It is shown that classical electrostatics quantitatively describes both the binding of the diatomic ligands XO (X = C, N, O) to the heme group in myoglobin and the dependence of their vibrational frequencies upon an external field, the vibrational Stark effect. The key is a proper treatment of induced dipoles. The results suggest that ligand binding occurs via an "electrostatic bond", a generalization of the standard ionic bond to include induction, and, more generally, that classical electrostatics can replace quantum mechanics for a considerable simplification of some complex problems.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/jp063971v | DOI Listing |
JACS Au
December 2024
Freie Universität Berlin, Physics Department, Experimental Molecular Biophysics, Arnimallee 14, 14195 Berlin, Germany.
Vibrational Stark effect (VSE) spectroscopy has become one of the most important experimental approaches to determine the strength of noncovalent, electrostatic interactions in chemistry and biology and to quantify their influence on structure and reactivity. Nitriles (C≡N) have been widely used as VSE probes, but their application has been complicated by an anomalous hydrogen bond (HB) blueshift which is not encompassed within the VSE framework. We present an empirical model describing the anomalous HB blueshift in terms of H-bonding geometry, i.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Saarland University, Coordination Chemistry, Campus C 4.1, 66123, Saarbrücken, GERMANY.
We report hitherto elusive side-on η2-bonded palladium(0) carbonyl (anthraquinone, benzaldehyde) and arene (benzene, hexa-fluorobenzene) palladium(0) complexes and present the catalytic hydrodefluorination of hexafluorobenzene by cyclohexene. The comparison with respective cyclohexene, pyridine and tetrahydrofuran complexes reveals that the experimental ligand binding strengths follow the order THF < C6H6 < C6F6 < cyclohexene < pyridine < benzaldehyde < anthraquinone. To understand this surprising order, the complexes' electronic structures were elucidated by nuclear magnetic resonance (NMR), single crystal X-Ray diffraction (sc-XRD), ultraviolet/visible (UV/Vis) electronic absorption, infrared (IR) vibrational, Pd L3-edge X-ray absorption (XAS), and X-ray photoelectron (XP) spectroscopic techniques, complemented by Density Functional Theory (DFT) calculations including energy decomposition (EDA-NOCV) and effective oxidation state (EOS) analyses.
View Article and Find Full Text PDFAerosp Med Hum Perform
November 2024
Introduction: The aviation occupational environment may expose a developing fetus to intermittent hypoxia, high gravitational force, toxic materials, loud noise, high frequency vibrations, and galactic cosmic radiation. These exposures in animal models are associated with adverse neonatal outcomes. We sought to investigate whether a maternal military aviation career was associated with adverse neonatal health outcomes.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune 411008, India.
Deep eutectic solvents have attracted considerable attention due to their unique properties and their potential to replace conventional solvents in diverse applications, such as catalysis, energy storage, and green chemistry. However, despite their broad use, the microscopic mechanisms governing solvation dynamics and the role of hydrogen bonding in deep eutectic solvents remain insufficiently understood. In this article, we present our contributions toward unravelling the micro heterogeneity within deep eutectic solvents by combining vibrational Stark spectroscopy and two-dimensional infrared spectroscopy with molecular dynamics simulations.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
Efficient light generation from triplet states of organic molecules has been a hot yet demanding topic in academia and the display industry. Herein, we propose a strategy for developing triplet emitter by creating heterostructures of organic chromophores and transition metal dichalcogenides (TMDs). These heterostructures emit microsecond phosphorescence at room temperature, while their organic chromophores intrinsically exhibit millisecond phosphorescence under vibration dissipation-free conditions.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!