Relationship between Hydrogen-Bonding Motifs and the 1b1 Splitting in the X-ray Emission Spectrum of Liquid Water

2021 ◽  
Vol 12 (16) ◽  
pp. 3996-4002
Author(s):  
Vinícius Wilian D. Cruzeiro ◽  
Andrew Wildman ◽  
Xiaosong Li ◽  
Francesco Paesani
2020 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Andrew Wildman ◽  
Xiasong Li ◽  
Francesco Paesani

The split of the 1<i>b</i><sub>1</sub> peak observed in the X-ray emission (XE) spectrum of liquid water has been the focus of intense research over the last two decades. Although several hypotheses have been proposed to explain the origin of the 1<i>b</i><sub>1</sub> splitting, a general consensus has not yet been reached. In this study, we introduce a novel theoretical/computational approach which, combining path-integral molecular dynamics (PIMD) simulations carried out with the MB-pol potential energy function and time-dependent density functional theory (TD-DFT) calculations, correctly predicts the split of the 1<i>b</i><sub>1</sub> peak in liquid water and not in crystalline ice. A systematic analysis in terms of the underlying local structure of liquid water at ambient conditions indicates that several different hydrogen-bonding motifs contribute to the overall XE lineshape in the energy range corresponding to emissions from the 1<i>b</i><sub>1</sub> orbitals, which suggests that it is not possible to unambiguously attribute the split of the 1<i>b</i><sub>1</sub> peak to only two specific structural arrangements of the underlying hydrogen-bonding network.


2002 ◽  
Vol 89 (13) ◽  
Author(s):  
J.-H. Guo ◽  
Y. Luo ◽  
A. Augustsson ◽  
J.-E. Rubensson ◽  
C. Såthe ◽  
...  

2020 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Andrew Wildman ◽  
Xiasong Li ◽  
Francesco Paesani

The split of the 1<i>b</i><sub>1</sub> peak observed in the X-ray emission (XE) spectrum of liquid water has been the focus of intense research over the last two decades. Although several hypotheses have been proposed to explain the origin of the 1<i>b</i><sub>1</sub> splitting, a general consensus has not yet been reached. In this study, we introduce a novel theoretical/computational approach which, combining path-integral molecular dynamics (PIMD) simulations carried out with the MB-pol potential energy function and time-dependent density functional theory (TD-DFT) calculations, correctly predicts the split of the 1<i>b</i><sub>1</sub> peak in liquid water and not in crystalline ice. A systematic analysis in terms of the underlying local structure of liquid water at ambient conditions indicates that several different hydrogen-bonding motifs contribute to the overall XE lineshape in the energy range corresponding to emissions from the 1<i>b</i><sub>1</sub> orbitals, which suggests that it is not possible to unambiguously attribute the split of the 1<i>b</i><sub>1</sub> peak to only two specific structural arrangements of the underlying hydrogen-bonding network.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4097
Author(s):  
Wooyong Seong ◽  
Hyungwoo Hahm ◽  
Seyong Kim ◽  
Jongwoo Park ◽  
Khalil A. Abboud ◽  
...  

Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO2. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) of the bis-urea salen Al catalyst is three times higher than that of a μ-oxo-bridged catalyst, and 13 times higher than that of a monomeric salen aluminum catalyst. The bimetallic reaction pathway is suggested based on urea additive studies and kinetic studies. Additionally, the X-ray crystal structure of a bis-urea salen Ni complex supports the self-assembly of the bis-urea salen metal complex through hydrogen bonding.


Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.


2020 ◽  
Vol 7 (21) ◽  
pp. 4197-4221 ◽  
Author(s):  
Francisco Colmenero ◽  
Jakub Plášil ◽  
Jiří Sejkora

The structure, hydrogen bonding, X-ray diffraction pattern and mechanical properties of six important uranyl carbonate minerals, roubaultite, fontanite, sharpite, widenmannite, grimselite and čejkaite, are determined using first principles methods.


2014 ◽  
Vol 70 (a1) ◽  
pp. C534-C534
Author(s):  
Nasreddine Ghouari ◽  
Nourreedine Benali-Cherif

The theme of this work is part of the study of intermolecular interactions that hold the crystal structures of hybrid compounds based sulphuric acid, nitric acid, Melamine, Diethylamine, L-(+) - glutamic acid, DL-2-amino butyric acid. The aim of this work is to enlarge our laboratory researches [1-3] and methods in synthesis of new hybrid compounds consisting in organic cation(s) and mineral anion(s). We have obtained single crystals of a few samples after several trials and we plan to synthesize and characterize these crystals by X-ray diffraction, FTIR and Raman. The crystals structures allow us to study the 3D network hydrogen bonding, electron density and collect several other informations useful in FTIR and Raman studies of these hybrid compounds.


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