Intramolecular [2 + 2] Photodimerization Achieved in the Solid State via Coordination-Driven Self-Assembly

An
intramolecular [2 + 2] photocycloaddition is achieved in the
organic solid state via self-assembly of Ag­(I) ions and an endo-ditopic bipyridine. The cations aide to organize carbon–carbon
double (CC) bonds attached to the bipyridine for the cycloaddition
reaction. The CC bonds react regioselectively and quantitatively
to afford a photoproduct with edge-sharing four-, five-, and six-membered
rings. Our study demonstrates the first use of a metal–organic
template to direct an intramolecular [2 + 2] photodimerization in
the organic solid state.

本研究通过银(I)离子与内双位点联吡啶的自组装，在有机固态体系中实现了分子内[2+2]光环加成反应。阳离子辅助配位以规整联吡啶所连的碳碳双键（C=C），使其适配环加成反应需求。碳碳双键以区域选择性且定量的方式发生反应，生成带有共用边四元、五元及六元环的光产物。本研究证实，这是首次采用金属有机模板来调控有机固态中的分子内[2+2]光二聚反应。