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Interpretation of substituent effects on 13C and 15N NMR chemical shifts in 6-substituted purines
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SYSNO ASEP 0369914 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Interpretation of substituent effects on 13C and 15N NMR chemical shifts in 6-substituted purines Author(s) Standara, Stanislav (UOCHB-X)
Bouzková, K. (CZ)
Straka, Michal (UOCHB-X) RID, ORCID
Zacharová, Z. (CZ)
Hocek, Michal (UOCHB-X) RID, ORCID
Marek, J. (CZ)
Marek, R. (CZ)Number of authors 7 Source Title Physical Chemistry Chemical Physics. - : Royal Society of Chemistry - ISSN 1463-9076
Roč. 13, č. 35 (2011), s. 15854-15864Number of pages 11 s. Language eng - English Country GB - United Kingdom Keywords purine ; nuclear magnetic shielding ; localized molecular orbitals ; conformational dependence Subject RIV CC - Organic Chemistry R&D Projects GA203/09/2037 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z40550506 - UOCHB-X (2005-2011) UT WOS 000294167700016 DOI 10.1039/c1cp20680j Annotation The present work aims to analyze the effects of substituents on the electron distribution in the purine core as reflected by NMR chemical shifts. We collected a comprehensive set of experimental NMR data for a variety of 6-substituted purines and determined the molecular and crystal structures of three derivatives by X-ray diffraction. The density-functional methods have been employed to enable understanding of the substituent-induced changes in the NMR chemical shifts of the atoms in the purine skeleton. Analyses of the nuclear shielding using localized molecular orbitals (LMOs) were used to break down the values of the isotropic 13C and 15N NMR chemical shifts and the chemical shift tensors into the contributions of the individual LMOs. The experimental and calculated trends in the chemical shift of the N-3 atom correlate nicely with the Hammett constants and the calculated natural charges on N-3, whereas the contributions of the LMOs to the N-1 and C-6 chemical shifts are found to be more complex. Workplace Institute of Organic Chemistry and Biochemistry Contact asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Viktorie Chládková, Tel.: 232 002 434 Year of Publishing 2012
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