Weak interactions induce asymmetry in the crystal structures of triaryl derivatives of group 14 elements

Abstract

A search of the CSD shows that 42% of compounds of type Ph₃EX (E = group 14 element, X = halogen) possess more than one molecule in the asymmetric unit (Z′ > 1). This phenomenon is rationalised in terms of CH⋯X hydrogen bonding and confirmed by the preparation of Ph₃GeI. A remarkable Z′ = 4 structure of Ph₃GeCl is shown to arise from site-selective inclusion of Ph₃GeH impurity.