Structure of [1.1]Ferrocenophanyllithium in the Solution and the Solid State. Absence of an Intramolecular [C-H-C]- Hydrogen Bond

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• 作者：Per Ahlberg ; Ö ; jvind Davidsson ; Martin Lö ; wendahl ; Gö ; ran Hilmersson ; Annika Karlsson ; and Mikael Hå ; kansson
• 刊名：Journal of the American Chemical Society
• 出版年：1997
• 出版时间：February 19, 1997
• 年：1997
• 卷：119
• 期：7
• 页码：1745 - 1750
• 全文大小：373K
• 年卷期：v.119,no.7(February 19, 1997)
• ISSN：1520-5126

文摘

[1.1]Ferrocenophanyllithium (1) is shown bydynamic NMR (DNMR) and isotopic perturbation to undergoa rapid intramolecular 1,12-proton transfer coupled with 1,12-lithiumion transfer. The first [C-H-C]^-hydrogenbond previously reported to be present in 1 is shown byX-ray crystallography to be absent in the solid state.The¹³C NMR spectrum of the bridge-labeled compound[1,12-¹³C₂][1.1]ferrocenophanyl[1-⁶Li]lithium(6) in 2,5-dimethyltetrahydrofuran (DMTHF) displays a 1:1:1 triplet(¹J(¹³C,⁶Li) =4.0 Hz) showing that ⁶Li is bonded to C-1and that 1 is monomeric. Transient nuclear Overhausereffects (tNOE's) measured in DEE-d₁₀ inbridgedmonodeuterated 1 show that the bridges in 1 aresyn and not anti to each other and that lithiumis exo-coordinatedto the anionic bridge carbon. The¹J(¹³C,¹H) couplingconstants show that the hybridization of the carbanioniccarbon is intermediate between sp² and sp³.Thus the solution and solid state structures of 1 aresimilar. UV-visspectroscopy shows that 1 exists mainly as contact ion pairs(CIPs) in the temperature range -100 to +25 C inTHF, DMTHF, and diethyl ether (DEE). In dimethoxyethane (DME),1 is mainly CIPs above +25 C but is mainlyseparated ion pairs (SIPs) below -30 C.