Synthesis, structure and packing properties of three Tröger's base analogues containing substituted fluorene units

Abstract

Tröger's base (TB) analogues are important building blocks in molecular engineering due to their C₂ symmetry, concave Λ-shape and chirality. We have synthesized three new TB analogues with aromatic fluorene units substituted by n-butyl or/and bromine groups. The structure and packing properties of these TB analogues have been reported. The weak intermolecular forces involved in the crystal packing varying with the substitutions of the three TB analogues have been analysed and described in detail. Thermal and optical properties have also been provided for additional illustration.