Preparation and structural characterisation of the cation-π complexes [{(Me 3 Si) 2 NK} · ( t Bu-C 6 H 5 )] 2 and [{(Me 3 Si) 2 NK} · (Me 3 -C 6 H 3 )] 2

Abstract

Two new arene solvates [{(Me₃Si)₂NK} · (^tBu-C₆H₅)]₂ (1) and [{(Me₃Si)₂NK} · (Me₃-C₆H₃)]₂ (2) have been synthesised and characterised in the solid state by single-crystal X-ray diffraction analyses. Each complex was prepared through dissolution of potassium hexamethyldisilazide (KHMDS) in either tert-butylbenzene or mesitylene followed by crystallisation. The crystal structures of both 1 and 2 are composed of dimeric K₂N₂ ring aggregates, where each of the metal centres is solvated by either tert-butylbenzene (1) or mesitylene (2) through η⁶ – cation-π interactions. In addition, the potassium centres within each dimer have a number of intramolecular agostic K ··· C interactions with the methyl groups of the HMDS anion.