Further relationships between theoretical and experimental models of electrophilicity and nucleophilicity

Chamorro, Eduardo; Duque-Noreña, Mario; Pérez, Patricia

doi:10.1016/j.theochem.2009.01.014

Cited by 37 publications

(19 citation statements)

References 104 publications

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“…In fact, good correlations have been obtained by various groups, between the global electrophilicities of a family of substituted compounds and some constant related with their reactivity. Examples include linear relationships involving global or group electrophilicities in a variety of processes, such as the reactivity of benzhydryl carbocations, 19,22 in the Baeyer-Villiger reaction of aldehydes and ketones, 23 in the hydride affinities of quinones, 24 in the reaction of aryl benzoates with cyanide, 25 or of a,b-unsaturated carbonyl compounds with glutathione. 26 These examples only add to the ones presented in the present work.…”

Section: Discussionmentioning

confidence: 99%

“…19 Correlation coefficients of R 2 = 0.95 and 0.89 were obtained, when the theoretical electrophilicities were calculated with an HF or a B3LYP method, respectively. This result is in apparent contradiction with the linear dependence of E on s w p for the same family of compounds, shown in Figure 6.…”

Section: Correlation With An Experimental Electrophilicity Parametermentioning

confidence: 98%

“…An explanation for this apparent contradiction lies on the fact that Chamorro et al 19 employed for their correlations a set of diarylcarbenium ions with strongly nucleophilic alkylamino substituents, and corresponding E values in the range of -10.4 to -5.53. Deviations from linearity in plots of E vs. w should not be apparent when a small range of E values is considered.…”

Section: Correlation With An Experimental Electrophilicity Parametermentioning

confidence: 99%

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Theoretical substituent electrophilicities

Rezende¹,

Millán²

2011

J. Braz. Chem. Soc.

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Uma equação de tipo Hammett, relacionando as eletrofilicidades teóricas globais e de substituinte, foi derivada para etilenos e ácidos benzóicos substituídos, permitindo o cálculo de constantes eletrofílicas para substituintes s w . As constantes teóricas foram correlacionadas com parâmetros cinéticos ou termodinâmicos para vários processos químicos da literatura. Embora formalmente semelhantes às constantes de Hammett, as constantes eletrofílicas para substituintes são obtidas a partir de postulados teóricos inteiramente distintos. As semelhanças e diferenças entre os dois conjuntos de constantes são discutidas e racionalizadas em termos da definição do poder eletrofílico de uma espécie química.A Hammett-like equation, relating theoretical global and substituent electrophilicities, is derived for substituted ethylenes and benzoic acids, allowing the calculation of electrophilic substituent constants s w . Correlations are given between the theoretical s w constants and kinetic or thermodynamic parameters of various chemical processes from the literature. Though electrophilic substituent constants are formally similar to the Hammett constants, they are derived from entirely different theoretical postulates. The similarities and differences between the two sets of constants are discussed and rationalized in terms of the definition of the electrophilic power of a chemical species.

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Section: Discussionmentioning

confidence: 99%

Section: Correlation With An Experimental Electrophilicity Parametermentioning

confidence: 98%

Section: Correlation With An Experimental Electrophilicity Parametermentioning

confidence: 99%

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Theoretical substituent electrophilicities

Rezende¹,

Millán²

2011

J. Braz. Chem. Soc.

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“…In the comparison of piperidine, piperazine, Nmethylpiperazine, and morpholine (Table 3), it is quite interesting and a wonder that only piperazine and N-methylpiperazine can be involved in such reactions, but the piperidine and morpholine cannot react with 4-chlorobenzyl cation to lose HCl. Experimental and theoretical studies indicate that the nucleophilicity of piperidine is stronger than that of piperazine [54,55], so the nucleophilicity is probably not the reason. When the amine is diethylamine, diisopropylamine, or pyrrolidine, the loss of HCl is not observed as well ( Figures S24-S26 in the online supplementary material).…”

Section: Nucleophilic Aromatic Substitutionmentioning

confidence: 99%

Gas-Phase Chemistry of Benzyl Cations in Dissociation ofN-Benzylammonium andN-Benzyliminium Ions Studied by Mass Spectrometry

Chai

Wang

Sun

et al. 2012

J. Am. Soc. Mass Spectrom.

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In this study, the fragmentation reactions of various N-benzylammonium and N-benzyliminium ions were investigated by electrospray ionization mass spectrometry. In general, the dissociation of N-benzylated cations generates benzyl cations easily. Formation of ion/neutral complex intermediates consisting of the benzyl cations and the neutral fragments was observed. The intra-complex reactions included electrophilic aromatic substitution, hydride transfer, electron transfer, proton transfer, and nucleophilic aromatic substitution. These five types of reactions almost covered all the potential reactivities of benzyl cations in chemical reactions. Benzyl cations are well-known as Lewis acid and electrophile in reactions, but the present study showed that the gas-phase reactivities of some suitably ring-substituted benzyl cations were far richer. The 4-methylbenzyl cation was found to react as a Brønsted acid, benzyl cations bearing a strong electron-withdrawing group were found to react as electron acceptors, and parahalogen-substituted benzyl cations could react as substrates for nucleophilic attack at the phenyl ring. The reactions of benzyl cations were also related to the neutral counterparts. For example, in electron transfer reaction, the neutral counterpart should have low ionization energy and in nucleophilic aromatic substitution reaction, the neutral counterpart should be piperazine or analogues. This study provided a panoramic view of the reactions of benzyl cations with neutral N-containing species in the gas phase.

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“…Mechanisms of electrophile-nucleophile combinations have been studied using the global electrophilicty index () (Parr, Szentpaly, & Liu, 1999). Recently it has been used to study polar Diels-Alder reactions (Domingo & Saez 2009), the reactions of superelectrophiles with aromatic and heteroaromatic compounds (Lakhdar et al, 2010), and the reaction of benzhydryl cations (Chamorro, Duque-Norena, & Perez, 2009a, 2009b-systems that involve electrophile-nucleophile combinations (Terrier, Dust, & Buncel, 2012). In order to gain a greater insight into the possible mechanisms of the reactions of 1-substituted pyrroles with an N-halo compound the  values of the N-halo compounds used were calculated.…”

Section: Scheme 2 Possible Mechanistic Pathwaysmentioning

confidence: 99%

Global Electrophilicity Study of the Reaction of Pyrroles with N-Halo Compounds and the Rate-Determining Step

Rosa¹,

Kim²

2013

IJC

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Pyrroles (nucleophiles) can react with N-halo compounds (electrophiles) to give either addition-elimination or halogenation products. Global electrophilicity () has been used to study electrophile-nucleophile combinations.The  values of the N-halo compounds (n = 22) used were calculated using DFT/B3LYP. No correlation was observed between  and the pathway of reaction/non-reaction. A single parameter () could not explain the results of the competing reactions that are taking place in this system-reactions that appear to depend on the N-halogen (Cl, Br, I) nucleophilicity/basicity and possibly hardness of the leaving group. These calculations confirmed that the rate-determining step of the addition-elimination process was not the formation of an -complex, but its subsequent reaction. Calculations suggested that deprotonation of the -complex was the rate-determining step in the halogenation reactions. It was also possible to examine the effects of the structure of the N-halo-compound and the halogen.

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Further relationships between theoretical and experimental models of electrophilicity and nucleophilicity

Cited by 37 publications

References 104 publications

Theoretical substituent electrophilicities

Theoretical substituent electrophilicities

Gas-Phase Chemistry of Benzyl Cations in Dissociation ofN-Benzylammonium andN-Benzyliminium Ions Studied by Mass Spectrometry

Global Electrophilicity Study of the Reaction of Pyrroles with N-Halo Compounds and the Rate-Determining Step

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