大压缩下氢键环状二聚体：1-吡咯并[3,2-f]喹啉和 2-(2'-吡啶基)吡咯的情况。

Hydrogen-Bonded Cyclic Dimers at Large Compression: The Case of 1-pyrrolo[3,2-]quinoline and 2-(2'-pyridyl)pyrrole.

机构信息

Faculty of Mathematics and Natural Sciences, Cardinal Stefan Wyszyński University, 01-038 Warsaw, Poland.

Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.

出版信息

Molecules. 2021 Jun 22;26(13):3802. doi: 10.3390/molecules26133802.

DOI:10.3390/molecules26133802

PMID:34206494

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8270273/

Abstract

1-pyrrolo[3,2-]qinoline (PQ) and 2-(2'-pyridyl)pyrrole (PP) are important systems in the study of proton-transfer reactions. These molecules possess hydrogen bond donor (pyrrole) and acceptor (pyridine) groups, which leads to the formation of cyclic dimers in their crystals. Herein, we present a joint experimental (Raman scattering) and computational (DFT modelling) study on the high-pressure behaviour of PQ and PP molecular crystals. Our results indicate that compression up to 10 GPa (100 kbar) leads to considerable strengthening of the intermolecular hydrogen bond within the cyclic dimers. However, the intramolecular N-H∙∙∙N interaction is either weakly affected by pressure, as witnessed in PQ, or weakened due to compression-induced distortions of the molecule, as was found for PP. Therefore, we propose that the compression of these systems should facilitate double proton transfer within the cyclic dimers of PQ and PP, while intramolecular transfer should either remain unaffected (for PQ) or weakened (for PP).

摘要

1-吡咯并[3,2-]喹啉（PQ）和 2-（2'-吡啶基）吡咯（PP）是质子转移反应研究中的重要体系。这些分子具有氢键供体（吡咯）和受体（吡啶）基团，这导致它们在晶体中形成环状二聚体。在此，我们通过实验（拉曼散射）和计算（DFT 建模）联合研究了 PQ 和 PP 分子晶体的高压行为。我们的结果表明，在 10 GPa（100 kbar）的压力下，环状二聚体中的分子间氢键显著增强。然而，分子内的 N-H∙∙∙N 相互作用要么几乎不受压力影响（如在 PQ 中），要么由于压缩诱导的分子变形而减弱（如在 PP 中）。因此，我们提出，这些体系的压缩应有利于 PQ 和 PP 环状二聚体中的双质子转移，而分子内转移要么不受影响（对于 PQ），要么减弱（对于 PP）。