Inapplicability of the Antiperiplanar Lone Pair Hypothesis to C−P Bond Breaking and Formation in Some S−C−P<sup>+</sup>Systems

Graczyk, Piotr; Mikołajczyk, M.

doi:10.1021/jo941771m

Cited by 8 publications

(7 citation statements)

References 58 publications

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“…The comparison of σ C - H → σ* C - P and σ C - P → σ* C - H interactions is quite interesting since phosphorus has essentially the same electronegativity as hydrogen. As the result, polarization and donor ability of the C−PH 2 bond are essentially the same as that of the C−H bond.…”

Section: Resultsmentioning

confidence: 99%

Stereoelectronic Effects and General Trends in Hyperconjugative Acceptor Ability of σ Bonds

2002

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A systematic study of general trends in sigma acceptor properties of C-X bonds where X is a main group element from groups IVa-IIa is presented. The acceptor ability of the C-X sigma bonds in monosubstituted ethanes increases when going to the end of a period and down a group. Enhancement of acceptor ability of C-X sigma bonds as one moves from left to right in periods parallels the increase in electronegativity of X, whereas augmentation of acceptor ability in groups is opposite to the changes in electronegativity of X and in the C-X bond polarization, following instead the decrease in the energy of sigma(C)(-)(X) orbitals when one moves from the top to the bottom within a group. This simple picture of acceptor ability of sigma bonds being controlled by electronegativity in periods and by sigma orbital energy in groups is changed in monosubstituted ethenes where the role of electronegativity of the substituent X becomes more important due to increased overlap between sigma orbitals. The combination of several effects of similar magnitude influences acceptor ability of sigma bonds in monosubstituted ethenes in a complex way. As a result, the acceptor ability of sigma bonds can be significantly modified by substitution and is conformer dependent. Stereoelectronic effects displayed by C-X bonds with X from second and third periods are highly anisotropic. For example, C-chalcogen bonds are excellent sigma acceptors at the carbon end but poor sigma acceptors at the chalcogen end. This effect can be relied upon in the design of molecular diodes with sigma bridges with unidirectional electron conductivity. While the general trends revealed in this work should be useful for the qualitative understanding of stereoelectronic effects, one should bear in mind that the magnitude of hyperconjugative effects is extremely sensitive to small variations in structure and in substitution. This advocates for the increased role of theoretical methods in analysis of stereoelectronic effects.

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Section: Resultsmentioning

confidence: 99%

Stereoelectronic Effects and General Trends in Hyperconjugative Acceptor Ability of σ Bonds

2002

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“…It is still an area of considerable uncertainty and controversy, 8 with wide acceptance 9 and only occasional skepticism. 10 Much of the interest is for purposes of synthesis, where it offers a novel method for control of stereochemistry. Customarily steric effects are used to direct an incoming nucleophile along the least hindered path.…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Catalysis and Apparent Stereoelectronic Control in Hydrolysis of Cyclic Imidatonium Ions

2000

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To test stereoelectronic control in cleavage of tetrahedral intermediates, cyclic imidatonium ions were hydrolyzed in buffered aqueous media. In carbonate buffer >97% amino ester was observed, as previously reported. However, in borate buffers 65−91% hydroxy amide was observed from five-membered-ring imidatonium ions, except for a highly alkylated one. Selectivity is attributed to leaving-group ability. Stereoelectronic control does operate in six-membered rings but provides only 2 kcal/mol toward rate acceleration. Production of amino ester in carbonate buffers is due to the bifunctional nature of bicarbonate ion and thus cannot be used to support a large stereoelectronic contribution. The geometrical requirements for bifunctional catalysis further imply the intermediacy of conformations counter to stereoelectronic control.

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“…The additional bonding of C-P is beneficial to constructing the S-C-P moiety and forming the analogues of Lawesson's reagent [18,19], which could promote the reactivity for sulfonation. Coupled with the industrial method for Na 2 S production (Na 2 SO 4 + 2C → Na 2 S + CO 2 ), we report an effective method to prepare the HCSC as illustrated in Fig.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

The bond evolution mechanism of covalent sulfurized carbon during electrochemical sodium storage process

Zhang

Zou

et al. 2019

Sci. China Mater.

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The excellent energy storage performance of covalent sulfur-carbon material has gradually attracted great interest. However, in the electrochemical sodium storage process, the bond evolution mechanism remains an elusive topic. Herein, we develop a one-step annealing strategy to achieve a high covalent sulfur-carbon bridged hybrid (HCSC) utilizing phenylphosphinic acid as the carbon-source/catalyst and sodium sulfate as the sulfur-precursor/salt template, in which the sulfur mainly exists in the forms of C-S-C and C-S-S-C. Notably, most of the bridge bonds are electrochemically cleaved when the cycling voltage is lower than 0.6 V versus Na/Na + , leading to the appearance of two visible redox peaks in the following cyclic voltammogram (CV) tests. The in-situ and ex-situ characterizations demonstrate that S 2− is formed in the reduction process and the carbon skeleton is concomitantly and irreversibly isomerized. Thus, the cleaved sulfur and isomerized carbon could jointly contribute to the sodium storage in 0.01-3.0 V. In a Na-S battery system, the activated HCSC in cut off voltage window of 0.6-2.8 V achieves a high reversible capacity (770 mA h g −1 at 300 mA g −1). This insight reveals the charge storage mechanism of sulfur-carbon bridged hybrid and provides an improved enlightenment on the interfacial chemistry of electrode materials.

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Inapplicability of the Antiperiplanar Lone Pair Hypothesis to C−P Bond Breaking and Formation in Some S−C−P⁺Systems

Cited by 8 publications

References 58 publications

Stereoelectronic Effects and General Trends in Hyperconjugative Acceptor Ability of σ Bonds

Stereoelectronic Effects and General Trends in Hyperconjugative Acceptor Ability of σ Bonds

Bifunctional Catalysis and Apparent Stereoelectronic Control in Hydrolysis of Cyclic Imidatonium Ions

The bond evolution mechanism of covalent sulfurized carbon during electrochemical sodium storage process

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Inapplicability of the Antiperiplanar Lone Pair Hypothesis to C−P Bond Breaking and Formation in Some S−C−P+Systems

Cited by 8 publications

References 58 publications

Stereoelectronic Effects and General Trends in Hyperconjugative Acceptor Ability of σ Bonds

Stereoelectronic Effects and General Trends in Hyperconjugative Acceptor Ability of σ Bonds

Bifunctional Catalysis and Apparent Stereoelectronic Control in Hydrolysis of Cyclic Imidatonium Ions

The bond evolution mechanism of covalent sulfurized carbon during electrochemical sodium storage process

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Product

Resources

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Inapplicability of the Antiperiplanar Lone Pair Hypothesis to C−P Bond Breaking and Formation in Some S−C−P⁺Systems