Crystal-to-Crystal Transformation from a Chain Polymer to a Two-Dimensional Network at Low Temperatures

摘要

Single-crystal to single-crystal transformations involve cooperative movement of atoms in the solid state.Classical studies by Schmidt et al.on the solid-state reactivity of different polymorphs of cinnamic acid paved the way to understanding topochemical reactions in molecular crystals.In this early work as well as in numerous later examples for dimeriza-tion,cyclization,polymerization,and racemiza-tion photochemical excitation was required to bring about the transformations.Examples of thermally induced topotactic reactions are relatively rare.