Efficient and accurate calculation of anion proton affinities

Chandrasekhar, Jayaraman; Andrade, Juan G.; Schleyer, Paul von Ragué

doi:10.1021/ja00408a074

Cited by 304 publications

(111 citation statements)

References 4 publications

Supporting

Mentioning

106

Contrasting

Unclassified

Order By: Relevance

“…5 kcal mol-' based on the assumption that the replacement of H by CH, in CH, could lead to either an increase or decrease in electron affinity. Calculations at the 4-31 +G level (16,17) show a destabilization by CH, for H substitution of 5.6 kcal mol-'; however, at the same level, the calculations fail to reproduce the relative experimental order of stabilities of NH,-and CH3NH-and fail to indicate the large stabilization of CH,Orelative to OH-. ' Thus we feel that relative to the experimental EA(CH,) of 2 kcal mol-' (29) With the advantage of hindsight it is possible to rationalize the instability of the P-fluoroethyl carbanion toward dissociation to F-and C2H4 and the greater stability of the hydrogen bonded complex on purely thermochemical grounds.…”

Section: C2h$f-mentioning

confidence: 96%

“…All structures were fully optimized using the 4-3 1G basis set employing an analytical gradient technique (15). In several cases single point total energy calculations were carried out for the 4-31G optimized geometry using the 4-3 1 +G basis set (16,17). This latter basis set, incorporating additional flat s and p Gaussian functions on all heavy atoms has been demonstrated by Schleyer to provide a much more accurate description of the energetics of anions than other split valence basis sets.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F⁻ and sp² and sp C—H bonds

Roy¹,

Mcmahon²

1985

Can. J. Chem.

View full text Add to dashboard Cite

Abinitio quantum chemical techniques have been used to investigate the structures and energetics of a number of hydrogen bonded adducts of F− and C—H bonds associated with unsaturated systems as well as their structural isomers. Examination of the possible species of molecular formula C2H4F− reveals that the most stable isomer is a hydrogen bonded adduct of F− and ethylene, while the classical β-fluoroethyl carbanion is found not to be bound with respect to dissociation into F− + C2H4. Similar examination of C2H2F− isomers shows that a hydrogen bonded F−–acetylene adduct is the most stable structure, however, the remaining α and β-fluorovinyl carbanions are found to be bound with respect to F− + C2H2. These results are used to explain the unusual gas phase acidities of ethylfluoride and vinylfluoride. Calculations on C3H4F− isomers show the hydrogen bonded adduct of F− and allene to be more stable than the classical 2-fluoropropenyl anion and on C2H2FO− isomers show the enolate of acetyl fluoride to be more stable than the hydrogen bonded adduct of F− and ketene. These latter results are used to explain the gas phase ion molecule reactivities of C3H4F− (predominantly F− transfer) and C2H2FO− (proton abstraction).

show abstract

Section: C2h$f-mentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F⁻ and sp² and sp C—H bonds

Roy¹,

Mcmahon²

1985

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Thus, while the isopropyl cation and radical can be observed directly in condensed phases and their energies are established from gas phase measurements, the isopropyl anion is unknown and appears to be incapable of existence as an isolated entity. The methyl radical has an electron affinity of only 1.84 kcal/mol methyl groups in the higher alkyl anions are destabilizing (2). Hence, the isopropyl anion is not expected to be bound and would eject an electron spontaneously in the gas phase.…”

Section: Introductionmentioning

confidence: 99%

Lithium synthetic reagents: dimerization and intramolecular association. Double bridging in "dianions"

Schleyer¹

1983

Pure and Applied Chemistry

124

View full text Add to dashboard Cite

-The dimerization energies of lithium compounds, 2LiX-(LiX)9, are quite large and depend principally on the electronegativity of X. Intramoleular association, the equivalent of dimerization, is comparably favorable energetically. Thus, many polylithium compounds, including many synthetically useful "dianions", are found by molecular orbital calculations to prefer structures in which the lithium atoms bridge symmetrically. An example is o,o'-dilithiobiphenyl, whose predicted structure has now been confirmed by X-ray spectroscopy. Dilithiated species based on propene (CH9CHCHLi9), propane (LiCH9CH9CH9Li), acetaldehyde (Li CHCHO), acetone (LiCH2COH Li ahd Li CHCOCH), ahd mies (e.g., HCOLi9) are amog 1,3-double bridging examles. Besies o,o -dilithiobiphenyl, 1,4-double lithium bridging is exhibited by 1,4-dilithiobutane, 1,4-dilithio-2-cis-butene, and 1,4-dilithio-1,3-cis,cis-butadiene. While electrostatic interactions provide the simplest explanation for these structures, multi center covalent bonding also is important in determining geometrical details and energetic differences.

show abstract

“…Geometry optimizations and harmonic vibrational frequency calculations were performed at B3LYP/6-311++G(d,p) level of theory [25][26][27][28][29][30][31]. In the case of openshell systems, spin-unrestricted calculations (UB3LYP) were used.…”

Section: Computationalmentioning

confidence: 99%

Investigation of Fragmentation of Tryptophan Nitrogen Radical Cation

Piatkivskyi

Happ

Lau

et al. 2015

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Abstract. This work describes investigation of the fragmentation mechanism of tryptophan N-indolyl radical cation, H 3 N + -TrpN • (m/z 204) studied via DFT calculations and several gas-phase experimental techniques. The main fragment ion at m/z 131, shown to be a mixture of up to four isomers including 3-methylindole (3MI) π-radical cation, was found to undergo further loss of an H atom to yield one of the two isomeric m/z 130 ions. 3-Methylindole radical cation generated independently (via CID of [Cu II (terpy)3MI] •2+ ) displayed gas-phase reactivity partially similar to that of the m/z 131 fragment, further confirming our proposed mechanism. CID of deuterated tryptophan N-indolyl radical cation (m/z 208) suggested that up to six H atoms are involved in the pathway to formation of the m/z 131 ion, consistent with hydrogen atom scrambling during CID of protonated Trp.

show abstract

Efficient and accurate calculation of anion proton affinities

Cited by 304 publications

References 4 publications

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F⁻ and sp² and sp C—H bonds

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F⁻ and sp² and sp C—H bonds

Lithium synthetic reagents: dimerization and intramolecular association. Double bridging in "dianions"

Investigation of Fragmentation of Tryptophan Nitrogen Radical Cation

Contact Info

Product

Resources

About

Efficient and accurate calculation of anion proton affinities

Cited by 304 publications

References 4 publications

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F− and sp2 and sp C—H bonds

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F− and sp2 and sp C—H bonds

Lithium synthetic reagents: dimerization and intramolecular association. Double bridging in "dianions"

Investigation of Fragmentation of Tryptophan Nitrogen Radical Cation

Contact Info

Product

Resources

About

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F⁻ and sp² and sp C—H bonds

The anomalous gas phase acidity of ethyl fluoride. An abinitio investigation of the importance of hydrogen bonding between F⁻ and sp² and sp C—H bonds