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H Reisler - One of the best experts on this subject based on the ideXlab platform.
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communication determination of the Bond Dissociation Energy d0 of the water dimer h2o 2 by velocity map imaging
Journal of Chemical Physics, 2011Co-Authors: Blithe E Rochercasterline, Lee C Chng, Andrew K Mollner, H ReislerAbstract:The Bond Dissociation Energy (D0) of the water dimer is determined by using state-to-state vibrational preDissociation measurements following excitation of the bound OH stretch fundamental of the donor unit of the dimer. Velocity map imaging and resonance-enhanced multiphoton ionization (REMPI) are used to determine pair-correlated product velocity and translational Energy distributions. H2O fragments are detected in the ground vibrational (000) and the first excited bending (010) states by 2 + 1 REMPI via the C 1B1 (000) ← X 1A1 (000 and 010) transitions. The fragments’ velocity and center-of-mass translational Energy distributions are determined from images of selected rovibrational levels of H2O. An accurate value for D0 is obtained by fitting both the structure in the images and the maximum velocity of the fragments. This value, D0 = 1105 ± 10 cm−1 (13.2 ± 0.12 kJ/mol), is in excellent agreement with the recent theoretical value of D0 = 1103 ± 4 cm−1 (13.2 ± 0.05 kJ/mol) suggested as a benchmark by ...
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communication determination of the Bond Dissociation Energy d0 of the water dimer h2o 2 by velocity map imaging
Journal of Chemical Physics, 2011Co-Authors: Blithe E Rochercasterline, Lee C Chng, Andrew K Mollner, H ReislerAbstract:The Bond Dissociation Energy (D(0)) of the water dimer is determined by using state-to-state vibrational preDissociation measurements following excitation of the bound OH stretch fundamental of the donor unit of the dimer. Velocity map imaging and resonance-enhanced multiphoton ionization (REMPI) are used to determine pair-correlated product velocity and translational Energy distributions. H(2)O fragments are detected in the ground vibrational (000) and the first excited bending (010) states by 2 + 1 REMPI via the C (1)B(1) (000) ← X (1)A(1) (000 and 010) transitions. The fragments' velocity and center-of-mass translational Energy distributions are determined from images of selected rovibrational levels of H(2)O. An accurate value for D(0) is obtained by fitting both the structure in the images and the maximum velocity of the fragments. This value, D(0) = 1105 ± 10 cm(-1) (13.2 ± 0.12 kJ/mol), is in excellent agreement with the recent theoretical value of D(0) = 1103 ± 4 cm(-1) (13.2 ± 0.05 kJ∕mol) suggested as a benchmark by Shank et al. [J. Chem. Phys. 130, 144314 (2009)].
Esteban Vohringermartinez - One of the best experts on this subject based on the ideXlab platform.
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dft benchmark study of the o o Bond Dissociation Energy in peroxides validated with high level ab initio calculations
Theoretical Chemistry Accounts, 2020Co-Authors: Danilo J Carmona, Pablo Jaque, Esteban VohringermartinezAbstract:Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) 21131021 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1181914 1160197 Max-Planck-Society through a Max-Planck-Partner group
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a systematic electronic structure study of the o o Bond Dissociation Energy of hydrogen peroxide and the electron affinity of the hydroxyl radical
Theoretical Chemistry Accounts, 2018Co-Authors: Danilo J Carmona, Pablo Jaque, David Contreras, Oscar A Douglasgallardo, Stefan Vogtgeisse, Esteban VohringermartinezAbstract:Hydroxyl radical reduction and peroxide Bond breaking in hydrogen peroxide are reactions involved in various processes such as the Fenton reaction, which has applications as e.g. groundwater remediation. Here, we study these two reactions from a thermodynamical point of view through the Bond Dissociation Energy (BDE) of the O–O Bond in hydrogen peroxide and the electron affinity (EA) of the hydroxyl radical. High-level ab-initio calculations at the complete basis set (CBS) limit were carried out, and the performance of different DFT-based methods was addressed by following a specific classification on the basis of the Jacob’s ladder in combination with various Pople’s basis sets. The ab-initio calculations at the CBS limit are in agreement with experimental reference data and identify a significant contribution of the electron correlation Energy to the BDE and EA. The studied DFT-based methods were able to reproduce the ab-initio reference values, although no functional was particularly detected as the best for both reactions. The inclusion of certain percentage of Hartree–Fock (HF) exchange in DFT functionals leads in most cases to smaller BDE and EA values, which might be related to the poor description of the two reactions by the HF method. Considering the computational cost, DFT methods provide better BDE and EA values than HF methods with an accuracy comparable to the MP2 or CCSD level of theory. Additionally, the quality of the hydrogen peroxide, hydroxyl radical and hydroxyl anion structures obtained from these functionals was compared to experimental reference data. In general, Bond lengths were well reproduced and the errors in the angles were between one and two degrees with some systematic trend with respect to the basis set’s size. From our results we conclude that DFT methods present a computationally less expensive alternative to describe these two reactions that play a role in the Fenton reaction. The benchmark that is carried out in this study provides a systematic validation of various approximated $$E_{xc}[\rho ]$$ functionals combined with different basis sets, which could serve as a stepping-stone for future research on the Fenton reaction.
Jun Yeob Lee - One of the best experts on this subject based on the ideXlab platform.
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key host parameters for long lifetimes in phosphorescent organic light emitting diodes Bond Dissociation Energy in triplet excited state
Journal of Materials Chemistry C, 2020Co-Authors: Chang Yoon Yang, Sunwoo Kang, Hyein Jeong, Ho Jin Jang, Yoonkyoo Lee, Jun Yeob LeeAbstract:Key parameters of the host for long lifetimes in phosphorescent organic light-emitting diodes were investigated by synthesizing three isomeric hosts with a carbazolylcarbazole hole transport moiety and a benzonitrile electron transport moiety. The position of the CN unit was controlled as the ortho, meta and para position to the carbazolylcarbazole to study the relationship between material parameters and lifetime of the phosphorescent organic light-emitting diodes. It was revealed that the Bond Dissociation Energy in the triplet excited state is well-correlated with the device lifetime of the phosphorescent organic light-emitting diodes.
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Lifetime extension in green thermally activated delayed fluorescent organic light-emitting diodes by increasing excited state Bond Dissociation Energy
Journal of Industrial and Engineering Chemistry, 2019Co-Authors: Ho Jung Lee, Si Hyun Han, Wan Pyo Hong, Ok-keun Song, Jun Yeob LeeAbstract:Abstract A lifetime extending molecular design approach by increasing the Bond Dissociation Energy of the thermally activated delayed fluorescent (TADF) emitters was investigated. A TADF emitter with a molecular design having the donors in a planar manner, 4-(9H-carbazol-9-yl)-6-(9,9″-diphenyl-9H,9′H,9″H-[3,3′:6′,3″-tercarbazol]-9′-yl)isophthalonitrile (TCzIPN), was compared with state of the art green TADF emitter. The two emitters were green TADF emitters with similar peak wavelengths, but the TCzIPN exhibited three times longer lifetime than the current TADF emitter. Analysis of Bond Dissociation Energy of the TADF emitters revealed that the weak C N Bond of the TCzIPN was stabilized by small dihedral angle between donor and an aromatic linker. This was confirmed by exciton stability test of the emitters, and the C N Bond stabilization effect in triplet excited state was well correlated with the lifetime improvement of the TCzIPN devices.
Steven R Kass - One of the best experts on this subject based on the ideXlab platform.
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ferrocene acidity and c h Bond Dissociation Energy via experiment and theory
Journal of Physical Chemistry A, 2019Co-Authors: Brent Speetzen, Steven R KassAbstract:The gas-phase acidity of ferrocene (ΔH°acid(1) = 391.5 ± 1.3 kcal mol–1) and electron affinity of the ferrocenyl radical (EA(1r) = 1.74 ± 0.08 eV) were measured in a Fourier transform mass spectrom...
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phenylcyclopropane energetics and characterization of its conjugate base phenyl substituent effects and the c h Bond Dissociation Energy of cyclopropane
Journal of Organic Chemistry, 2016Co-Authors: Alireza Fattahi, Lev G Lis, Steven R KassAbstract:The α-C–H Bond Dissociation Energy (BDE) of phenylcyclopropane (1) was experimentally determined using Hess’ law. An equilibrium acidity determination of 1 afforded ΔH°acid = 389.1 ± 0.8 kcal mol–1, and isotopic labeling established that the α-position of the three-membered ring is the favored deprotonation site. Interestingly, the structure of the base proved to be a key factor in correctly determining the proper ionization site (i.e., secondary amide ions are needed, and primary ones and OH– lead to incorrect conclusions since they scramble the deuterium label). An experimental measurement of the electron affinity of 1-phenylcyclopropyl radical (EA = 17.5 ± 2.8 kcal mol–1) was combined with the ionization Energy of hydrogen (313.6 kcal mol–1) to afford BDE = 93.0 ± 2.9 kcal mol–1. This enabled the effect of the phenyl substituent to be evaluated and compared to other situations where it is attached to an sp3- or sp2-hybridized carbon center. M06-2X, CCSD(T), G4, and W1BD computations were also carried o...
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formation of a 1 bicyclo 1 1 1 pentyl anion and an experimental determination of the acidity and c h Bond Dissociation Energy of 3 tert butylbicyclo 1 1 1 pentane
Journal of the American Chemical Society, 2002Co-Authors: Dana R Reed, Steven R Kass, Kathleen R Mondanaro, William P DaileyAbstract:Decarboxylation of 1-bicyclo[1.1.1]pentanecarboxylate anion does not afford 1-bicyclo[1.1.1]pentyl anion as previously assumed. Instead, a ring-opening isomerization which ultimately leads to 1,4-pentadien-2-yl anion takes place. A 1-bicyclo[1.1.1]pentyl anion was prepared nevertheless via the fluoride-induced desilylation of 1-tert-butyl-3-(trimethylsilyl)bicyclo[1.1.1]pentane. The electron affinity of 3-tert-butyl-1-bicyclo[1.1.1]pentyl radical (14.8 ± 3.2 kcal/mol) was measured by bracketing, and the acidity of 1-tert-butylbicyclo[1.1.1]pentane (408.5 ± 0.9) was determined by the DePuy kinetic method. These values are well-reproduced by G2 and G3 calculations and can be combined in a thermodynamic cycle to provide a bridgehead C−H Bond Dissociation Energy (BDE) of 109.7 ± 3.3 kcal/mol for 1-tert-butylbicyclo[1.1.1]pentane. This Bond Energy is the strongest tertiary C−H Bond to be measured, is much larger than the corresponding Bond in isobutane (96.5 ± 0.4 kcal/mol), and is more typical of an alkene or...
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dodecahedryl anion formation and an experimental determination of the acidity and c h Bond Dissociation Energy of dodecahedrane
Journal of the American Chemical Society, 2000Co-Authors: Katherine M Broadus, Thomas Osswald, Steven R Kass, Horst PrinzbachAbstract:Dodecahedryl anion (1a) was generated in a Fourier transform mass spectrometer by deprotonation of dodecahedrane (1). Examination of the acid and base behavior of 1 and 1a, respectively, enabled the acidity of 1 to be determined (ΔH°acid = 402 ± 2 kcal/mol). Good agreement is found with the 298 K computed MP2/6-31+G(d)//HF/6-31+G(d) value of 405.1 kcal/mol. In a similar manner, the electron affinity of dodecahedryl radical was measured (EA = 4 ± 2 kcal/mol). These results were combined in a thermodynamic cycle to afford the C−H Bond Dissociation Energy of dodecahedrane (BDE = 92 ± 3 kcal/mol), which is reasonably well reproduced (96.7 kcal/mol) at the MP2//HF level but leads to the suggestion that the reported heat of hydrogenation of dodecahedrene is in error. The DePuy kinetic method for measuring the acidity of 1 also was explored. It was found that this approach works well with triphenylsilyldodecahedrane but gives poor results with triethylsilyldodecahedrane. This latter failure is attributed to ster...
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cubyl anion formation and an experimental determination of the acidity and c h Bond Dissociation Energy of cubane
Journal of the American Chemical Society, 1997Co-Authors: Michael Hare, Todd Emrick, P E Eaton, Steven R KassAbstract:Cubane (1) and its derivatives have been the subject of numerous investigations ever since Eaton’s synthesis of the parent compound in 1964.1,2 Kinetic measurements indicate that 1 is an unusually acidic alkane3 and that its carbon-hydrogen Bond Dissociation Energy (BDE) is considerably greater than that for a typical tertiary C-H Bond.4 The thermodynamic values for these quantities, however, are unknown. Cubane’s acidity along with the electron affinity of cubyl radical could be used to derive the homolytic C-H BDE via a thermodynamic cycle (eq 1).
Blithe E Rochercasterline - One of the best experts on this subject based on the ideXlab platform.
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communication determination of the Bond Dissociation Energy d0 of the water dimer h2o 2 by velocity map imaging
Journal of Chemical Physics, 2011Co-Authors: Blithe E Rochercasterline, Lee C Chng, Andrew K Mollner, H ReislerAbstract:The Bond Dissociation Energy (D0) of the water dimer is determined by using state-to-state vibrational preDissociation measurements following excitation of the bound OH stretch fundamental of the donor unit of the dimer. Velocity map imaging and resonance-enhanced multiphoton ionization (REMPI) are used to determine pair-correlated product velocity and translational Energy distributions. H2O fragments are detected in the ground vibrational (000) and the first excited bending (010) states by 2 + 1 REMPI via the C 1B1 (000) ← X 1A1 (000 and 010) transitions. The fragments’ velocity and center-of-mass translational Energy distributions are determined from images of selected rovibrational levels of H2O. An accurate value for D0 is obtained by fitting both the structure in the images and the maximum velocity of the fragments. This value, D0 = 1105 ± 10 cm−1 (13.2 ± 0.12 kJ/mol), is in excellent agreement with the recent theoretical value of D0 = 1103 ± 4 cm−1 (13.2 ± 0.05 kJ/mol) suggested as a benchmark by ...
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communication determination of the Bond Dissociation Energy d0 of the water dimer h2o 2 by velocity map imaging
Journal of Chemical Physics, 2011Co-Authors: Blithe E Rochercasterline, Lee C Chng, Andrew K Mollner, H ReislerAbstract:The Bond Dissociation Energy (D(0)) of the water dimer is determined by using state-to-state vibrational preDissociation measurements following excitation of the bound OH stretch fundamental of the donor unit of the dimer. Velocity map imaging and resonance-enhanced multiphoton ionization (REMPI) are used to determine pair-correlated product velocity and translational Energy distributions. H(2)O fragments are detected in the ground vibrational (000) and the first excited bending (010) states by 2 + 1 REMPI via the C (1)B(1) (000) ← X (1)A(1) (000 and 010) transitions. The fragments' velocity and center-of-mass translational Energy distributions are determined from images of selected rovibrational levels of H(2)O. An accurate value for D(0) is obtained by fitting both the structure in the images and the maximum velocity of the fragments. This value, D(0) = 1105 ± 10 cm(-1) (13.2 ± 0.12 kJ/mol), is in excellent agreement with the recent theoretical value of D(0) = 1103 ± 4 cm(-1) (13.2 ± 0.05 kJ∕mol) suggested as a benchmark by Shank et al. [J. Chem. Phys. 130, 144314 (2009)].