A5078995834- Various Chemistry Research Topics
- History and advancements in chemistry
- Chemistry and Chemical Engineering
- Advanced Chemical Physics Studies
- Mass Spectrometry Techniques and Applications
- Chemical Reaction Mechanisms
- Chemical Reactions and Mechanisms
- Chemical Reactions and Isotopes
- Molecular Spectroscopy and Structure
- Analytical Chemistry and Chromatography
- Molecular spectroscopy and chirality
- Spectroscopy and Quantum Chemical Studies
- Inorganic and Organometallic Chemistry
- Catalysis and Oxidation Reactions
- Atmospheric chemistry and aerosols
- Fluorine in Organic Chemistry
- Inorganic Fluorides and Related Compounds
- Crystallography and molecular interactions
- Molecular Junctions and Nanostructures
- Radioactive element chemistry and processing
- Free Radicals and Antioxidants
- Chemical Thermodynamics and Molecular Structure
- Photochemistry and Electron Transfer Studies
- Carbon dioxide utilization in catalysis
- CO2 Reduction Techniques and Catalysts
University of Oslo
2015-2024
Kjemi (Norway)
2007-2023
657 Oslo
2014-2018
Blindeninstitutsstiftung
2017
University of Tartu
2015
Kyushu University
2015
Leipzig University
2014
Kirkelig Pedagogisk Senter
2008-2014
Norges Blindeforbund
2014
Laboratoire de Chimie Organique
2012
Quantum chemical calculations (OPBE/6-311++G(d,p)) have been performed to uncover the electronic factors that govern reactivity in prototypical SNAr reaction. It was found intrinsic nucleophilicity—expressed as critical energy (the required for forming Meisenheimer structure Ph(X)2−) identity substitution reaction X− + PhX → (Ph = phenyl)—shows following approximate trend: NH2− ≈ OH− F− ≫ PH2− SH− Cl− > AsH2− SeH− Br−. The periodic trends are discussed terms of molecular properties (proton...
Methyl formate, HCOOCH3, is a well-known interstellar molecule prominent in the spectra of hot molecular cores. The current view its formation that it occurs gas phase from precursor methanol, which synthesized on surfaces grain mantles during previous colder era and evaporates while temperatures increase process high-mass star formation. specific reaction sequence thought to form methyl ion-molecule between protonated methanol formaldehyde followed by dissociative recombination ion...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDynamics of the reaction CH2OH+ .fwdarw. CHO+ + H2. Translational energy release from ab initio trajectory calculationsEinar Uggerud and Trygve HelgakerCite this: J. Am. Chem. Soc. 1992, 114, 11, 4265–4268Publication Date (Print):May 1, 1992Publication History Published online1 May 2002Published inissue 1 1992https://doi.org/10.1021/ja00037a033RIGHTS & PERMISSIONSArticle Views363Altmetric-Citations132LEARN ABOUT THESE METRICSArticle Views are...
It is experimentally challenging to directly obtain structural information of the transition state (TS), high-energy bottleneck en route from reactants products, for solution-phase reactions. Here, we use single-molecule experiments as well high-level quantum chemical calculations probe TS disulfide bond reduction, a bimolecular nucleophilic substitution (SN2) reaction. We an atomic force microscope in force-clamp mode apply mechanical forces protein and force-dependent rate constants...
A magnesium complex incorporating a novel metal-CO2 binding motif is spectroscopically identified. Here we show with the help of infrared photodissociation spectroscopy that exists solely in [ClMg(η(2) -O2 C)](-) form. This bidentate double oxygen coordination has previously not been observed neutral nor charged unimetallic complexes. The antisymmetric CO2 stretching mode found at 1128 cm(-1) , which considerably redshifted from corresponding bare 2349 suggesting moiety considerable negative...
Abstract This Glossary contains definitions, explanatory notes, and sources for terms used in physical organic chemistry. Its aim is to provide guidance on the terminology of chemistry, with a view achieving consensus meaning applicability useful abandonment unsatisfactory ones. Owing substantial progress field, this 2021 revision much expanded relative previous edition, it includes from cognate fields.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory of collisional activation macromolecules. Impulsive collisions organic ionsEinar Uggerud and Peter J. DerrickCite this: Phys. Chem. 1991, 95, 3, 1430–1436Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://doi.org/10.1021/j100156a073RIGHTS & PERMISSIONSArticle Views235Altmetric-Citations91LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum full text...
Myths of steric hindrance: In contrast with current opinion, energy decomposition analysis shows that the presence bulky substituents at carbon leads to release repulsion in transition state shown graphic. It is rather weakening electrostatic attraction, and particular loss attractive orbital interactions, are responsible for activation barrier. Quantum chemical calculations S(N)2 reactions H(3)EX/X(-) systems, which E=C or Si X=F Cl, reported. case system we also report on bulkier species...
The relative reactivity of any given neutral platinum cluster falls in-between that the corresponding anion and cation.
The mechanochemistry of the disulfide bridge--that is, influence an externally applied force on reactivity sulfur-sulfur bond--is investigated by unrestricted Kohn-Sham theory. Specifically, we apply COGEF (constrained geometry simulates external force) approach to characterize bond in three different chemical environments: dimethyl disulfide, cystine, and a 102-atom model I27 domain titin protein. Furthermore, mechanism thiol-disulfide reduction reaction under effect is considering...
A good fix: The structure and chemical reactivity of a reduced form CO2 bonded to magnesium, XMg(η2-O2C)−, is reported. Upon reaction with water it loses CO, while adds CH3 upon alkyl halides, thereby signifying nucleophilicity the carbon atom in XMg(η2-O2C)− SN2 reactions. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by authors. Please note: publisher...
The potential energy profiles of 18 identity S(N)2 reactions have been estimated by using G2-type quantum-chemical calculations. are: X- + CH3-X --> X-CH3 and XH CH3-XH+ +HX-CH3 (X = NH2, OH, F, PH2, SH, Cl, AsH2, SeH, Br). Despite the charge difference, barrier heights geometrical requirements upon going from reactant to transition structure are surprisingly similar for XH. decrease on left right in periodic table, increasing ionization (of XH) is correlated with decreasing barrier....
Rates for the dihydrogen elimination of methane, ethane, and propane with cationic platinum clusters, Pt(n) (+) (1<or=n<or=21), were measured under binary collision conditions in a Fourier transform ion cyclotron resonance mass spectrometer (FTICR). The reaction rate given cluster, Ptn +, follows trend k(CH4)<k (C2H6)<k(C3H8). Methane is particular sense that reactivity highly variable; some clusters (n=1-3, 5-9, 11, 12, 15) are very reactive towards while all other react low efficiency or...
Experimental mass abundance spectra are used to extract evaporative activation energies (dissociation energies) for protonated water clusters, (H2O)NH+, and deprotonated (H2O)NOH−, in the size range up hundred molecules. The inversion is achieved by application of shell correction method adapted from nuclear physics spectra. well known anomaly clusters which occurs N=20–22 found have characteristic behavior a closing, whereas other apparent magic numbers only prominent peaks because...
The intrinsic electronic factors that determine reactivity in prototypical identity nucleophilic vinylic substitution reactions, X– + ViX → XVi (Vi = vinyl), have been studied by performing quantum chemical calculations (OPBE/6-311++G(d,p)). Of the two limiting reaction types envisaged—the SNVπ and SNVσ mechanisms—the former is preferred for most combinations of nucleophiles substrates, except combination unactivated substrates poor nucleophiles, as seen much reactions Cl– CH2CHCl Br–...
Density functional theory calculations show that both ring opening and chain dissociation of polymeric triazoles are facilitated by mechanical stretching the molecules—the latter more than former. Experimentally observed upon sonication can therefore not be explained a mechanism alone.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUnimolecular Chemistry of Protonated Formamide. Mass Spectrometry and ab Initio Quantum Chemical CalculationsHung-Yu Lin, Douglas P. Ridge, Einar Uggerud, Tore VulpiusCite this: J. Am. Chem. Soc. 1994, 116, 7, 2996–3004Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 1994https://pubs.acs.org/doi/10.1021/ja00086a032https://doi.org/10.1021/ja00086a032research-articleACS PublicationsRequest...
Invoking a number of theoretical levels ranging from HF/STO-3G to CCSD(T)/aug-cc-pVQZ, we have made detailed survey six potential energy surfaces (NH 4 + , NH • [CH 3 CONHCH ]H [HCONHCH 2 CONH and ). In conjunction with this, ab inito direct dynamics calculations been conducted, tracing out several hundred reaction trajectories reveal details the electron-capture dissociation mechanism. The model suggest possibility bimodal pattern where some radicals, formed upon recombination, dissociate...
The rate coefficients for the dehydrogenation of ethane, propane, and isobutane with cationic rhodium atoms Rh+ clusters n up to 30 were measured under single-collision conditions in a Fourier-transform ion cyclotron resonance mass spectrometer. reaction rates are cluster size dependent parallel all three alkanes. While reactions proceed close theoretical collision large number clusters, characteristic minima observed (5/6/9/19/28). degree varies maxima 10< or =n< =15 alkanes n=3 2-4 cases...
The performance of some commonly used quantum-chemical methods in accurately and reliably describing the influence applying an external mechanical force has been investigated for a set small molecules. By coupled-cluster CCSD(T) theory extended basis as benchmark, all tested provide good qualitative description physical process, although quantitative agreement varies considerably. Hartree–Fock (HF) overestimates both values bond-breaking point rupture force, typically by 20–30%. same applies...
The activation of CO<sub>2</sub> by chloride-tagged first-row transition metal anions [ClM]<sup>−</sup> (M = Sc–Zn), was examined mass spectrometry, quantum chemical calculations, and statistical analysis.