The Strong Acidity and the Process for Deprotonation of (eta(6)-Toluene)Fe(H)(2)(SiCl(3))(2)
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Published on: August 17, 2019
Zhengui Yao1, Kenneth J. Klabunde
1Department of Chemistry, Kansas State University, Manhattan, Kansas 66506.
Abstract:
The acidity and the process for deprotonation of (eta(6)-toluene)Fe(H)(2)(SiCl(3))(2) in acetonitrile were studied with pyridine derivatives. (eta(6)-Toluene)Fe(H)(2)(SiCl(3))(2) is a very strong acid and deprotonates in acetonitrile. The formation of hydrogen-bonded complexes M-H.N prior to deprotonation is observed when pyridine, 2,6-lutidine, and 2,2'-bipyridine are used. With 1 equiv of bipyridine, the hydrogen-bonded species is quite stable, two hydrides are deprotonated, and [bpyH(2)](2+) is formed. The small (57)Fe-hydride coupling constant (3.6 Hz) for (eta(6)-toluene)Fe(H)(2)(SiCl(3))(2) is consistent with strong acidity of the compound. The 10.8 Hz coupling between (57)Fe and the hydride in [(eta(6)-toluene)Fe(H)(SiCl(3))(2)](-) and (eta(6)-toluene)Fe(H)(py)(SiCl(3)) is similar to those observed in other Fe(II) hydrido compounds. The observation of the coupling only between p-H and the hydride in [(eta(6)-toluene)Fe(H)(SiCl(3))(2)](-) and (eta(6)-toluene)Fe(H)(py)(SiCl(3)) indicates that the configuration with the hydride trans to p-H is dominant in solution and the rotation of the toluene is not fast at room temperature.
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