Ion-pair charge transfer complex with near-IR absorption: Synthesis, crystal structure and properties of [Hb]₂[Cu(mnt)₂] (Hb = 1-(4-((1H-imidazol-1-yl)methyl)benzyl)-1H-imidazol-3-ium)

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• 作者：Ravada Kishore^a ; Bharat Kumar Tripuramallu^a ; Gummadi Durgaprasad^a ; Samar K. Das ; ^a ; ^{skdsc@uohyd.ernet.in}
• 关键词：Ion-pair complex ; Near-IR absorption ; Crystal structure ; Supramolecular chemistry
• 刊名：Journal of Molecular Structure
• 出版年：2011
• 出版时间：29 March 2011
• 年：2011
• 卷：990
• 期：1-3
• 页码：37-43
• 全文大小：768 K

文摘

The compound [Hb]₂[Cu(mnt)₂] (1) [Hb = 1-(4-((1H-imidazol-1-yl)methyl)benzyl)-1H-imidazol-3-ium] has been synthesized, starting from 1,4-bis((1H-imidazol-1-yl)methyl)benzene, cupric chloride, and Na₂mnt in methanol. Compound 1 crystallizes in monoclinic system with C2/c space group. In the crystal structure, the interactions between cations and anions via bifurcated CH···(NC-mnt)₂ hydrogen bonds give rise to a two dimensional supramolecular network. It has also been observed that two cation moieties (Hb) are attached together by a very short CH···N hydrogen bonding interaction with H···N distance of 1.74 Å, CHN bond angle of 174.9°. Compound 1 is additionally characterized by cyclic voltammetry, UV–Vis, IR, ¹H NMR and EPR spectroscopy. The ion-pair compound 1 shows an intense absorption in the near-IR region at 1214 nm which has been described as a charge transfer band from HOMO of the copper dithiolate anion [Cu(mnt)₂]²⁻, to LUMO of the [Hb]⁺ cation. The title compound exhibits an oxidative response at +0.46 V vs. Ag/AgCl and a reductive event at −0.67 V vs. Ag/AgCl.