Matches in SemOpenAlex for { <https://semopenalex.org/work/W4220679782> ?p ?o ?g. }
- W4220679782 endingPage "1937" @default.
- W4220679782 startingPage "1937" @default.
- W4220679782 abstract "High level DLPNO−CCSD(T) electronic structure calculations with extended basis sets over B3LYP−D3 optimized geometries indicate that the three methyl groups in caffeine overcome steric hindrance to adopt uncommon conformations, each one placing a C−H bond on the same plane of the aromatic system, leading to the C−H bonds eclipsing one carbonyl group, one heavily delocalized C−N bond constituent of the fused double ring aromatic system, and one C−H bond from the imidazole ring. Deletion of indiscriminate and selective non-Lewis orbitals unequivocally show that hyperconjugation in the form of a bidirectional −CH3 ⇆ aromatic system charge transfer is responsible for these puzzling conformations. The structural preferences in caffeine are exclusively determined by orbital interactions, ruling out electrostatics, induction, bond critical points, and density redistribution because the steric effect, the allylic effect, the Quantum Theory of Atoms in Molecules (QTAIM), and the non-covalent interactions (NCI), all predict wrong energetic orderings. Tiny rotational barriers, not exceeding 1.3 kcal/mol suggest that at room conditions, each methyl group either acts as a free rotor or adopts fluxional behavior, thus preventing accurate determination of their conformations. In this context, our results supersede current experimental ambiguity in the assignation of methyl conformation in caffeine and, more generally, in methylated xanthines and their derivatives." @default.
- W4220679782 created "2022-04-03" @default.
- W4220679782 creator A5022744060 @default.
- W4220679782 creator A5062905088 @default.
- W4220679782 creator A5074855295 @default.
- W4220679782 date "2022-03-17" @default.
- W4220679782 modified "2023-09-30" @default.
- W4220679782 title "Analysis of Conformational Preferences in Caffeine" @default.
- W4220679782 cites W1574356778 @default.
- W4220679782 cites W1874851667 @default.
- W4220679782 cites W1966949133 @default.
- W4220679782 cites W1976774792 @default.
- W4220679782 cites W1977963949 @default.
- W4220679782 cites W1990484210 @default.
- W4220679782 cites W2000325962 @default.
- W4220679782 cites W2004226047 @default.
- W4220679782 cites W2004627045 @default.
- W4220679782 cites W2008382162 @default.
- W4220679782 cites W2012162376 @default.
- W4220679782 cites W2016374980 @default.
- W4220679782 cites W2018674598 @default.
- W4220679782 cites W2025358370 @default.
- W4220679782 cites W2025669771 @default.
- W4220679782 cites W2038767330 @default.
- W4220679782 cites W2039424625 @default.
- W4220679782 cites W2043487512 @default.
- W4220679782 cites W2059156553 @default.
- W4220679782 cites W2064659572 @default.
- W4220679782 cites W2067718414 @default.
- W4220679782 cites W2073239074 @default.
- W4220679782 cites W2078511427 @default.
- W4220679782 cites W2079488969 @default.
- W4220679782 cites W2082997006 @default.
- W4220679782 cites W2085966856 @default.
- W4220679782 cites W2086803729 @default.
- W4220679782 cites W2093420297 @default.
- W4220679782 cites W2098212420 @default.
- W4220679782 cites W2104919283 @default.
- W4220679782 cites W2106462593 @default.
- W4220679782 cites W2107826009 @default.
- W4220679782 cites W2107959691 @default.
- W4220679782 cites W2120114161 @default.
- W4220679782 cites W2127932543 @default.
- W4220679782 cites W2158040090 @default.
- W4220679782 cites W2298079105 @default.
- W4220679782 cites W2308033060 @default.
- W4220679782 cites W2319811184 @default.
- W4220679782 cites W2320548800 @default.
- W4220679782 cites W2471170444 @default.
- W4220679782 cites W2486822725 @default.
- W4220679782 cites W2740009439 @default.
- W4220679782 cites W2744105981 @default.
- W4220679782 cites W2782702826 @default.
- W4220679782 cites W2789748465 @default.
- W4220679782 cites W2793553054 @default.
- W4220679782 cites W2883047830 @default.
- W4220679782 cites W2891416510 @default.
- W4220679782 cites W2899478196 @default.
- W4220679782 cites W2908185037 @default.
- W4220679782 cites W2914595807 @default.
- W4220679782 cites W2949469645 @default.
- W4220679782 cites W2951951611 @default.
- W4220679782 cites W2968147423 @default.
- W4220679782 cites W2973539790 @default.
- W4220679782 cites W2981067428 @default.
- W4220679782 cites W2993481160 @default.
- W4220679782 cites W2999182595 @default.
- W4220679782 cites W3006641532 @default.
- W4220679782 cites W3006659386 @default.
- W4220679782 cites W3014674543 @default.
- W4220679782 cites W3015638320 @default.
- W4220679782 cites W3027753579 @default.
- W4220679782 cites W3087968175 @default.
- W4220679782 cites W3094693354 @default.
- W4220679782 cites W3121033517 @default.
- W4220679782 cites W3127021009 @default.
- W4220679782 cites W3134980746 @default.
- W4220679782 cites W3162501117 @default.
- W4220679782 cites W3166725674 @default.
- W4220679782 cites W3176176573 @default.
- W4220679782 cites W3193451618 @default.
- W4220679782 cites W3198720977 @default.
- W4220679782 cites W3201469229 @default.
- W4220679782 cites W3201602869 @default.
- W4220679782 cites W815967262 @default.
- W4220679782 cites W3083429570 @default.
- W4220679782 doi "https://doi.org/10.3390/molecules27061937" @default.
- W4220679782 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/35335301" @default.
- W4220679782 hasPublicationYear "2022" @default.
- W4220679782 type Work @default.
- W4220679782 citedByCount "1" @default.
- W4220679782 countsByYear W42206797822022 @default.
- W4220679782 crossrefType "journal-article" @default.
- W4220679782 hasAuthorship W4220679782A5022744060 @default.
- W4220679782 hasAuthorship W4220679782A5062905088 @default.
- W4220679782 hasAuthorship W4220679782A5074855295 @default.
- W4220679782 hasBestOaLocation W42206797821 @default.
- W4220679782 hasConcept C130188946 @default.