Synthesis, structure and luminescence of Co-crystals with hexagonal channels: arranging disposition and π–π interactions

Abstract

Co-crystallization of asymmetric building blocks 5-(4-pyridyl)pyrimidine (A) and 5-(4-(1-imidazolyl)phenyl)pyrimidine (B) with resorcinol and hydroquinone, respectively, was investigated. Four new organic co-crystals (1–4) were generated. The X-ray single crystal analysis indicates that the crystal packing in 1, 2 and 4 generates open hexagonal channels with resorcinol or hydroquinone molecules encapsulated through hydrogen bonding interactions. In 3, {B₂(resorcinol)₂} macrocycle is generated from clip-like resorcinol and asymmetric B molecules. In addition, the luminescent properties of A, B and 1–4 were investigated primarily in the solid state. The luminescent property is dependent on the molecular vertical arranging disposition and the intermolecular π–π contacting characteristic. The results display more interesting tunability of the emission intensity of the building modules by the incorporation of coformers into the co-crystals.