Azonine, a “Nearly” Forgotten Aromatic Molecule

Somers, Krf; Kryachko, Eugene S.; Ceulemans, Arnout

doi:10.1021/jp037046+

Cited by 7 publications

(4 citation statements)

References 34 publications

(64 reference statements)

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“…The most stable configuration of protonated indole was obtained over the carbon in position 3 (C3 site). A similar configuration was obtained by Somers et al …”

Section: Resultssupporting

confidence: 86%

“…The interaction of pyridine and indole over a Lewis acid site was not computed in this work. The protonation of indole was performed over the carbon in the position 3 of the molecule (C3 site), known and checked to be the site with the highest proton affinity (PA) from all the 7 sites where the protonation is possible (PA (C3 protonation) =212.4 kcal/mol) …”

Section: Methodsmentioning

confidence: 99%

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In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

et al. 2019

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In the present work, the liquid‐solid interaction of liquid N‐heteroaromatic compounds, commonly present in the petroleum feedstocks of the refineries, with Y zeolites used as hydrocracking catalysts was followed using IR‐ATR spectroscopy. The inhibition of the zeolitic acid sites by strongly basic pyridine and weakly basic indole was highlighted using a continuous flow IR‐ATR cell. Results were assessed by Density Functional Theory calculations to compute the vibrational frequencies of pyridine and indole according to the nature of the interaction sites: silanol groups or acidic OH groups. The study points out that IR‐ATR spectroscopy opens the way for investigating the interaction modes of low vapor pressure molecules (e. g. indole) that present an inherent difficulty to be operated in the gas phase. Moreover, the IR‐ATR makes possible the analysis of the little‐explored low wavenumber zone (<800 cm−1), that presents informative vibrational modes on the adsorption mode of N‐molecules. Hence, this work points out that for pyridine, the bands at 686 and 727 cm−1 are characteristic of pyridinium species formed over zeolitic OH groups, meanwhile, the signals at 703 and 750 cm−1, are associated to pyridine in interaction with silanol groups. The IR‐ATR study reveals that indole, a weakly basic compound, can be protonated on acidic Y zeolites as unambiguously evidenced by the formation of the bands at 1617, 1608, 1543 and 705 cm−1. Findings here exposed are crucial for studying inhibitory effects exerted by weak nitrogenated compounds on acidic materials during hydrocracking processes.

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“…The most stable configuration of protonated indole was obtained over the carbon in position 3 (C3 site). A similar configuration was obtained by Somers et al …”

Section: Resultssupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

et al. 2019

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“…[15][16][17][18][19][20][21][22] Due to their physical, chemical, and biological importance, the interactions of hydrogen bond donors with benzene and with indole and its derivatives have been extensively studied both experimentally [1][2][3][5][6][7][8][9][10] and theoretically. 4,7,11,12,28,[35][36][37][38][39][40][41][42][43][44] Correlated ab initio methods such as secondorder Møller-Plesset perturbation theory (MP2) 45,46 are capable of describing this kind of π acceptor hydrogen bonding. 7,[36][37][38][39]43,47 For example, Niu and Hall concluded 17 "DFT calculations underestimate this R-agostic interaction between CpRh(CO) and CH 4 .…”

Section: Introductionmentioning

confidence: 99%

How Well Can Density Functional Methods Describe Hydrogen Bonds to π Acceptors?

2005

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We employed four newly developed density functional theory (DFT) methods for the calculation of five pi hydrogen bonding systems, namely, H2O-C6H6, NH3-C6H6, HCl-C6H6, H2O-indole, and H2O-methylindole. We report new coupled cluster calculations for HCl-C6H6 that support the experimental results of Gotch and Zwier. Using the best available theoretical and experimental results for all five systems, our calculations show that the recently proposed MPW1B95, MPWB1K, PW6B95, and PWB6K methods give accurate energetic and geometrical predictions for pi hydrogen bonding interactions, for which B3LYP fails and PW91 is less accurate. We recommend the most recent DFT method, PWB6K, for investigating larger pi hydrogen bonded systems, such as those that occur in molecular recognition, protein folding, and crystal packing.

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“…There are few experimental reports on the nine-membered monocyclic molecules in addition to the work of Anastassiou's group. Furthermore, some theoretical studies have also been carried out on oxonin, thionin, and azonin to understand their structure, reactivity and properties . Salcedo et al investigated the aromaticity of heteronins and also probed into their reactivity with the help of condensed Fukui functions (FF) derived from electronic structure calculations .…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theoretical Investigation on Influence of Heterosubstitution and Benzannelation on the Thermal 6π Electrocyclization of cis-Cyclononatetraene

Elango

Subramanian

2005

J. Phys. Chem. A

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Thermal 6pi electrocyclization of cyclononatetraene (CNT), its hetero-substituted analogues, and its benzannelated derivatives have been investigated by using the B3LYP method employing 6-31G* and 6-311+G** basis sets. The results indicate that heterosubstitution and benzannelation influence the rate of cyclization. Nucleus independent chemical shifts (NICS), conceptual density functional theory (DFT) based reactivity descriptors, group electronegativity values, and barriers to planarity provide complementary evidence for the predicted rate of cyclization. The available experimental data are in good agreement with the computed values.

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Azonine, a “Nearly” Forgotten Aromatic Molecule

Cited by 7 publications

References 34 publications

In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

How Well Can Density Functional Methods Describe Hydrogen Bonds to π Acceptors?

Density Functional Theoretical Investigation on Influence of Heterosubstitution and Benzannelation on the Thermal 6π Electrocyclization of cis-Cyclononatetraene

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