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Pankratov, A. N.; Uchaeva, I. M.; Doronin, S. Yu.; Chernova, R. K.

doi:10.1023/a:1017909131054

Cited by 35 publications

(15 citation statements)

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“…We found that the MNDO, AM1, and PM3 methods correctly reproduce the most important thermodynamic and molecular characteristics [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], electronegativities, and inductive and mesomeric parameters of groups of atoms [48,49] is series of compounds. Among these methods, only PM3 yields reasonable results for the heats of formation of nitroso compounds [24,30] and dimethyl sulfone [32].…”

Section: Resultsmentioning

confidence: 99%

Quantitative structure-property relationships in the series of diazonium cations, intermediate products in the synthesis of analytical forms and dyes

Pankratov

2005

J Anal Chem

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It was demonstrated that the reduction potentials, dimerization potentials, and half-equivalence point potentials in the titration of aryldiazonium cations XC 6 H 4 N + ≡ N are linearly related to the quantum-chemically calculated values of electron affinities ( A ) and stabilization energies of radicals formed in the reduction of diazonium cations. Linear correlations between the frequencies ( ν ) characterizing the set of stretching vibrations in the C -N + ≡ N fragment of XC 6 H 4 N + ≡ N cations and N ≡ N and C-N bond orders, charges on carbon atoms in the para positions of aromatic rings of C 6 H 5 X molecules, and mesomeric dipole moments ( µ m ) of substituents X were found. Quantitative relationships relating µ m and ν to A were revealed. These relationships have clear physical meaning, are characterized by relatively large correlation coefficients, and possess predictive power for redox properties, electron affinity, and vibrational spectra of aryldiazonium cations and mesomeric dipole moments of atomic groups in organic molecules.

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Section: Resultsmentioning

confidence: 99%

Quantitative structure-property relationships in the series of diazonium cations, intermediate products in the synthesis of analytical forms and dyes

Pankratov

2005

J Anal Chem

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Section: Resultsmentioning

confidence: 99%

Quantitative structure-property relationships in the series of diazonium cations, intermediate products in the synthesis of analytical forms and dyes

et al. 2005

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The azocoupling reaction of aromatic amines and phenols with aryldiazonium cations is of great importance for the production of dyes [1][2][3] and in analytical chemistry [4].Diazonium cations can be reduced either chemically or electrochemically [5][6][7][8][9][10][11][12]. For many compounds, the abilities to be subjected to electrophilic (nucleophilic) attack and to undergo oxidation (reduction) vary in parallel [13][14][15][16]. The susceptibility of diazo cations to reduction can serve as a measure of their electrophilic activity. Therefore, the a priori prediction of the reduction potentials and electron affinities of diazonium cations of the given structure and their subsequent directed synthesis is reasonable for the selection of the optimum reaction rates of the formation of azo dyes and analytical forms.Diazonium cations decompose to release molecular nitrogen [2,10,12,17]. To provide high yields of azo compounds and satisfactory accuracy, precision, and other performance characteristics of analytical procedures, it is desirable to avoid this competing reaction and to estimate quantitatively the degree of decomposition of newly synthesized diazonium salts.Among others, the stretching frequencies of the C -N + ≡ N group are a measure of the stability of diazonium cations (and simultaneously an indication of their activity as electrophilic agents) [17][18][19][20][21][22].As will be demonstrated below, vibrational frequencies and electron affinity correlate with the mesomeric dipole moments of substituents in aryldiazonium cations.The aim of this work was to find (based on quantumchemical calculations) quantitative structure-property relationships for the prediction of reduction potentials and some related quantities, electron affinities, stretching frequencies of the C -N + ≡ N group of aryldiazonium cations, and mesomeric dipole moments of groups of atoms.The correlations that are discussed in this work were presented in [23]. EXPERIMENTALCalculations were performed by the PM3 method [24] using the MOPAC program [25,26] with full geometry optimization (Broyden-Fletcher-GoldfarbShanno procedure [27]) using the Thiel algorithm for rapid minimization [28]. Preliminary optimization was performed by the molecular mechanics method (MMX procedure) [29] using the PCMODEL program [29]. In quantum-chemical calculations, we set the condition that the norm of the gradient was no higher than 0.084 kJ mol -1 Å -1 . In some cases, a sufficient decrease in the norm of the gradient was attained by the reject of Thiel rapid minimization (using the option NOTHIEL in the MOPAC program), by the optimization using the Davidon-Fletcher-Powell method (option DFP) [27], and by the combination of the approaches provided by the options NOTHIEL and DFP.For molecules with closed electronic shells, we used the restricted Hartree-Fock (RHF) method [26]. Radicals formed on the reduction of aryldiazonium salts were calculated by the unrestricted Hartree-Fock (UHF) method [26].Abstract -It was demonstrated that the reduction potentials,...

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“…[10,[36][37][38]. Further progress in the theory and computational capabilities of quantum-chemical methods led to more complicated models which should be classed with modern QSPR method discussed below.…”

Section: Previous Methods Of Calculation Of Ionization Constantsmentioning

confidence: 99%

“…Examples of molecular-tree structured fingerprint (MTSF) of morpholine molecule as numerical notation of the dependence of minimal energies (E min ) of interaction between O-probe and morpholine molecule on the topological distance (TP) to the oxygen atom therein [167]. QSPR calculations of pK a 's also utilized such descriptors as charges on atoms [37,38,158,175,190,201], group philicity [197], parameters of atoms relevant to molecular mechanics (SYBYL-type atoms) [173,174], empirical parameters included into free online SPARC package (see below) [198], semiempirical descriptors [37, 38, 163-165, 171, 172, 175, 190], and (less frequently) experimental physicochemical parameters [151,[163][164][165]. In the past decade, topological descriptors were used most extensively, in particular fragment descriptors [187], topological distances [167,173,174], 3D molecular interaction fields [167], molecular-tree structured fingerprints (MTSF) [162,167,173,174], and "quantum chemical topology" descriptors calculated in terms of the quantum similarity theory (QST) [161,169].…”

Section: Methods Based On Quantitative Structure-property Relationshimentioning

confidence: 99%

Modern methods for estimation of ionization constants of organic compounds in solution

Zevatskii

Samoilov²

2011

Russ J Org Chem

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The review considers main up-to-date approaches to the calculation of ionization constants of organic compounds in solutions. Methods based on quantum-chemical calculations, continuum solvent models, cluster models, and quantitative structure-property relationships are discussed. The results of calculations of pK a values by different methods, obtained in the past decade, are compared. REVIEW ACID IONIZATION CONSTANTS AND THEIR SIGNIFICANCEA quantitative parameter of acid-base properties of an HA molecule is the equilibrium constant for proton transfer (K a ) from acid HA to solvent molecule M with formation of lyonium ion and acid anion [1-3] (if an acid is an onium ion, neutral base is formed).

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Cited by 35 publications

References 10 publications

Quantitative structure-property relationships in the series of diazonium cations, intermediate products in the synthesis of analytical forms and dyes

Quantitative structure-property relationships in the series of diazonium cations, intermediate products in the synthesis of analytical forms and dyes

Quantitative structure-property relationships in the series of diazonium cations, intermediate products in the synthesis of analytical forms and dyes

Modern methods for estimation of ionization constants of organic compounds in solution

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