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Photomechanical Effects in Ruthenium Sulfoxide Complexes

Jin, Yuhuan
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1372808823

Abstract Details

2013, Doctor of Philosophy (PhD), Ohio University, Chemistry and Biochemistry (Arts and Sciences).
In order to incorporate ruthenium sulfoxide complexes into macromolecules, the complex [Ru(bpy)2pySO-NB]2+ was synthesized, which has the norbornene group covalently attached to the sulfur atom through a peptide linkage. This complex was copolymerized with norbornene at specific ratios by the Ring Opening Metathesis Polymerization (ROMP) method. The obtained copolymers and [Ru(bpy)2pySO-NB]2+ were characterized by UV-Visible absorption spectroscopy, 1H NMR spectroscopy and Transient Absorption spectroscopy. The copolymers yielded the same UV-Visible absorption spectrum as the ruthenium monomer, with the lowest energy MLCT absorption peak at around 370 nm for S-bonded isomer, and around 470 nm for S-bonded isomer in dichloromethane. The isomerization rate was observed to vary with the medium. For S → O isomerization, the rate constant is 5.0 ± 0.7 x 108 s-1 for [Ru(bpy)2pySO-NB]2+ and 2.0 ± 0.1 x 108 s-1 for the poly-{RuII(bpy)2pySO-NB/NB} 1:25 in DCE, respectively. The evidence support the conclusion that the polymer backbone affects the photoisomerization rate constant of [Ru(bpy)2pySO-NB]2+ in the copolymers. Thin films were prepared from the poly-{RuII(bpy)2pySO-NB/NB} copolymers to study the photomechanical effects, and the poly-{RuII(bpy)2pyS-NB/NB} copolymer was used as the control experiment. Under the same irradiation condition with 405nm light, the poly-{RuII(bpy)2pySO-NB/NB} with ratios of 1:25, 1:40 and 1:60 exhibited reversible phototriggered bending towards the light. The poly-{RuII(bpy)2pySO-NB/NB} with the ratio of 1:110 and the poly-{RuII(bpy)2pyS-NB/NB} did not exhibit any photomechanical response upon irradiation. The compound, [Ru(bpy)2pySO](AOT)2 was also dissolved in a Liquid Crystal Networks system, which exhibited different responses upon irradiation with linear polarized light of different polarized directions. In order to reveal the mechanism for the photomechanical effect in the amorphous ruthenium sulfoxide incorporated copolymer systems, nanoindentation techniques were employed to study the mechanical properties of the films associated with each copolymer. The nanoindentation results indicate that the ruthenium linkaged complexes yield a more compact structure, or stiffer in comparison to the underivatized polymers. Further, the photoisomerization of the [Ru(bpy)2pySO-NB]2+ forced the polymer to form an even more compact structure. Hence, a bilayer model was developed to explain the phototriggered bending in the ruthenium sulfoxide complexes incorporated copolymer systems.
Jeffrey Rack, Professor (Advisor)
131 p.
Chemistry
Ruthenium chelating sulfoxide complex; Photochromic; photo-mechanical; nanoindentation; amorphous polymer; ultrafast TA

Recommended Citations

Citations

  • Jin, Y. (2013). Photomechanical Effects in Ruthenium Sulfoxide Complexes [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1372808823

    APA Style (7th edition)

  • Jin, Yuhuan. Photomechanical Effects in Ruthenium Sulfoxide Complexes. 2013. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1372808823.

    MLA Style (8th edition)

  • Jin, Yuhuan. "Photomechanical Effects in Ruthenium Sulfoxide Complexes." Doctoral dissertation, Ohio University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1372808823

    Chicago Manual of Style (17th edition)

ohiou1372808823
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© 2013, all rights reserved.
This open access ETD is published by Ohio University and OhioLINK.