Cyclic hydrogen-bonded structures are common motifs in biological systems, providing structural stability and mediating proton transfer for redox reactions. The mechanism of proton transfer across hydrogen-bonded interfaces depends on the strength of the intermolecular coupling between bridging OH/NH vibrational modes. Here we present a novel ultrafast continuum mid-IR spectroscopy experiment to study the vibrational dynamics of the 7-azaindole-acetic acid (7AI-Ac) heterodimer as a model system for asymmetric cyclic hydrogen-bonded structures. In addition to spreading of the excitation across the whole OH band within the time resolution of the experiment, excitation of a 300 cm(-1) region of the ∼1000 cm(-1) broad OH stretching mode of the acetic acid monomer leads to a frequency shift in the NH stretching mode of the 7AI monomer. This indicates that the NH and OH stretching modes located on the two monomers are strongly coupled despite being separated by 750 cm(-1). The strong coupling further causes the OH and NH bands to decay with a common decay time of ∼2.5 ps. This intermolecular coupling is mediated through the hydrogen-bonded structure of the 7AI-Ac heterodimer and is likely a general property of cyclic hydrogen-bonded structures. Characterizing the vibrational dynamics of and the coupling between the high-frequency OH/NH modes will be important for understanding proton transfer across such molecular interfaces.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jp406441r | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Quantum Chemical NMR Spectroscopic Structural Analysis in Solution: The Investigation of 3-Indoleacetic Acid Dimer Formation in Chloroform and DMSO Solution.
Magn Reson Chem
January 2025
Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro, Brazil.
We present a DFT-PCM NMR study of 3-indoleacetic acid (3-IAA), used as a working example, including explicit solvent molecules, named PCM-nCHCl, PCM-nDMSO (n = 0, 2, 4, 8, 14, 20, and 25), to investigate the dimer formation in solution. Apart from well-known cyclic (I) and open (II) acetic acid (AA) dimers, two new structures were located on DFT-PCM potential energy surface (PES) for 3-IAA named quasicyclic A (III) and quasicyclic B (IV), the last one having N-H…O hydrogen bond (instead of O-H…O). In addition, four other structures having π-π type interactions named V, VI, VII, and VIII were also obtained completing the sample on the PES.
View Article and Find Full Text PDFCo(II)-Based 2D Coordination Polymer Featuring Energy Storage and Detection of Aqueous Inorganic Anions.
ACS Omega
January 2025
Department of Applied Chemistry, ZHCET, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh, Uttar Pradesh 202002, India.
Herein, we have synthesized a Co(II)-based 2D coordination polymer [Co(5-AIA)(Imidazole)] () (AIA = 5-aminoisophthalic acid) via a solvothermal approach. SCXRD (single-crystal X-ray diffraction) was utilized to analyze the crystal structure of fabricated . Moreover, PXRD, TGA, FTIR, and SEM analyses were done to identify the structural features of fabricated .
View Article and Find Full Text PDFLong-Range Proton Channels Constructed via Hierarchical Peptide Self-Assembly.
Adv Mater
December 2024
Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel.
The quest to understand and mimic proton translocation mechanisms in natural channels has driven the development of peptide-based artificial channels facilitating efficient proton transport across nanometric membranes. It is demonstrated here that hierarchical peptide self-assembly can form micrometers-long proton nanochannels. The fourfold symmetrical peptide design leverages intermolecular aromatic interactions to align self-assembled cyclic peptide nanotubes, creating hydrophilic nanochannels between them.
View Article and Find Full Text PDFHF Trimer: A New Full-Dimensional Potential Energy Surface and Rigorous 12D Quantum Calculations of Vibrational States.
J Phys Chem A
November 2024
Department of Chemistry, New York University, New York, New York 10003, United States.
HF trimer, as the smallest and the lightest cyclic hydrogen-bonded (HB) cluster, has long been a favorite prototype system for spectroscopic and theoretical investigations of the structure, energetics, spectroscopy, and dynamics of hydrogen-bond networks. Recently, rigorous quantum 12D calculations of the coupled intra- and intermolecular vibrations of this fundamental HB trimer ( , , 234109) were performed, employing an older ab initio-based many-body potential energy surface (PES). While the theoretical results were found to be in reasonably good agreement with the available spectroscopic data, it was also evident that it is highly desirable to develop a more accurate 12D PES of HF trimer.
View Article and Find Full Text PDFA Hydrogen-Bonded, Hexagonally Networked, Layered Framework with Large Aperture Designed by Structural Synchronization of a Macrocycle and Supramolecular Synthon.
Precis Chem
May 2024
Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
To develop porous organic frameworks, precise control of the stacking manner of two-dimensional porous motifs and structural characterization of the resultant framework are important. From these points of view, porous molecular crystals formed through reversible intermolecular hydrogen bonds, such as hydrogen-bonded organic frameworks (HOFs), can provide deep insight because of their high crystallinity, affording single-crystalline X-ray diffraction analysis. In this study, we demonstrate that the stacking manner of hydrogen-bonded hexagonal network (HexNet) sheets can be controlled by synchronizing a homological triangular macrocyclic tecton and a hydrogen-bonded cyclic supramolecular synthon called the phenylene triangle.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!