Discrete versus Infinite Molecular Self-Assembly:  Control in Crystalline Hydrogen-Bonded Assemblies Based on Resorcinol

Cocrystallization of 1,2-bis(4-pyridyl)ethane (4,4'-bipyeth) with resorcinol (res), 4-chlororesorcinol (4-Cl-res), and 4,6-dichlororesorcinol (4,6-di-Cl-res) yields molecular solids (4,4'-bipyeth).(res) 1a, 2(4,4'-bipyeth).2(4-Cl-res) 1b, and 2(4,4'-bipyeth).2(4,6-di-Cl-res) 1c with components held together by O-H...N hydrogen bonds. In 1a the components form an infinite 1D polar array, whereas in 1b and 1c the components form 0D four-component complexes. Formation of the discrete assemblies is attributed to peripheral steric effects, which block the solid-state polymerization. [reaction: see text]