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Photochemistry and Photophysics of Octahedral Ruthenium Complexes

Sgambellone, Mark Allan
http://rave.ohiolink.edu/etdc/view?acc_num=osu1366111201

Abstract Details

2013, Doctor of Philosophy, Ohio State University, Chemistry.
The photo-induced ligand loss of the complexes [Ru(tpy)(AN)3]2+ and cis-[Ru(tpy)(AN)2Cl]+ (tpy = 2,2`:6`2``-terpyridine) and [Ru(tpy)(5CNU)3]2+ was studied in water and in CH2Cl2 in the presence of chloride from tetrabutylammonium chloride (TBACl). [Ru(tpy)(5CNU)3]2+ is not soluble in CH2Cl2. Photolysis in CH2Cl2 in the presence of chloride ions leads to the dichloro photoproduct trans-[Ru(tpy)(AN)Cl2], and photolysis in water led to the diaqua photoproduct trans-[Ru(tpy)(AN)(H2O)2]2+ or trans-[Ru(tpy)(5CNU)(H2O)2]2+. The two axial ligands are replaced, while the equatorial ligand remains coordinated to the metal. For cis-[Ru(tpy)(AN)3]2+ and [Ru(tpy)(5CNU)3]2+ the axial ligands were replaced in a step-wise fashion, forming an intermediate with one axial acetonitrile ligand. All three complexes were shown to bind to DNA upon photolysis by gel electrophoresis, but not in the absence of light, indicating potential as anti-tumor agents for use in photodynamic therapy (PDT). cis-[Ru(tpy)(AN)2Cl]+ has a higher quantum yield of ligand substitution and a lower energy metal to ligand charge transfer (MLCT) transition showing binding to DNA when irradiated at 650 nm, within the ideal PDT window of 600-850 nm. The low temperature emission and photolysis of [Ru(bpy)3]2+, cis-[Ru(bpy)2(AN)2]2+, cis-[Ru(bpy)2(MeBN)2]2+, and cis-[Ru(bpy)2(py)2]2+ was studied to explore their excited state properties. The emission of [Ru(bpy)3]2+ is known to take place from the 3MLCT state, with a temperature dependence resulting from a thermally accessible non-emissive triplet ligand field state higher in energy than the 3MLCT state. A decrease in emission quantum yield and comparable increase in the quantum yield of photolysis is observed for [Ru(bpy)3]2+ with increasing temperature. This behavior led to the conclusion that the population of the 3LF from the 3MLCT state preceded photosubstitution. The temperature dependence of the emission of the related compounds cis-[Ru(bpy)2L2]2+, where L is AN, MeBN and py, was found to be different from the temperature dependence of the photolysis, suggesting that the photosubstitution proceeds through a different mechanism. One possibility is that the 3LF state is populated directly from the initially excited state and does not require population through the 3MLCT state.
Claudia Turro (Advisor)
Yiying Wu (Committee Member)
Patrick Woodward (Committee Member)
162 p.
Chemistry
Ruthenium; photolysis; photochemistry; Photodynamic Therapy; PDT

Recommended Citations

Citations

  • Sgambellone, M. A. (2013). Photochemistry and Photophysics of Octahedral Ruthenium Complexes [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366111201

    APA Style (7th edition)

  • Sgambellone, Mark. Photochemistry and Photophysics of Octahedral Ruthenium Complexes. 2013. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1366111201.

    MLA Style (8th edition)

  • Sgambellone, Mark. "Photochemistry and Photophysics of Octahedral Ruthenium Complexes." Doctoral dissertation, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366111201

    Chicago Manual of Style (17th edition)

osu1366111201
731
© 2013, some rights reserved.Creative Commons License Photochemistry and Photophysics of Octahedral Ruthenium Complexes by Mark Allan Sgambellone is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.