RESUMEN
In alkyllithium chemistry the highest reactivity has historically been linked to the smallest degree of aggregation possible. Since tert-butyllithium is known to form a monomer in tetrahydrofuran solution, using just stoichiometric amounts of the lewis base to selectively form a dimeric species seemed irrational. In this study, we showed a considerable increase of the reactivity of t-BuLi when using stoichiometric amounts of THF in the non-polar solvent n-pentane in order to enable the deprotonation of simple methyl silanes and other low C-H-acidic substrates. In this context, we were able to obtain the corresponding aggregates of t-BuLi with the ligand THF in suspension and as crystalline solids and investigate them by single crystal X-ray structural analysis, inâ situ FTIR spectroscopy and quantum chemical calculations. Furthermore, we were able to explain the enhanced reactivity of t-BuLi with stoichiometric amounts of THF on the basis of structural features of the bridged dimer obtained under these conditions. With these findings, we present a new target in the aggregation of alkyllithium reagents: the selectively formed "frustrated" aggregates!
RESUMEN
In the title compound, (2-methyl-idene-1,2-di-hydro-pyridinium-κN)tris-(tetra-hydro-furan-κO)lithium, [Li(C6H6N)(C4H8O)3], the lithium ion adopts a distorted LiNO3 tetra-hedral coordination geometry and the 2-picolyl anion adopts its enamido form with the lithium ion lying close to the plane of the pyridine ring. A methyl-ene group of one of the thf ligands is disordered over two orientations. In the crystal, a weak C-Hâ¯O inter-action generates inversion dimers. A Hirshfeld surface analysis shows that Hâ¯H contacts dominate the packing (86%) followed by Oâ¯H/Hâ¯O and Câ¯H/Hâ¯C contacts, which contribute 3% and 10.4%, respectively.