Molecular orbital theory of the electronic structure of molecules. 30. Structure and energy of the phenyl cation

Dill, James D.; Schleyer, Paul v. R.; Binkley, J. Stephen; Seeger, Rolf; Pople, John A.; Haselbach, Edwin

doi:10.1021/ja00434a002

Cited by 83 publications

(47 citation statements)

References 7 publications

(8 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hartree-Fock is known to give lower energies for triplets, which have smaller correlation energies [49]. Almost all DFT methods cluster between 76 and 97 kJ/mol.…”

Section: Resultsmentioning

confidence: 99%

“…Table 5 calculated at the G4(MP2) level and the corresponding Hammett (a) σ m and σ p and (b) σ p + substituent constants In addition, the current findings support prior theoretical work explaining why aryl cations have differing ground state multiplicities depending on the type and location of substituents. The singlet ground state and two ( 3 B 1 , 3 A 2 ) low-lying triplet excited states are known to have different geometric and electronic structures [49]. For the singlet, the positive charge resides in the σ system; however, for the triplets the cation is delocalized throughout the π system.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Singlet–triplet excitation energies of substituted phenyl cations: a G4(MP2) and G4 theoretical study

Rayne¹,

Forest

2016

Theor Chem Acc

View full text Add to dashboard Cite

“…Hartree-Fock is known to give lower energies for triplets, which have smaller correlation energies [49]. Almost all DFT methods cluster between 76 and 97 kJ/mol.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Singlet–triplet excitation energies of substituted phenyl cations: a G4(MP2) and G4 theoretical study

Rayne¹,

Forest

2016

Theor Chem Acc

View full text Add to dashboard Cite

“…This is interesting, since the diazonio group is probably the best leaving group known, and one would expect even the relatively unstable primary vinyl cations to be accessible by heterolytic dediazoniation. Phenyl cations, which according to MO calculations have a stability comparable to that of primary vinyl cations [41], are easily formed this way. The answer to this problem may be the recent conclusion based on the comparison of thermodynamic and solvolysis data for vinyl systems with ab initio MO calculations [42], namely that the difficult formation of vinyl cations is not primarily due to their low stability, but to an unusually high kinetic barrier between vinyl derivatives and the corresponding ionic intermediates.…”

mentioning

confidence: 98%

Reactions of Alkenediazonium Salts. Part 1. 2,2‐Diethoxyethene‐diazonium hexachloroantimonate: A diazonium, a carbenium or an oxonium salt?

Szele¹,

Tencer²,

Zollinger³

1983

Helvetica Chimica Acta

View full text Add to dashboard Cite

SummaryReactions of the title compound 1 with various nucleophiles have been studied. The salt behaves like an alkylating agent towards ethers, alcohols and water forming ethyl diazoacetate (2), which reacts further with excess of the nucleophile. A solvent cage mechanism accounting for the observed products is proposed. Thermal decomposition in inert solvents leads to the alkylation of the counter-ion, i.e. formation of chloroethane, and in anisole, alkylation and chlorination of the solvent are also observed.With a standard coupling component, 2-naphtholate ion, no azo coupling reaction of 1 is observed, but instead 14-methyl-14H-dibenzo [a,j]xanthene (17) is formed. The products of the reaction with diethylamine are diethylcyanoformamide (18) and ethyl diethylcarbamate (19). None of the chemistry of salt 1 is explained by the intervention of vinyl cations expected to be formed in a heterolytic dediazoniation. The predominant pathways seem to involve reactions of an oxonium salt (alkylating properties) or, in the case of diethylamine, a carbenium salt (primary nucleophilic attack on the p-C-atom of 1).The free energy barrier to C=C rotation in 1 is estimated to be 75 to 77 kJ/mol (18.0 to 18.5 kcal/mol), a value which falls between those expected for a double and a single bond.Introduction. -In the context of our investigations on the dediazoniation mechanism of aromatic diazonium ions'), comparisons with the reactivity of vinyldiazonium ions are interesting. Owing to their electronic similarity vinyldiazonium ions might be reagents for the formation of vinyl cations.The unsubstituted vinyldiazonium ion, H,C=CH-N,+, is not yet known. Therefore a theoretical study on the vinyldiazonium ion in the gas phase and in aqueous solution is a worthwhile undertaking. With others, we recently made such a study [2] for the gas phase by ab initio (STO-3G and 4-31G), and for solution by CND0/2 methods. This investigation is a continuation of previous theoretical

show abstract

“…Advanced computational studies gave a clear insight into the geometry, electronic structure, and energetic state of this cation [32,33]. Therewith, for the model the referees considered removal of the hydride ion from benzene, which gives the phenyl cation in the ground singlet state.…”

mentioning

confidence: 99%

Effect of the Electronic Structure of Carbenium and Silylium Ions on Their Chemical Behavior

2005

View full text Add to dashboard Cite

Being isoelectronic analogs, silylium and carbenium ions exhibit quite a different reactivity toward nucleophiles. This is explained by their different electronic structures and charge distributions: In silylium ions the positive charge is almost completely concentrated on the silicon atom, and hydrogen atoms on the cationic center are hydride in nature, wheteas in carbenium ions, the positive charge is uniformly distributed between the carbenoid center and hydrogen atoms. Carbenium ions R 3 C + and their isoelectronic analogs, silylium ions R 3 Si + (R = H, Alk), are shortlived reactive intermediates whose properties determine the mechanism and direction on many chemical reactions. Therefore, transformations of these cations attract enduring researcher's attention. The role of carbenium ions in organic chemistry is well-known: They take part in most reactions. The information on reactions of silylium ions has long been very scarce, and these ions have long been considered to behave similarly to carbenium ions. In earlier works silylium ions have even been postulated as intermediates in many organosilicon reactions, such as catalytic disproportionation of alkylchlorosilanes [133]. However, no clear evidence to show that silylium ions are involved in such reactions has not been provided.The problem is made even more intricate by the fact that silylium ions are impossible to detect in condensed media, even though they are thermodynamically more stable and easier formed in the gas phase compared with carbenium ions. Gas-phase reactions of silylium ions with nucleophiles have been studied mostly by mass spectrometry and ioncyclotron resonance, and these studies focused on the observation of adducts, i.e. complexes of the ions with nucleophiles. These studies gave estimates for the reactivity of silylium ions but gave no idea of the direction and mechanisms of the overall reactions. Thus, traditional methods for generation, observation, and study of carbenium ions proved absolutely unsuitable for silylium ions.In [4,5] we proposed a unique nuclear chemical technique for generation of silylium ions of the desired composition and structure (with a preset charge localization) in the gas and condensed phases. This technique is based on b-decay of tritium incorporated in substituted silanes. R 43n SiT n 76 [R 43n SiT n31 He] + 76 R 43n Si + T n31 + He. b !Reactions of thus generated silylium ions with nucleophiles have been studied by the radiochemical method that allows observation of neutral reaction products, including isomers.Previously we performed a radiochemical study of ion3molecule reactions of ethyl-and diethylsilylium ions with benzene [638], alcohols [9][10][11], and organic [12] and organosilicon [13] ethers and amines [14,15] in the gas and condensed phases. We suggested mechanisms of these reactions and revealed features that distinguish them from reactions of carbenium ions. Of special mention are reactions of silylium ions with organosilicon amines and benzene. It is these reactions that the differences in...

show abstract

Molecular orbital theory of the electronic structure of molecules. 30. Structure and energy of the phenyl cation

Cited by 83 publications

References 7 publications

Singlet–triplet excitation energies of substituted phenyl cations: a G4(MP2) and G4 theoretical study

Singlet–triplet excitation energies of substituted phenyl cations: a G4(MP2) and G4 theoretical study

Reactions of Alkenediazonium Salts. Part 1. 2,2‐Diethoxyethene‐diazonium hexachloroantimonate: A diazonium, a carbenium or an oxonium salt?

Effect of the Electronic Structure of Carbenium and Silylium Ions on Their Chemical Behavior

Contact Info

Product

Resources

About