2006年10月
Experimental and theoretical evaluation of the charge distribution over the ruthenium and dioxolene framework of [Ru(OAc)(dioxolene)(terpy)] (terpy) 2,2 ': 6 ', 2 ''-terpyridine) depending on the substituents
INORGANIC CHEMISTRY
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- ,
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- 巻
- 45
- 号
- 22
- 開始ページ
- 8887
- 終了ページ
- 8894
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/ic060696i
- 出版者・発行元
- AMER CHEMICAL SOC
A series of ruthenium complexes [ Ru( OAc)( dioxolene)( terpy)] having various substituents on the dioxolene ligand ( dioxolene) 3,5-t-Bu2C6H2O2 ( 1), 4-t-BuC6H3O2 ( 2), 4-ClC6H3O2 ( 3), 3,5-Cl2C6H2O2 ( 4), Cl4C6O2 ( 5); terpy) 2,2': 6'2 ''-terpyridine) were prepared. EPR spectra of these complexes in glassy frozen solutions ( CH2Cl2: MeOH = 95: 5, v/v) at 20 K showed anisotropic signals with g tensor components 2.242 > g(1) > 2.104, 2.097 > g(2) > 2.042, and 1.951 > g(3) > 1.846. An anisotropic value, < g > = g(1) - g(3), and an isotropic g value, < g > [( g(1)(2) + g(2)(2) + g(3)(2))/3](1/2), increase in the order 1 < 2 < 3 < 4 < 5. The resonance between the Ru-II( sq) ( sq = semiquinone) and RuIII( cat) ( cat) catecholato) frameworks shifts to the latter with an increase of the number of electron-withdrawing substituents on the dioxolene ligand. DFT calculations of 1, 2, 3, and 5 also support the increase of the Ru spin density ( RuIII character) with an increase of the number of Cl atoms on the dioxolene ligand. The singly occupied molecular orbitals ( SOMOs) of 1 and 5 are very similar to each other and stretch out the Ru - dioxolene frameworks, whereas the lowest unoccupied molecular orbital ( LUMO) of 5 is localized on Ru and two oxygen atoms of dioxolene in comparison with that of 1. Electron-withdrawing groups decrease the energy levels of both the SOMO and LUMO. In other words, an increase in the number of Cl atoms in the dioxolene ligand results in an increase of the positive charge on Ru. Successive shifts in the electronic structure between the RuII( sq) and RuIII( cat) frameworks caused by the variation of the substituents are compatible with the experimental data.
- リンク情報
- ID情報
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- DOI : 10.1021/ic060696i
- ISSN : 0020-1669
- eISSN : 1520-510X
- Web of Science ID : WOS:000241435300020