ELECTROCHEMICAL AND PHOTOPHYSICAL PROPERTIES OF 2-COMPONENT COORDINATION-COMPOUNDS CONTAINING A METALLOCYCLAM AND AN RE-I(BIPY)(CO)(3)CL SUBUNIT

The two-component coordination compounds [Re-I(CO)(3)Cl(L)](2+) (L=Ni- II, Cu-II or Zn-II complex of the yl-5'-yl-methyl)-1,4,8,11-tetraazacy clotetradecane ligand) were synthesized and their electrochemical and photophysical properties investigated and compared with those of the s eparate components. The influence on the oxidation potential of the Re I centre of the Cu-II and Zn-II neighbouring cations was found to be n egligible. However, when Ni-II is coordinated by the cyclam ring (cycl am = 1,4,8,11-tetraazacyclotetradecane),its oxidation precedes that of Re-I, with significant consequences on the oxidation potential of the latter. Finally, the fluorescence of the rhenium-containing component was found to be dependent on the cation coordinated by the proximate cyclam ring: in particular, the Ni-II and Cu-II complexes quench the f luorescence completely, and the Zn-II complex does not. (C) 1998 Elsev ier Science S.A. All rights reserved.