Binding energies of chromium cations with fluorobenzenes from radiative association kinetics

Ryzhov, Victor; Yang, Chia‐Ning; Klippenstein, Stephen J.; Dunbar, Robert C.

doi:10.1016/s1387-3806(98)14271-9

Cited by 22 publications

(36 citation statements)

References 18 publications

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“…A mixed valence basis set was used with 6-31g(d) on hydrogen, 6-31ϩg(d) on carbon, and 6-311ϩg(d) on chlorine and on the metal. As found in other similar studies of our group [12][13][14], this basis set is sufficient to reduce basis set superposition errors (BSSE) near or below 1 kcal mol Ϫ1 , which is unimportant compared with other uncertainties.…”

Section: Methodssupporting

confidence: 53%

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Reactivity and binding energies of transition metal halide ions with benzene

Gapeev

Dunbar

2002

J. Am. Soc. Mass Spectrom.

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We have generated novel halogen-ligated transition metal ions MX n ϩ (M ϭ Sc, Ti, V, and Fe, X ϭ Cl, Br and I, n ϭ 1 Ϫ 3). We have explored their reactions with benzene, a typical aromatic hydrocarbon. Attachment of one benzene molecule is usually rapid, whereas attachment of a second benzene molecule is generally much slower. The kinetics were analyzed to estimate binding energies, modeling the attachment reaction as a radiative association process. In all cases the Standard Hydrocarbon semiquantitative estimation approach was employed, and in some cases the more accurate variational transition state (VTST) kinetic modeling approach was also applied. Density functional (DFT) quantum calculations were also performed to give computed binding energies for some of the complexes. Taking previously determined binding energies for halogen-ligated alkaline-earth ions as benchmarks, it is concluded that binding of the first benzene molecule to the transition-metal species is strongly enhanced by specific chemical interactions, while binding of the second benzene molecule is more nearly electrostatic. The binding energies are not strongly dependent on the identity of the transition metal ion, and the metal-ion dependences can be rationalized in terms of valence-orbital occupations of the metals. The binding energies are nearly independent of the identity of the halogen ligands. . Cation-pi interactions in biological systems involve metal ions in their stable oxidation state (ϩ1 for alkali metals, ϩ2 for alkaline-earth metals, usually ϩ2 and ϩ3 for the transition metals). This means that gas-phase studies of singly charged systems have direct biological relevance for the alkali ions, but have less clear relevance for most other metal ions. However, using double or triply charged gas-phase metal ions in the absence of solvent leveling introduces large electrostatic interactions that are likely to swamp the chemical interactions one would like to study in the gas phase. A way to resolve this dilemma is to attach ligands to the singly charged metal, thereby raising its oxidation state to its biologically relevant value. Halogen ligands seem to be the best choice because they do not migrate from the metal center nor do they promote ion-molecule reactions.Our previous work in pursuit of this strategy [2] investigated the reactions and binding energies of singly charged, halogenated alkaline-earth metal ions with benzene and mesitylene. The binding energies of the halogen-metal ions to benzene were greatly enhanced relative to the bare metal ions, although still much smaller than the predicted binding energies of bare doubly charged ions. It appeared that the binding in these cases was well described as electrostatic in nature, and that the MX ϩ ions showed behavior intermediate between singly-charged and doubly-charged character. A useful description was that the halogenated metal ions behaved toward the benzene ligand with an effective charge between ϩ1 and ϩ2. For MgCl ϩ a simple classical-electrostatic analysis suggested an...

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Section: Methodssupporting

confidence: 53%

“…The rough lower limit imposed by the collisionally saturated V ϩ result is uninformative. As one other example, the binding energy of Cr ϩ derived in earlier work by VTST modeling was higher than accepted values [13]. Thus this approach does not seem to be quantitatively reliable for these transition-metal atomic-ion/benzene systems.…”

Section: Discussionmentioning

confidence: 70%

Reactivity and binding energies of transition metal halide ions with benzene

Gapeev

Dunbar

2002

J. Am. Soc. Mass Spectrom.

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“…Recent work has combined such quantum-chemical molecular information with transitionstate theory kinetic methods to calculate accurate and reliable radiative association (RA) reaction rate coefficients. [20][21][22][32][33][34][35][36] …”

Section: Introductionmentioning

confidence: 99%

Radiative Association Reactions of Na⁺, Mg⁺, and Al⁺ with Abundant Interstellar Molecules. Variational Transition State Theory Calculations

Petrie

Dunbar

2000

J. Phys. Chem. A

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Ab initio calculations using G2 theory and other methods have been performed for the collision complexes of the metal ions Na + , Mg + , and Al + with the molecules H 2 , CO, N 2 , NH 3 , H 2 O, HCN, HNC, C 2 H 2 , C 2 H 4 , c-C 3 H 2 , H 2 CCC, H 2 CCCC, and HCCCN. Binding energies, vibrational frequencies, and infrared intensities obtained from these calculations have been used to perform variational transition state theory (VTST) calculations for the corresponding radiative association reactions at temperatures pertinent to dense interstellar clouds and the outer regions of circumstellar envelopes. The calculated rate coefficients for radiative association reactions with H 2 and with the other smaller molecules of this group are slow compared with the chemical evolutionary time scale of cold interstellar clouds. For the largest and most strongly bound complexes considered, the rate of depletion of M + by this mechanism becomes competitive with recombination of M + with free electrons. Predicted rates for association in several systems at high pressure are in order-of-magnitude agreement with experiments, except for Mg + /H 2 O, which is predicted to be substantially faster than a recent experimental upper limit.

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“…Addition of isobutene (1 atm, 298 K) to in situ prepared 5b in F 5 C 6 Hs olutionr esulted in the appearance of an ew resonance in the 31 P{ 1 H} spectrum at d 94. 8 [15] ]. Signals for 5b were completely absent from the 1 H, 31 P{ 1 H} and 19 7), in moderate (50 %) yield, suitablef or characterization by single-crystal X-ray diffraction.…”

Section: Relativereactivities Of Cationic H-bound Pfb Rh Complexesmentioning

confidence: 99%

Synthesis of Highly Fluorinated Arene Complexes of [Rh(Chelating Phosphine)]⁺ Cations, and their use in Synthesis and Catalysis

McKay

Barwick-Silk

Savage

et al. 2020

Chemistry A European J

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The synthesis of rhodium complexes with weakly binding highly fluorinated benzene ligands is described: 1,2,3‐F3C6H3, 1,2,3,4‐F4C6H2 and 1,2,3,4,5‐F5C6H are shown to bind with cationic [Rh(Cy2P(CH2)xPCy2)]+ fragments (x=1, 2). Their structures and reactivity with alkenes, and use in catalysis for promoting the Tishchenko reaction of a simple aldehyde, are demonstrated. Key to the synthesis of these complexes is the highly concentrated reaction conditions and use of the [Al{OC(CF3)3}4]− anion.

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Binding energies of chromium cations with fluorobenzenes from radiative association kinetics

Cited by 22 publications

References 18 publications

Reactivity and binding energies of transition metal halide ions with benzene

Reactivity and binding energies of transition metal halide ions with benzene

Radiative Association Reactions of Na⁺, Mg⁺, and Al⁺ with Abundant Interstellar Molecules. Variational Transition State Theory Calculations

Synthesis of Highly Fluorinated Arene Complexes of [Rh(Chelating Phosphine)]⁺ Cations, and their use in Synthesis and Catalysis

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Binding energies of chromium cations with fluorobenzenes from radiative association kinetics

Cited by 22 publications

References 18 publications

Reactivity and binding energies of transition metal halide ions with benzene

Reactivity and binding energies of transition metal halide ions with benzene

Radiative Association Reactions of Na+, Mg+, and Al+ with Abundant Interstellar Molecules. Variational Transition State Theory Calculations

Synthesis of Highly Fluorinated Arene Complexes of [Rh(Chelating Phosphine)]+ Cations, and their use in Synthesis and Catalysis

Contact Info

Product

Resources

About

Radiative Association Reactions of Na⁺, Mg⁺, and Al⁺ with Abundant Interstellar Molecules. Variational Transition State Theory Calculations

Synthesis of Highly Fluorinated Arene Complexes of [Rh(Chelating Phosphine)]⁺ Cations, and their use in Synthesis and Catalysis