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The effects of anchoring groups on electron injection from adsorbate to nanocrystalline thin films were investigated by comparisons injection kinetics through carboxylate versus phosphonate groups to Ti[O.sub.2] and Sn[O.sub.2]. The anchoring groups were shown to have negligible effects on the energetics of relevant orbitals in the Re complexes.

The photolysis of CpW(CO)(sub 3)Me is demonstrated to produce methyl radicals and to cleave DNA in a single-stranded manner, and preliminary evidence implicated a carbon-centered radical in this process. The mechanism of strand scission in this reaction was determined to occur by hydrogen atom abstraction from the 4'- and 5'-positions of the deoxyribose moiety of the backbone of DNA.

The dependence of Re(L(sub p))(CO)3Cl (or ReClP) [Lp = 2,2'-bipyridine-4,4'-bis-CH2PO(OH)2] and Re(LA)(CO)3Cl (or ReClA) [L(sub A)=2,2'-bipyridine-4,4'-bis-CH2COOH] sensitized TiO2 and ReClP sensitized SnO2 nanocrystalline thin films is examined. Results suggests that the observed pH-dependent electron transfer rate can be qualitatively accounted for by considering the change of density of electron-accepting states caused by the pH-dependent conduction band edge position.

Several derivatives of endo-1-Cr were synthesized, and the dynamic stereochemistry of endo-(starphenylene) chromium tricarbonyl, endo-1-Cr, was analyzed through NMR spectroscopic techniques. Ab initio calculations and NMR experimental findings prove the existence of impaired rotation around the metal-arene bond and intramolecular metal-arene migration chemistry. The first molecules to show smooth metal-arene exchange and comparatively impaired tripod rotation are the derivatives of endo-(starphenylene) chromium tricarbonyl (endo-1-Cr)t-10.

Research has been conducted on the photoinduced DNA cleavage. Results indicate that this cleavage occurs upon the photolysis of such complexes as CpM(CO) (sub)n R, where M= W and Fe and R= CH (sub)3, C (sub)6 H (sub)5 but not when M= Cr or Mo.

The exciton dissociation dynamics of CdSe quantum dots (QDs) adsorbed with Re[(CO).sub.3]Cl(dcbpy) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) (ReC0A) is reported. The results showed that the electron transfer rate could be controlled by varying the size of QDs.

The article shows that the DNA damage by MoC[H.sub.3]([[eta].sup.3]-allyl)[(CO).sub.2](phen) complexes occurs by two mechanisms. Backbone cleavage via the abstraction of H1' and H5' from the deoxyribose moiety and base modification have resulted in G-specific cleavage through the formation of base-labile residues methylguanine, methoxyguanine and 8-oxo-G.

The formal DNA hydrolysis of various phosphodiester groups by mono- and dinuclear iron complexes is described.

The action of photogenerated methyl radical on a DNA/histone assembly in air has resulted in dissociation of the biomolecular complex because of side-chain modifications including the conversion of lysine amines into aldehyde groups. Histone charge and the level of chromatic condensation have played a vital role in regulating gene expression and have led to protein-DNA dissociation, which has caused significant cellular effects.

A systematic and quantitative investigation of the relative rates of photoinduced interfacial electron transfer as a function of methylene bridge length in the short-bridge limit is accomplished. In the study conducted, the ultra fast infrared spectroscopic investigation of electron injection from a rhenium complex to a SnO2 nanocrystalline film as a function of bridge length is discussed. A novel time-scaling technique to compare kinetic traces allowed the comparison of the nonexponential injection times.

DNA damage by MoCH3(n3-allyl)(CO)2(phen) complexes has been shown to occur by two mechanisms: by backbone cleavage via the abstraction of Hi′ and/or H5′ from the deoxyribose moiety and by base modification, resulting in G-specific cleavage via the formation of base-labile residues methylguanine, methoxyguanine, and 8-oxo-G. [ABSTRACT FROM AUTHOR]

The photolysis of CpW(CO)3Me has been shown to produce methyl radicals and to cleave DNA in a single-stranded manner, and preliminary evidence implicated a carbon-centered radical in this process. In this work, the mechanism of strand scission in this reaction was determined to occur by hydrogen atom abstraction from the 4′- and 5′-positions of the deoxyribose moiety of the backbone of DNA. Additionally, in a side reaction that does not lead to frank strand scission, all four bases of DNA are methylated under these conditions; however, none of these base or backbone modifications lead to the formation of abasic sites. [ABSTRACT FROM AUTHOR]

Abstract: DNA strand scission is produced by the ambient light photolysis of CpFe(CO)2Ph and H2O2, a result that shows potential as a means of targeting tumors, due to the high levels of hydrogen peroxide in cancer cells. This cleavage process is dependent on the concentration of both CpFe(CO)2Ph and H2O2, and preliminary experiments implicate both carbon-centered radicals and reactive oxygen species. [Copyright &y& Elsevier]