Structural Engineering and Electronic Properties of Halide-Specific Supramolecular Architectures: Effective for Stabilizing H₅O₂⁺and Fabricating Semiconducting Photoresponsive Diodes

Abstract

Two different halides containing chloride-and bromide-assisted dissimilar crystalline supramolecular building blocks of 4′-(1H-imidazol-2-yl)-4,2′:6′,4″-terpyridine (ITP) have been achieved. The dissimilar supramolecular associations with hydrogen-bonded networks have been engineered by the role of halides in the ITP-based crystal systems (i.e., ITP-Cl and ITP-Br for Cl − and Br − , respectively). Hirshfeld surface analyses of these supramolecular assemblies have been performed. The π-systems of protonated pyridine and imidazole rings play a pivotal role in establishing the noncovalent π•••π type supramolecular interactions in both the crystals, and the π-system-directed associations certainly assist in forming the 3D supramolecular architectures of ITP-Cl and ITP-Br in the solid state. Most intriguingly, the supramolecular association of ITP-Cl uniquely stabilizes the cationic unit of hydroxonium hydrate (i.e., H 5 O 2 + ) in the solid state, and such solid-state stabilization of H 5 O 2 + by the imidazole-connected terpyridine-based system is one of the pioneering challenges in crystal engineering. Distinctly, the hydrogen-bonded cluster-like assembly of H 5 O 2 + and Cl − has been observed in the ITP-Cl system through hydrogen donor−acceptor balance. Subsequently, a special drive has been endeavored to unveil the semiconducting features, including the charge transport property and photoresponsive behavior, of these synthesized ITP-Cl and ITP-Br-based devices. Fascinatingly, the chloride-mediated ITP-Cl-based device shows remarkably higher electrical conductivity with respect to the ITP-Br-based device under photoirradiation conditions, and this implies the tuning effect of different halides toward the applicability of thin-film-based device performance. The device efficiency-based experimental outcomes have been rationalized through a density functional theory-level analysis.

Solvent and stoichiometry-dependent versatile organogelation and robust crystallization from the supramolecular association of adipic acid and triethanolamine

“…The normalized contact distance on the Hirshfeld surface is termed as d norm and it is expressed as d norm = ( d i − r i vdw )/ r i vdw + ( d e − r e vdw )/ r e vdw , where r i vdW and r e vdW are the van der Waals radii of the atoms. 43–46 The corresponding 2D-fingerprints of both crystals show a quantitative analysis of the different interactions. The Hirshfeld surface mapping demonstrates the interatomic close connections based on the sum of the spherical electron densities of the atoms constituting the crystal and it was critically explored through the software Crystal Explorer 3.1.…”