Intermolecular H···O═C bonds induced 2D self‐assembly of thiophene based diketopyrrolopyrrole derivative

Abstract

Compounds with diketopyrrolopyrrole (DPP) and thiophene moieties have attracted considerable attention because of their promising charge transport properties. The molecular conformation and self-assembly of 2,5-dihexadecyl-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (TDPP-C16) molecule have been investigated by scanning tunneling microscopy and density functional theory alculation. The TDPP-C16 molecules adsorb with their optimized S-shaped conformation and form a zipper-like pattern on highly oriented pyrolytic graphite surface. R and S rotated structures are observed. The nanostructure is dominated by intermolecular double hydrogen bonds between C═O of the DPP units and hydrogen atom of thiophene rings in the neighboring molecules in each row. Atomic force microscopy and density functional theory calculation also display the existence of strong intermolecular hydrogen bonding. The results provide molecular evidence for the intermolecular interactions of the surface structure, which could benefit to the design of the organic semiconducting materials and understanding of underlying principle of charge transfer process.

A comparative analysis of symmetric diketopyrrolopyrrole‐cored small conjugated molecules with aromatic flanks: From geometry to charge transport

“…However, the weak intermolecular HBs between lactam oxygen and the hydrogen of Th flank in N ‐disubstituted DPP were proposed as the driving force for the self‐assembly on highly oriented pyrolytic graphite surface . Such bonds are usually longer (2.25 Å) as compared to HBs stabilizing 3D network in N ‐unsubstituted DPPs (1.873 Å) …”

“…As seen, the molecular geometry is not changed for the trans‐trans conformers in crystalline phases. The molecular crystals in this case are stabilized by π‐π stacking interactions of the conjugated backbones and van der Waals attractions between the alkyl substituents, and additionally hold together by weak CH—π contacts or by HBs between lactam oxygen and hydrogens of aryl flanks . None of these interactions, however, influences the conformational properties of the DPP cores, which remain planar in trans‐trans state.…”

Hydrogen Bonds Control Single-Chain Conformation, Crystallinity, and Electron Transport in Isoelectronic Diketopyrrolopyrrole Copolymers

“…The minimum energy conformations of ThDPPTh and TzDPPTz differ in the orientation of sulfur in the thiophene and thiazole rings. Such “conformational lock” based on the hydrogen bond between the proton on the thiophene unit and the carbonyl oxygen of the DPP core is known for ThDPPTh and causes a N,S- syn orientation. , This locking effect cannot occur for TzDPPTz, where CH is replaced by the isoelectronic N. Instead, the electron lone pair at N results in an unfavorable electrostatic interaction with the carbonyl oxygen of the DPP core in the N,S- syn orientation. For the corresponding N,S- anti orientation of TzDPPTz, however, a “conformational lock” due to an attractive interaction between that lone pair and the protons of the methylene group of the aliphatic side chain appears possible when considering the partial charges and rotation of the methyl group.…”

Adlayers of Acceptor Blocks Based on Diketopyrrolo-Pyrrole on Graphite: Self-Assembly and Structure Revealed in All-Atom Modelling

“…Хотя подавляющее большинство этих публикаций посвящено 3D фазам DPP, 2D молекулярная самосборка в адсорбционных слоях [1,13,15,[19][20][21][22][23] заслуживает особого внимания. Прежде всего, слои могут служить удобными и простыми моделями для изучения морфологии.…”

“…Как показывает обзор литературы, в экспериментальнотеоретических статьях сообщается о некоторых закономерностях самосборки диарил-DPP на графите [1,19,20,22]. В этих публикациях приводятся расчеты теории функционала плотности либо изолированных молекул, либо взаимодействующих пар молекул.…”