Application of Long-Range Synthon Aufbau Modules Based on Trihalophenols to Direct Reactivity in Binary Cocrystals: Orthogonal Hydrogen Bonding and π-π Contact Driven Self-Assembly with Single-Crystal Reactivity

Abstract

The ability of 2,4,6-trihalophenols (3X-phOH) (where X = F, Cl, or Br) to enable reactivity of 1,2-bis(4-pyridyl)ethylene (bpe) in the solid state via cocrystallization is reported. The trihalophenols display structure behavior defined by infinite face-to-face π···π contacts and hydrogen bonds as pure solids that we show can be transferred to binary cocrystals to organize bpe to undergo a solid-state photodimerization. Cocrystals based on Cl- and Br-halophenols undergo single-crystal-to-single-crystal photoreactions to afford rctt-tetrakis(4-pyridyl)cyclobutane (tpcb) stereoselectively and in near quantitative yield. The use of 3X-phOH to enable reactivity in the solid state is discussed in the context of long-range synthon Aufbau modules.