Influence of the Steric Demand of the 2,4,6‐Trialkylphenyl Substituents on the Structures and Reactivity of Diarylzinc

The Grignard reaction of 2,4,6‐tri(tert‐butyl)phenylmagnesium bromide with zinc dichloride in THF yields monomeric bis[2,4,6‐tri(tert‐butyl)phenyl]zinc (1). Due to the steric demand of the tert‐butyl groups 1 has a bent CZnC moiety and the boat‐shaped aryl groups are in a staggered conformation. After the transmetallation of 1 with cesium in a solvent mixture of 1,2‐dimethoxyethane (DME) and toluene (1,2‐dimethoxyethane‐O,O′)cesium [2,4,6‐tri(tert‐butyl)phenolate] (2) is isolated. A polymeric structure is formed in the crystalline state by linkage of these molecules via a Cs‐O bond of the phenolate oxygen atoms and a η6‐coordination of the aryl moiety of another molecule to the cesium cations. Furthermore, in the solid state the cesium cation completes his coordination sphere by bonds to a bidentate ether molecule and by close contacts to a tert‐butyl group of a neighboring molecule.