CHARGE-TRANSFER COMPLEXES - PHOTOINDUCED ELECTRON-TRANSFER OF 1,2-DITHIOLENE COMPLEXES OF NICKEL AND PLATINUM

Treatment of the complex [(C6H6)(2)Cr]I with [(n-C4H9)(4)N](2)[MS(4)C(4)(CN)4] (M = Ni, Pt) affords the new compounds {[(C6H6)(2)Cr](2)[MS(4)C(4)(CN)(4)]} (1, M = Ni. 2, M = Pt). Compounds 1 and 2 are identified as charge-transfer (CT) complexes by their absorption and diffuse reflectance spectra. The new CT absorption in the visible region, in the solid state and in non polar solvents is consistent with the formation of contact ion pairs (CIP) in 1 and 2. Accordingly, photoexcitation of the charge-transfer absorption band of the CIPs leads to (C6H6)(2)Cr and [(C6H6)(2)Cr][MS(4)C(4)(CN)(4)] (4, M = Ni; 5, M = Pt) The UV-visible, IR and ESR data for the new complexes are reported and discussed in relation to the charge-transfer photochemistry of contact ion pairs.