Crystal Engineering Organic Semiconductors

Theoretical study on molecular packing and electronic structure of bi-1,3,4-oxadiazole derivatives

“…p-orbitals, which could contribute a lot to the charge carrier mobility and nd potential application in organic eld effect transistors (OFETs). 26,44 The molecular packing corresponding to M3(1.0, 7.2) is very close to the structure found in the crystal (Fig. 7, bottom).…”

“…Until recently, great progress has been made by empirical correction for long-range dispersion effect (DFT-D) 24 or doubling the amount of non-local exchange (M062x), 25 which are based on different idea, but both yield quite well results. And for the experimental case, it is usually hard to get the detailed structural information, except some valuable results obtained from single crystals [26][27][28][29][30][31][32] and Langmuir-Blodgett lms. 33,34 Even so, these static structures observed in experiment, for example in single crystal X-ray diffraction, are generally obtained by chance.…”

Strengthening π–π Interactions While Suppressing Csp2–H···π (T-Shaped) Interactions via Perfluoroalkylation: A Crystallographic and Computational Study That Supports the Beneficial Formation of 1-D π–π Stacked Aromatic Materials

“…The benzene ring π−π interaction here is blocked by steric interactions of the four perfluorobutyl groups. Except for compound 1, the other four compounds show both herringbone (2, 4) and lamellar (3,5) π−π stacking structures with various interplanar distances, indicating that this π−π weak interaction could be dominant if other intermolecular interactions are relatively weaker or prohibited by electronic and/or steric effects of the perfluoroalkyl functional groups.…”

“…3,4 However, the formation of these 1-D and 2-D π−π stacking structures from small molecules via molecular design is still a significant challenge in crystal engineering and organic semiconductor fields. 5 Because organic semiconductor molecules are generally neutral molecules, weak intermolecular interactions and the shape of the molecule are the dominant factors controlling crystal packing. 6 These weak intermolecular interactions typically involve hydrogen bonding, π−π interactions, dipole−dipole interactions, dipole−π interactions, and dispersion interactions (London forces).…”

Stable 5,5′-Substituted 2,2′-Bipyrroles: Building Blocks for Macrocyclic and Materials Chemistry

“…The successful preparation of such a quaterpyrrole prompted us to generalize this synthetic methodology, giving a straightforward access to substituted bipyrroles 3 bearing aromatic and unsaturated moieties at positions 5,5′ (Scheme ). The conjugated structure and the presence of the bipyrrolic moiety make these new molecules of interest in the design of metal ligands, − macrocyclic receptors, ,,− molecular electronics, light-emitting diodes, electrochromic devices, molecular wires, the preparation of conjugated low band gap polymers, − and polymer-based sensors. − …”