Premium
Synthesis, Structure, and DFT Analysis of the THF Solvate of 2‐Picolyllithium: A 2‐Picolyllithium Solvate with Significant Carbanionic Character
Author(s) -
Brouillet Etienne V.,
Kennedy Alan R.,
Krämer Tobias,
Mulvey Robert E.,
Robertson Stuart D.,
Stewart Alexander,
Towie Stephen
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000006
Subject(s) - natural bond orbital , chemistry , deprotonation , crystallography , pyridine , resonance (particle physics) , atoms in molecules , nucleophile , reactivity (psychology) , carbanion , density functional theory , molecule , atom (system on chip) , ring (chemistry) , stereochemistry , yield (engineering) , computational chemistry , ion , medicinal chemistry , organic chemistry , medicine , physics , alternative medicine , materials science , particle physics , pathology , computer science , metallurgy , embedded system , catalysis
Previous studies of different solvates of 2‐methylpyridyllithium (2‐picolyllithium) have uncovered electronic structures corresponding to aza‐allyl and enamido resonance forms of the metallated pyridine‐based compounds. Here, we report the synthesis and characterization of [2‐CH 2 Li(THF) 2 C 5 H 4 N], a new THF solvate. X‐ray crystallographic studies reveal a dimeric arrangement featuring a non‐planar eight‐membered [NCCLi] 2 ring, in which the primary cation‐anion interaction is between the central Li atom and the C atom of the deprotonated methyl group [length, 2.285(2) Å], suggesting a new carbanionic resonance structure for this 2‐picolyllithium series. The significant carbanionic character of [2‐CH 2 Li(THF) 2 C 5 H 4 N] was confirmed by gas‐phase DFT calculations [B3LYP/6‐311+G(d)] with the calculated electron density interrogated by means of quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. For comparison these computational analyses were also performed on the literature structures of [2‐CH 2 Li(2‐Picoline)C 5 H 4 N] and [2‐CH 2 Li(PMDETA)C 5 H 4 N]. In a reactivity study, [2‐CH 2 Li(THF) 2 C 5 H 4 N] was found to undergo nucleophilic addition to pyridine to generate dipyridylmethane in a good yield.