A theoretical treatment of the two-dimensional exchange nuclear quadrupole resonance pulse sequence is presented and applied to the quantitative study of exchange processes in molecular crystals. The theory is successfully tested for the exchange spectra of hindered trichloromethyl groups of p-chlorobenzotrichloride, where the conventional approach without taking into account the off-resonance phenomena has failed. The mixing dynamics by exchange and the expected diagonal- and cross-peak intensities as a function of the mixing time have been derived. It is shown that the off-resonance effects are of crucial importance for the quantitative description of the exchange spectra.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/mrc.2703 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Controlling pseudopolymorphism robust and repetitive solvent-containing supramolecular interactions in urea-based isostructural coordination polymers.
Dalton Trans
January 2025
Department of Inorganic Chemistry, Shahid Beheshti University, 1983969411, Tehran, Iran.
In a systematic study, six pseudopolymorphic coordination polymers containing the ditopic 1,3-di(pyridin-4-yl)urea ligand (4bpu) constructed with d metal cations, possessing the formula {[M(4bpu)I]S} [(M = Zn, Cd and Hg), (S = MeOH or EtOH)], namely Zn-MeOH, Zn-EtOH, Cd-MeOH, Cd-EtOH, Hg- and Hg-EtOH were obtained. The title compounds were characterized by single-crystal X-ray diffraction analysis (SC-XRD), elemental analysis (CHN), FT-IR spectroscopy, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). The diffraction studies show that these compounds are isostructural 1D zig-zag chain coordination polymers which is also confirmed using XPac 2.
View Article and Find Full Text PDFExpansion counteraction effect assisted vanadate with rich oxygen vacancies as a high cycling stability cathode for aqueous zinc-ion batteries.
Phys Chem Chem Phys
January 2025
State Key Laboratory of Materials-Oriented Chemical Engineering and School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
In this study, a novel tunnel structure vanadate NaVO (NaVO) cathode for aqueous zinc ion batteries (AZIBs) is facilely fabricated by thermal decomposition of polyoxovanadate containing NH ions. The NaVO cathode is characterized by abundant oxygen vacancies and nanometer dimensions. These attributes can offer extra reaction sites and suppress structural collapse during circulation.
View Article and Find Full Text PDFDecision Trees for the Recognition of Metal-Centered Chirality in Coordination Complexes.
J Comput Chem
January 2025
Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
While established guidelines exist for chirality in tetrahedral molecules, there is a notable absence of clear rules for recognizing metal-centered chirality in higher-coordination complexes. We develop decision trees to assess the likelihood of chirality-at-metal in coordination complexes with coordination numbers 4-9 with mono and bidentate ligands. Using binary decision rules based on shape, ligand type, and quantity, the trees classify complexes as chiral or achiral.
View Article and Find Full Text PDFEnhanced Homogeneous Photocatalytic Hydrogen Evolution in a Binuclear Bio-inspired Ni-Ni Complex Bearing Phenanthroline and Sulfidophenolate Ligands.
Chemistry
January 2025
National & Kapodistrian University of Athens, Chemistry, Panepistimiopolis, Zografou, 15771, Athens, GREECE.
The prominence of binuclear catalysts underlines the need for the design and development of diverse bifunctional ligand frameworks that exhibit tunable electronic and structural properties. Such strategies enable metal-metal and ligand-metal cooperation towards catalytic applications, improve catalytic activity, and are essential for advancing multi-electron transfers for catalytic application. Hereby, we present the synthesis, crystal structure, and photocatalytic properties of a binuclear Ni(II) complex, [Ni2(1,10-phenanthroline)2(2-sulfidophenolate)2] (1), which crystallizes in the centrosymmetric triclinic system (P-1) showing extensive intra- and inter- non-coordinated interactions.
View Article and Find Full Text PDFMolecular Engineering of Amino Acid Crystals with Enhanced Piezoelectric Performance for Biodegradable Sensors.
Angew Chem Int Ed Engl
January 2025
Nanjing University, Department of Physics, 22 Hankou Road, 210093, Nanjing, CHINA.
Amino acid crystals have emerged as promising piezoelectric materials for biodegradable and biocompatible sensors; however, their relatively low piezoelectric coefficients constrain practical applications. Here, we introduce a fluoro-substitution strategy to overcome this limitation and enhance the piezoelectric performance of amino acid crystals. Specifically, we substituted hydrogen atoms on the aromatic rings of L-tryptophan, L-phenylalanine, and N-Cbz-L-phenylalanine with fluorine, resulting in significantly elevated piezoelectric coefficients.
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!