Role of Intermolecular Interactions in Molecular Packing of Alkoxy-Substituted Bis-1,3,4-oxadiazole Derivatives

Abstract

The molecular packing, intermolecular interactions, and electron-transporting and photophysical properties of a series symmetrical alkoxy-substituted bis-1,3,4-oxadiazole derivatives (BOXD-o-OCH3, BOXD-m-OCH3, BOXD-D1, and BOXD-T1) are carefully investigated through a combination of experimental techniques and theoretical calculations here. The single-crystal structure analysis reveals that all these single crystals exhibit similar layer structures, while their molecular structures, displacement of the nearest adjacent molecules in π-stacking, and molecular packing modes are effectively tuned by changing the positions, amounts, or lengths of alkoxy groups in these compounds. Careful analysis of intermolecular interactions demonstrated that π–π intermolecular interactions are the main forces in the formation of single crystal and that C–H···O intermolecular interactions have a non-negligible contribution in determining the distinguished packing modes of these single crystals. BOXD-o-OCH3-α crystal exhibit a maximum calculated electron mobilities value (5.2 cm2V–1S–1) among these selected crystals. The absorption and emission maxima of these single crystals exhibit different redshifts. In addition, these single crystals also exhibit high fluorescence quantum efficiency. Our investigations would not only provide an effective way to tuning crystal packing but also guide the design of materials with excellent performance in a device.

π–π Noncovalent Interaction Involving 1,2,4- and 1,3,4-Oxadiazole Systems: The Combined Experimental, Theoretical, and Database Study

“…Moreover, the current finding on the π···π interactions involving oxadiazole moieties are important not only for the utilization of medicinal chemistry and drug design. Previously, such oxadiazole-involved stacking interactions were recognized as the properties defining force in several fluorescent materials [ 85 , 86 , 87 , 88 ].…”

Accurate Analysis of Anisotropic Carrier Mobility and Structure–property Relationships in Organic BOXD Crystalline Materials

“…To achieve this goal, a series of symmetric alkoxy-substituted bis-1,3,4-oxadiazole derivatives (BOXD-o, BOXD-m, BOXD-p, BOXD-D, and BOXD-T) (CCDC numbers are 293679, 1448062, 1875779, and 1875781-1875783, respectively) has been chosen, which has been synthesized by Wang et al ( Chen et al, 2019a ). The molecules only differ by their positions of substituents, but the crystal structures formed by these molecules are radically different, even though the molecular skeleton remains largely similar.…”

The Importance of Polymorphism Dependent Aggregation Induced Enhanced Emission of the Acrylonitrile Derivative: Helical J Type and Antiparallel H Type Stacking Modes

“…The polymorphic existence of the studied molecule may depend on noncovalent interactions including intra and intermolecular interactions which are affected by crystallization conditions [35–37] . Therefore, understanding of noncovalent interactions in the polymorphic crystal structures has an important place to analyze structural differences and packing modes between them and their charge transport and photoluminesans behavior in solid phase [38–41] . The performance of organic molecule based devices strongly is related to the molecular‐assembly structures which are created by interactions of whole molecule in the aggeragate state rather than by individual molecule.…”

“…[35][36][37] Therefore, understanding of noncovalent interactions in the polymorphic crystal structures has an important place to analyze structural differences and packing modes between them and their charge transport and photoluminesans behavior in solid phase. [38][39][40][41] The performance of organic molecule based devices strongly is related to the molecular-assembly structures which are created by interactions of whole molecule in the aggeragate state rather than by individual molecule. It is necessary to elucidate the relationship between molecular packing characteristics formed by noncovalent interactions and optoelectronic properties to meet demands about the new molecular organic functional materials.…”