Negative hyperconjugation control of acidities in α-trimethylsilyl substituted α-picolines: isolation of [Li{NC5H4-2-C(H)(SiMe3)2}{NC5H4-2-C(H)(SiMe3)}]2

Cameron Jones, Colin H.L. Kennard, Colin L. Raston, Graham Smith

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Abstract

Isolation of [{Li(R′H)(R)}2] (1) (R- = NC5H4-2-CH(SiMe3), R′H = NC5H4-2-RH(SiMe3)2), where R′H acts as an N-donor and R- as an η3-aza-allyl unit to one metal centre and an N-bridge to the other (X-ray structure determination), and formation of [{Li(R)(tmeda)}2] and R′H on treatment of (1) with tmeda (= N,N,N′,N′-tetramethylethylenediamine) establishes the relative solution thermodynamic acidities RH > R′H, rationalized by negative hyperconjugation in RH overriding extra polarization from two silicon centres in R′H.

Original languageEnglish
JournalJournal of Organometallic Chemistry
Volume396
Issue number2-3
DOIs
Publication statusPublished - 16 Oct 1990
Externally publishedYes

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