Nonlinear Optical and Related Properties of Iron(II) Pentacyanide Complexes with Quaternary Nitrogen Electron Acceptor Units

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• 作者：Benjamin J. Coe ; Simon P. Foxon ; Elizabeth C. Harper ; James Raftery ; Rachel Shaw ; Catherine A. Swanson ; Inge Asselberghs ; Koen Clays ; Bruce S. Brunschwig ; Anthony G. Fitch
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：February 16, 2009
• 年：2009
• 卷：48
• 期：4
• 页码：1370-1379
• 全文大小：284K
• 年卷期：v.48,no.4(February 16, 2009)
• ISSN：1520-510X

文摘

Three new complex salts Na₂[Fe^II(CN)₅(L)] [L = N-methyl-4-{E,E-4-(4-pyridyl)buta-1,3-dienyl}pyridinium, N-methyl-4-{E,E,E-6-(4-pyridyl)hexa-1,3,5-trienyl}pyridinium, or N-methyl-1,4-bis-{E-2-(4-pyridyl)ethenyl}] benzene have been prepared. These compounds have been characterized by using various techniques including electronic absorption spectroscopy and cyclic voltammetry, allowing their properties to be compared with those of the known complexes where L = N-methylpyrazinium (Mepyz⁺), N-methyl-4,4′-bipyridinium, or N-methyl-4-[E-2-(4-pyridyl)ethenyl]pyridinium. Molecular quadratic nonlinear optical (NLO) responses have been determined by using hyper-Rayleigh scattering (HRS) at 1064 nm, and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d → π* metal-to-ligand charge-transfer (MLCT) bands. The MLCT transitions show large red-shifts on moving from aqueous to methanol solutions, and these excitations are associated with relatively large static first hyperpolarizabilities β₀. Single crystal X-ray structures of two hydrated materials containing the complex anion [Fe^II(CN)₅(Mepyz⁺)]²⁻ have been determined, and both of these show some degree of alignment of the constituent complex dipoles.