Towards physical interpretation of substituent effects: the case of meta- and para-substituted anilines

Szatyłowicz, Halina; Siodła, Tomasz; Stasyuk, Olga A.; Krygowski, Tadeusz M.

doi:10.1039/c5cp06702b

Cited by 44 publications

(77 citation statements)

References 57 publications

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“…Moreover, the cSAR approach can be applied to both, the varying substituents, [as cSAR(X)], as well as to the reaction site (or a fixed functional group in the series X-R-Y), [cSAR(Y)], and allows to estimate the regression line cSAR(Y) vs. cSAR(X). The slope of this regression describes the strength of interactions between X and Y [9,10]. It was also shown that changes in geometry of the components of the functional group Y correlate well with cSAR(Y) [12] and hence correlate also with cSAR(X) that was documented for aniline [10], nitrobenzene [13], and benzoic acid [14] substituted derivatives.…”

Section: ) Is Alwaysmentioning

confidence: 83%

“…This approach allows to determine, in an energetic scale, the nature of the interaction between substituents in disubstituted systems. It was documented that the SESE characteristic correlates well with classical substituent constants [9,10]. SESE is a descriptor of substituent electron donating/attracting properties and takes into account all interactions in the X-R-Y system.…”

Section: ) Is Alwaysmentioning

confidence: 99%

“…By definition, cSAR(X) is a sum of atomic charges at all atoms of the substituent and the ipso carbon atom [7]. This descriptor correlates well with substituent constants [7][8][9][10]. It is important to stress that the cSAR(X) approach realized by the use of different atomic charge schemes leads to the results which are, as a rule, mutually well correlated [11].…”

Section: ) Is Alwaysmentioning

confidence: 99%

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How OH and O– groups affect electronic structure of meta-substituted and para-substituted phenols and phenolates

2017

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An application of two independent quantum chemistry-based concepts, a substituent effect stabilization energy (SESE) and a charge of the substituent active region (cSAR), for describing substituent effects allows to investigate a nature of mutual interactions between substituents. The B3LYP/6-311++G(d,p) method is employed to examine changes in properties of a reaction center Y (Y = OH or O -groups) and a transmitting moiety (the benzene ring) due to substituent effects in a series of meta-X-substituted and para-X-substituted phenol and phenolate derivatives (X = NMe 2 , NH 2 , OH, OMe, CH 3 , H, F, Cl, CF 3 , CN, CHO, COCl, COMe, CONH 2 , COOH, NO 2 , NO). HOMA, NICS(1) and pEDA parameters are used to characterize π-electron delocalization of the transmitting moiety. Relations between cSAR(X) and σ constants show almost identical sensitivity of the substituent effect in meta-substituted phenol and phenolate derivatives, whereas in para-substituted analogs, different kinds of intramolecular interactions have been revealed. Due to electron attractive property of OH group in meta position, dependences of cSAR(X) on SESE show a dramatically different picture of interaction in meta-substituted phenols as compared to that found for all other series studied. Moreover, this group affects in a different way the electronattracting and electron-donating substituents in meta position. A clear substituent effect on π-electron delocalization of the benzene ring is observed only in para-substituted phenolate derivatives. The application of cSAR(X) parameter allows to estimate a difference between its value for a particular substituent in meta and para derivatives. In some cases, this difference amounts up to ∼53% of the range of cSAR(X) variability.Keywords substituent effects . electronic structure . molecular modeling . substituent effect stabilization energy . charge of the substituent active region

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Section: ) Is Alwaysmentioning

confidence: 83%

Section: ) Is Alwaysmentioning

confidence: 99%

Section: ) Is Alwaysmentioning

confidence: 99%

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How OH and O– groups affect electronic structure of meta-substituted and para-substituted phenols and phenolates

2017

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“…cSAR(X) is a sum of atomic charges of X and of the ipso atom (carbon or nitrogen in our case) to which the substituent is attached. It was shown that cSAR(X) values correlate well [15,[19][20][21][22] with the Hammett substituent constants [13]. Moreover, it was documented that cSAR of a functional group (NO and NMe 2 ) in para-substitute d d e r i v a t i v e s o f n i t r o s o b e n z e n e a n d N , Ndimethylaminebenzene nicely describes changes in the geometry in these groups [23].…”

Section: Introductionmentioning

confidence: 90%

Towards physical interpretation of substituent effects: the case of N- and C3-substituted pyrrole derivatives

et al. 2017

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Classical and reverse substituent effects were studied for pyrrole derivatives. Two extensive sets of pyrrole derivatives with NO, NO 2 , CN, CF 3 , COMe, COOH, CHO, CONH 2 , Cl, SH, SiH 3 , F, PH 2 , H, Me, OMe, OH, NH 2 , NHMe, NMe 2 , Li, BeH, BH 2 , Na, MgH, and AlH 2 substituents at N and C3 positions were taken into account. Analysis of the substituent effects was based on charges of the Substituent Active Region (cSAR). The cSAR values were obtained from atomic charges calculated within the Quantum Theory of Atoms in Molecules (QTAIM) methodology. Calculations were performed at the B3LYP/6-311++ G** level of theory. It was documented that classical substituent effect in substituted pyrroles is much greater (approximately ten times) for substituents at C3 position than at NH group. The reverse substituent effect is also greater in C3-substituted pyrroles that in N-substituted ones. As a result of observed correlations, substituent constants for some rare substituents such as Li, BeH, BH 2 , Na, MgH, and AlH 2 were evaluated.

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“…The use of the idea of cSAR(X) enables a deeper look at the substituent effects [44,45]. The application of this concept makes the comparison of group characteristics available and easier to …”

Section: Consequences Of the Nitro Group Rotation In P-nitroanilinementioning

confidence: 99%

Effect of Intra- and Intermolecular Interactions on the Properties of para-Substituted Nitrobenzene Derivatives

et al. 2016

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Abstract:To study the influence of intra-and intermolecular interactions on properties of the nitro group in para-substituted nitrobenzene derivatives, two sources of data were used: (i) Cambridge Structural Database and (ii) quantum chemistry modeling. In the latter case, "pure" intramolecular interactions were simulated by gradual rotation of the nitro group in para-nitroaniline, whereas H-bond formation at the amino group allowed the intermolecular interactions to be accounted for. BLYP functional with dispersion correction and TZ2P basis set (ADF program) were used to perform all calculations. It was found that properties of the nitro group dramatically depend on both its orientation with respect to the benzene ring as well as on the substituent in the para-position. The nitro group lies in the plane of the benzene ring for only a small number of molecules, whereas the mean value of the twist angle is 7.3 deg, mostly due to intermolecular interactions in the crystals. This distortion from planarity and the nature of para-substituent influence the aromaticity of the ring (described by HOMA index) and properties of the nitro group due to electronic effects. The results obtained by QM calculations fully coincide with observations found for the data set of crystal structures.

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Towards physical interpretation of substituent effects: the case of meta- and para-substituted anilines

Cited by 44 publications

References 57 publications

How OH and O– groups affect electronic structure of meta-substituted and para-substituted phenols and phenolates

How OH and O– groups affect electronic structure of meta-substituted and para-substituted phenols and phenolates

Towards physical interpretation of substituent effects: the case of N- and C3-substituted pyrrole derivatives

Effect of Intra- and Intermolecular Interactions on the Properties of para-Substituted Nitrobenzene Derivatives

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