Substituent effects on the stability of the four most stable tautomers of adenine and purine. Issue 54 (2nd October 2019)

• Record Type: Journal Article
• Authors: Szatylowicz, Halina; Jezuita, Anna; Marek, Paulina H.; Krygowski, Tadeusz M.
• Is Part Of: RSC advances. Volume 9:Issue 54(2019)
• Page Start: 31343
• Page End: 31356
• Publication Date: 2019-10-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9ra04615a
• Languages: English
• ISSNs: 2046-2069

Abstract

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 . Abstract : Substituent effects at the C2-, C8- and N-positions of adenine and purine in their four the most stable tautomers are studied by means of B97D3/aug-cc-pvdz computation applying substituents of varying electronic properties: NO2, CN, CHO, Cl, F, H, Me, OMe, OH and NH2 . The substituent effect is characterized by the substituent effect stabilization energy (SESE) and substituent Hammett constant σ . For adenine, SESE is obtained with purine as the reference system. Additionally, for both adenine and purine, SESE characteristics are estimated with benzene, imidazole and amino-pyrimidine as reference systems, when possible, taking into account substitution in topologically equivalent positions. The role of a C6–NH2 group in adenine in modifying the substitution effect is observed and discussed. Additionally, the proximity effect for some asymmetric substituents ( e.g. CHO, OMe) is recognized and meticulously analyzed.