Substituent effects on the stability of the four most stable tautomers of adenine and purine

Szatyłowicz, Halina; Jezuita, Anna; Marek, Paulina H.; Krygowski, Tadeusz M.

doi:10.1039/c9ra04615a

Cited by 9 publications

(10 citation statements)

References 45 publications

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“…This is consistent with results for adenine based on other substituent effect descriptors. 49 As expected, cSAR(NH 2 ) values are higher in monomers (triangles) than in quartets (circles) where amino group is involved in H-bond. The reason is accumulation of negative charge on the N atom of proton-donating -NH part of the amino group during formation of hydrogen bond.…”

Section: Substituent Effect On H-bondingclassical Substituent Effectsupporting

confidence: 67%

Substituted adenine quartets: interplay between substituent effect, hydrogen bonding, and aromaticity

et al. 2020

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Section: Substituent Effect On H-bondingclassical Substituent Effectsupporting

confidence: 67%

Substituted adenine quartets: interplay between substituent effect, hydrogen bonding, and aromaticity

et al. 2020

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“…Effect of the Solvent on Tautomer Stability and Solvation Energy. As shown in a recent study on the stability of substituted (C2−X and C8−X) adenine amino tautomers in the gas phase, 76 substituted 9H tautomers are the most stable, whereas 1H are the least stable. As for the 7H and 3H systems, they display stability between 9H and 1H, but their mutual stability varies depending on the substituent and its position.…”

Section: ■ Results and Discussionmentioning

confidence: 80%

Effect of the Solvent and Substituent on Tautomeric Preferences of Amine-Adenine Tautomers

et al. 2021

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Adenine is one of the basic molecules of life; it is also an important building block in the synthesis of new pharmaceuticals, electrochemical (bio)sensors, or self-assembling molecular materials. Therefore, it is important to know the effects of the solvent and substituent on the electronic structure of adenine tautomers and their stability. The four most stable adenine amino tautomers (9H, 7H, 3H, and 1H), modified by substitution (C2– or C8−) of electron-withdrawing NO2 and electron-donating NH2 groups, are studied theoretically in the gas phase and in solvents of different polarities (1 ≤ ε < 109). Solvents have been modeled using the polarizable continuum model. Comparison of the stability of substituted adenine tautomers in various solvents shows that substitution can change tautomeric preferences with respect to the unsubstituted adenine. Moreover, C8 substitution results in slight energy differences between tautomers in polar solvents (<1 kcal/mol), which suggests that in aqueous solution, C8–X-substituted adenine systems may consist of a considerable amount of two tautomers9H and 7H for X = NH2 and 3H and 9H for X = NO2. Furthermore, solvation enhances the effect of the nitro group; however, the enhancement strongly depends on the proximity effects. This enhancement for the NO2 group with two repulsive N···ON contacts can be threefold higher than that for the NO2 with one attractive NH···ON contact. The proximity effects are even more significant for the NH2 group, as the solvation may increase or decrease its electron-donating ability, depending on the type of proximity.

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“…Furthermore, the substituent effect of the nitro group in various positions (C2-, C8-, and N-) of adenine and purine tautomers was also investigated [121]. The obtained SESE values (relative to purine, SESE PU ) for nitro and amine derivatives are shown in Table 11.…”

Section: •••Hf H•••fh N•••hf and Nh•••f −mentioning

confidence: 99%

Substituent effects of nitro group in cyclic compounds

2020

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Numerous studies on nitro group properties are associated with its high electron-withdrawing ability, by means of both resonance and inductive effect. The substituent effect of the nitro group may be well described using either traditional substituent constants or characteristics based on quantum chemistry, i.e., cSAR, SESE, and pEDA/sEDA models. Interestingly, the cSAR descriptor allows to describe the electron-attracting properties of the nitro group regardless of the position and the type of system. Analysis of classical and reverse substituent effects of the nitro group in various systems indicates strong pi-electron interactions with electron-donating substituents due to the resonance effect. This significantly affects the pi-electron delocalization of the aromatic ring decreasing the aromatic character, evidenced clearly by HOMA values. Use of the pEDA/sEDA model allows to measure the population of electrons transferred from the ring to the nitro group. Keywords Nitro group. Substituent effects. Molecular modeling. Sigma and pi electron structure. Substituent effect stabilization energy. Charge of the substituent active region This review is dedicated to our friend and mentor Professor Tadeusz Marek Krygowski of the Department of Chemistry of the Warsaw University in gratitude for his guidance, support, and engagement in our research.

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Substituent effects on the stability of the four most stable tautomers of adenine and purine

Abstract: Substituent effects at the C2-, C8- and N-positions of adenine and purine in their four the most stable tautomers are examined using substituents of varying electronic properties: NO2, CN, CHO, Cl, F, H, Me, OMe, OH and NH2.

Cited by 9 publications

References 45 publications

Substituted adenine quartets: interplay between substituent effect, hydrogen bonding, and aromaticity

Substituted adenine quartets: interplay between substituent effect, hydrogen bonding, and aromaticity

Effect of the Solvent and Substituent on Tautomeric Preferences of Amine-Adenine Tautomers

Substituent effects of nitro group in cyclic compounds

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