Synthesis, Structure, and Electronic Properties of RuN6 Dinuclear Ru-Hbpp Complexes

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• 作者：Stephan Roeser ; Mehmed Z. Ertem ; Clyde Cady ; Rainer Lomoth ; Jordi Benet-Buchholz ; Leif Hammarstr枚m ; Biprajit Sarkar ; Wolfgang Kaim ; Christopher J. Cramer ; Antoni Llobet
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：January 2, 2012
• 年：2012
• 卷：51
• 期：1
• 页码：320-327
• 全文大小：454K
• 年卷期：v.51,no.1(January 2, 2012)
• ISSN：1520-510X

文摘

A series of RuN₆ dinuclear Ru鈥揌bpp complexes (Hbpp is the dinucleating tetraaza ligand 3,5-bis(pyridyl)pyrazole) of general formula {[Ru^II(R²-trpy)(MeCN)]₂(渭-R¹-bpp)}³⁺, 10³⁺鈥?b>14³⁺, (R¹ = H, Me, or NO₂. and R² = H, Me, MeO; see Scheme 1) has been prepared from their Cl^{鈥?/sup> or AcO鈥?/sup> bridged precursors. The complexes have been characterized by UV鈥搗is, NMR, CV, and some by X-ray. Complexes 103+鈥?b>143+, Ru₂II,II, were oxidized by 1 equiv in solution, leading to the mixed valence Ru₂II,III complexes 104+鈥?b>144+ containing one unpaired electron and were characterized by EPR and UV鈥搗is鈥搉ear-IR, which showed metal-centered spin and the presence of low-energy IVCT bands. The H_ab parameter indicates a relatively strong electronic coupling between the two ruthenium centers (class II). Further two electron oxidation in solution of the 103+鈥?b>143+ led to the formation of EPR silent Ru₂III,III complexes 105+鈥?b>145+, that were further characterized by UV鈥搗is鈥揘IR. TD-DFT calculations are employed to assign the nature of the UV鈥搗is transitions for the complexes in the various oxidation states, which are of metal to ligand charge transfer (MLCT) type for Ru₂II,II and ligand to metal charge transfer (LMCT) type for Ru₂III,II and Ru₂III,III.}