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Main Title: Microhydration of protonated biomolecular building blocks: protonated pyrimidine
Author(s): Chatterjee, Kuntal
Dopfer, Otto
Type: Article
Language Code: en
Abstract: Protonation and hydration of biomolecules govern their structure, conformation, and function. Herein, we explore the microhydration structure in mass-selected protonated pyrimidine–water clusters (H+Pym–Wn, n = 1–4) by a combination of infrared photodissociation spectroscopy (IRPD) between 2450 and 3900 cm−1 and density functional theory (DFT) calculations at the dispersion-corrected B3LYP-D3/aug-cc-pVTZ level. We further present the IR spectrum of H+Pym–N2 to evaluate the effect of solvent polarity on the intrinsic molecular parameters of H+Pym. Our combined spectroscopic and computational approach unequivocally shows that protonation of Pym occurs at one of the two equivalent basic ring N atoms and that the ligands in H+Pym–L (L = N2 or W) preferentially form linear H-bonds to the resulting acidic NH group. Successive addition of water ligands results in the formation of a H-bonded solvent network which increasingly weakens the NH group. Despite substantial activation of the N–H bond upon microhydration, no intracluster proton transfer occurs up to n = 4 because of the balance of relative proton affinities of Pym and Wn and the involved solvation energies. Comparison to neutral Pym–Wn clusters reveals the drastic effects of protonation on microhydration with respect to both structure and interaction strength.
Issue Date: 27-May-2020
Date Available: 26-Jun-2020
DDC Class: 540 Chemie und zugeordnete Wissenschaften
Subject(s): hydration
noncovalent interaction
Sponsor/Funder: TU Berlin, Open-Access-Mittel - 2020
Journal Title: Physical Chemistry Chemical Physics
Publisher: Royal Society of Chemistry (RSC)
Publisher Place: Cambridge
Volume: 22
Publisher DOI: 10.1039/D0CP02110E
Page Start: 13092
Page End: 13107
EISSN: 1463-9084
ISSN: 1463-9076
Appears in Collections:FG Lasermolekülspektroskopie und Umweltphysik » Publications

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