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Rate constants for electron-transfer reactions of d/sup 9/ metal (Cu(II), Ni(I), and Ag(II)) macrocyclic complexes have been determined by pulse radiolysis. The self-exchange rate constants reveal slow exchanges for d/sup 9/10/ couples (values between 10/sup 3/ and 10/sup -2/ M/sup -1/ s/sup -1/) and fast ones for d/sup 8/9/ couples (values between 10/sup 4/ and 10/sup 9/ M/sup -1/ S/sup -1/). The photochemical oxidation of the macrocyclic ligand in Ag((14)aneN/sub 4/)/sup 2 +/ takes place with larger quantum yields than in the corresponding Cu(II) complex (10/sup -1/ vs 10/sup -3/). No photooxidation of axially coordinated ligands has been detected with Ag(II) complexes. The thermal and photochemical reactivities are discussed in terms of the differences in the electronic levels and nuclear configurations between these d/sup 9/ metal complexes. 37 references, 4 figures, 3 tables. |
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