum and tungsten.