Search results for "Arama"

showing 3 items of 903 documents

Spin Crossover and Long-Lived Excited States in a Reduced Molecular Ruby.

2020

Abstract The chromium(III) complex [CrIII(ddpd)2]3+ (molecular ruby; ddpd=N,N′‐dimethyl‐N,N′‐dipyridine‐2‐yl‐pyridine‐2,6‐diamine) is reduced to the genuine chromium(II) complex [CrII(ddpd)2]2+ with d4 electron configuration. This reduced molecular ruby represents one of the very few chromium(II) complexes showing spin crossover (SCO). The reversible SCO is gradual with T 1/2 around room temperature. The low‐spin and high‐spin chromium(II) isomers exhibit distinct spectroscopic and structural properties (UV/Vis/NIR, IR, EPR spectroscopies, single‐crystal XRD). Excitation of [CrII(ddpd)2]2+ with UV light at 20 and 290 K generates electronically excited states with microsecond lifetimes. This…

step-scan IR spectroscopychemistry.chemical_element010402 general chemistryPhotochemistry01 natural sciencesCatalysislaw.inventionChromiumSpin crossoverlawSpin CrossoverElectron paramagnetic resonanceexcited states010405 organic chemistryChemistryCommunicationOrganic ChemistryGeneral ChemistryCommunications0104 chemical sciencesMicrosecondExcited stateElectron configurationchromiummagnetic propertiesExcitationChemistry (Weinheim an der Bergstrasse, Germany)
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Photoluminescence and Electron Spin Resonance of Silicon Dioxide Crystal with Rutile Structure (Stishovite)

2018

This work was supported by ERANET MYND. Also, financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2017/2 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. The authors express our gratitude to R.I. Mashkovtsev for help in ESR signal interpretation. The authors are appreciative to T.I. Dyuzheva, L.M. Lityagina, N.A. Bendeliani for stishovite single crystals and to K. Hubner and H.-J. Fitting for stishovite powder of Barringer Meteor Crater.

stishovitesMaterials sciencePhotoluminescenceSilicon dioxideFOS: Physical sciences02 engineering and technology01 natural sciencesMolecular physicslaw.inventionCrystalchemistry.chemical_compoundlaw0103 physical sciences:NATURAL SCIENCES:Physics [Research Subject Categories]luminescenceMaterials Chemistryelectron spin resonancesElectrical and Electronic Engineering010306 general physicsElectron paramagnetic resonancedefectsStishoviteCondensed Matter - Materials Sciencedense silicon dioxidesMaterials Science (cond-mat.mtrl-sci)Surfaces and Interfaces021001 nanoscience & nanotechnologyCondensed Matter PhysicsSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialschemistryExcited state0210 nano-technologyLuminescenceSingle crystal
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An experimental and theoretical study of a heptacoordinated tungsten(VI) complex of a noninnocent phenylenediamine bis(phenolate) ligand

2018

Abstract [W(N2O2)(HN2O2)] (H4N2O2 = N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)-1,2-phenylenediamine) with a noninnocent ligand was formed by reaction of the alkoxide precursor [W(eg)3] (eg = the 1,2-ethanediolate dianion) with two equivalents of ligand. The phenol groups on one of the ligands are completely deprotonated and the ligand coordinates in a tetradentate fashion, whereas the other ligand is tridentate with one phenol having an intact OH group. The molecular structure, magnetic measurements, EPR spectroscopy, and density functional theory calculations indicate that the complex is a stable radical with the odd electron situated on the tridentate amidophenoxide ligand. The formal ox…

tungstenDFT calculations010402 general chemistry01 natural scienceslaw.inventionInorganic Chemistrychemistry.chemical_compoundDeprotonationlawOxidation stateMaterials ChemistryMoleculePhysical and Theoretical ChemistryElectron paramagnetic resonanceta116amidophenoxide radical010405 organic chemistryLigandkompleksiyhdisteetvolframielectronic structure0104 chemical sciencesCrystallographyoxidation statesUnpaired electronchemistryAlkoxidenoninnocent ligandDensity functional theoryInorganic Chemistry Communications
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