A combined experimental, theoretical, and Van't Hoff model study for identity methyl, proton, hydrogen atom, and hydride exchange reactions. Correlation with three‐center four‐, three‐, and two‐electron systems

Buck, HM Henk

doi:10.1002/qua.21683

Cited by 12 publications

(44 citation statements)

References 72 publications

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“…The X-ray data give for the short and long bond distance DFT values of 1.77Å and 2.77Å with a ratio of 1.56. Summarizing, the geometric switch is the consequence of change in electronegativity from -BCl 2 into -BF 2 [12] [19]. Trigonal bipyramids as pentavalent configurations are mostly found for silicon, phosphorus and sulfur with R(d)-values (much) smaller than the critical value of 1.333.…”

Section: Introductionmentioning

confidence: 99%

A Molecular Description of Superconductivity of Sulfur Hydride and Related Systems under High-Pressure Conditions

Buck¹

2017

OJPC

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It has been shown that the recently discovered sulfur trihydride (H 3 S) can be considered as a superconductor with a transition temperature Tc of 203 Kelvin (K) at 155 GigaPascals (GPa). This is the highest Tc value reported for any superconductor. The established superconductivity occurs via the formation of a molecular system with sulfur atoms arranged on a body-centered cubic lattice. It has been generally accepted that the high Tc value is the result of an efficient electron-phonon interaction. The responsible substance formed by H 2 S under high pressure, may be considered as a compound with H 3 S stoichiometry creating an impressive network with hydrogens. We will focus on the hydrogen bonding between sulfur and hydrogens demonstrating a symmetrical arrangement. The geometry of the individual radical compound in relation to corresponding systems will be discussed. Ab initio calculations based on a linear three-center two-, three-and four-electron type of bonding clearly visualized in combination with the dynamics of the Van't Hoff concept, as described by us in various papers, give a good description of this exclusive network. We also discuss the superconductivity of related phosphorus hydrides and focus on the stability and geometrical differences with respect to the H 3 S system. These differences are significant, demonstrating the diversity in various structures in showing superconductivity.

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Section: Introductionmentioning

confidence: 99%

A Molecular Description of Superconductivity of Sulfur Hydride and Related Systems under High-Pressure Conditions

Buck¹

2017

OJPC

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“…Most of these interactions were focused on wellknown reaction types, theoretically described with experimental evidence for complex models. In these studies, three-center four-, three-, and two-electron systems based on carbon-, boron-, hydrogen-, and halogen exchange reactions were studied along the lines of ab initio and Van't Hoff (vtH) modelling studies [1]- [7]. In the case of a linear three-center model, it was possible with the dynamics of a regular tetrahedron to change its geometry into a trigonal bipyramidal transition-or intermediate complex, to predict the various bond lengths at specific locations on the reaction profile.…”

Section: Introductionmentioning

confidence: 99%

“…The results are given in Table 1 in combination with ab initio results [1] [3] [4]. The computations using relativistic DFT at the ZORA-OL0.YP/TZ2P level are obtained from Bento et al [8] [9], the other data from Glukhovtsev et al [10].…”

Section: Introductionmentioning

confidence: 99%

Interconversion between Planar-Triangle, Trigonal-Pyramid and Tetrahedral Configurations of Boron (B(OH)3 -B(OH)4- ), Carbon (CH3+ -CH3X) and for the Group 15 Elements as Nitrogen (NH3-NH4<sup

Buck¹

2015

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“…For the hydrogen atom transfer for methane the ratio number is 1.235, corresponding with a linear mode [2]. From a more general view it is clear that reduction of the number of electrons involved in the threecenter bonding may result in a geometric change of the CHC angle.…”

Section: Hydrogen and Fluor Transitions As Divalent Atoms In A Three-mentioning

confidence: 99%

“…The hydrogen transfer reactions for linear three-center identity proton, hydrogen atom, and hydride anion (C-H…C) are also connected with the ratio numbers (103.2˚) [2]. For the hydrogen atom transfer for methane the ratio number is 1.235, corresponding with a linear mode [2].…”

Section: Hydrogen and Fluor Transitions As Divalent Atoms In A Three-mentioning

confidence: 99%

Three-Center Configuration with Four,Three, and Two Electrons for Carbon,Boron, Hydrogen, and Halogen Exchange. A Model and Theoretical Study with Experimental Evidence

Buck¹

2014

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The introduction of specific sites in organic frames for accommodation of various modes of bonding has been focused on reaction types which are described by using different theoretical models with or without a definite experimental proof. In this study three-center four-, three-, and twoelectron systems based on carbon-, boron-, hydrogen-, and halogen exchange are under consideration. Based on the number of electrons in the transition state or transition complex it is shown that all transfer or exchange reactions share the same ratio numbers expressed as the quotient of the transitional bond distance under investigation and its normal bond length. With X-ray data of model systems it was even possible to give the ratio numbers for a three-center four-electron configuration experimental support with additional ab initio data. Furthermore a novel model type of substitution in organic chemistry is introduced through electrophilic insertion, informative for enzyme-substrate interactions based on the lock-and-key model. Reactions based on a three-center two-electron configuration mostly follow a nonlinear transition. In this alignment there will be a pursuit of cyclization for stabilization via homoaromaticity as homocyclopropenyl cation. The molecular dynamics of such a process is discussed based on recent X-ray crystallographic data of the symmetrically bridged, nonclassical geometry of the 2-norbornyl cation. In the present paper the focus is aimed at the transition intermediate of the (classical) 2-norbornyl cation involved in the isomerization into the nonclassical geometry. This model description is compared with a simple molecular rearrangement of the 1-propyl cation into the corner-protonated cyclopropane using the ab initio data. The exclusivity of the former isomerization compared with the latter one could be unambiguously demonstrated by the invention that the intramolecular electron shift can be expressed in a linear relationship between the concerned electron-donating and accepting H. M. Buck 34 bond lengths. Finally, the fluor transitions as divalent atoms in a three-center two-electron configuration are described. The role of fluor in comparison with the other halogens is striking. The attention was focused on an excellent correspondence between the recent chemical and theoretical evidence for a symmetrical fluoronium ion in solution. Simple dialkylfluoroniumions in contrast to the other halonium ions are not present in solution. Although the geometry of the fluoronium ion theoretically can be described as a real minimum, the C-F-C angle of 120˚ is apparently the borderline transition for dissociation in C + and F-C.

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A combined experimental, theoretical, and Van't Hoff model study for identity methyl, proton, hydrogen atom, and hydride exchange reactions. Correlation with three‐center four‐, three‐, and two‐electron systems

Cited by 12 publications

References 72 publications

A Molecular Description of Superconductivity of Sulfur Hydride and Related Systems under High-Pressure Conditions

A Molecular Description of Superconductivity of Sulfur Hydride and Related Systems under High-Pressure Conditions

Interconversion between Planar-Triangle, Trigonal-Pyramid and Tetrahedral Configurations of Boron (B(OH)<sub>3</sub> -B(OH)<sub>4</sub><sup>-</sup> ), Carbon (CH<sub>3</sub><sup>+</sup> -CH<sub>3</sub>X) and for the Group 15 Elements as Nitrogen (NH<sub>3</sub>-NH<sub>4</sub><sup

Three-Center Configuration with Four,Three, and Two Electrons for Carbon,Boron, Hydrogen, and Halogen Exchange. A Model and Theoretical Study with Experimental Evidence

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