Mixed valence manganese dimer

Crabtree et al. reported the immobilisation of the dimeric mixed-valence species [(tpy)(H20)Mn (0)2Mn (tpy)(H20)] (5) onto titanium dioxide nanoparticles with different degrees of crystallinity. The complex was directly adsorbed onto the titanium dioxide surface for ciystalline titanium dioxide, the manganese(iii)-manganese(iv) dimer transformed to manganese(iv)-manganese(iv) dimer or tetramer-like structure, whereas it remained stable when anchored to titanium-dioxide nanoparticles with low crystallinity. The o>ygen-evolution measurements performed in the presence of CAN showed that the dimeric mixed-valence complex adsorbed on amorphous titanium dioxide support was not catalytically active, whereas the oxidised/dissociated complex formed in the crystalline titanium dioxide nanoparticles showed catalytic activity however, no detailed explanation was provided for the differences in catalytic activity. ... 

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