Sterically crowded five-membered heterocyclic systems. Part 2. Conformation of 2,2,5,5-tetramethylpyrrolidin-3-ol from nuclear magnetic resonance spectroscopy, crystal structure, and molecular mechanics calculations

The most probable time‐averaged conformations of three polyammonium cations Hn2n+ (n = 3–5) formed from the macrocyclic pentamine ligand (2, scorpiand) [derivative of 1,4,8,11‐tetraazacyclotetradecane (cyclam)] were analyzed in order to elucidate an origin of ‘wrong‐way’ amine‐protonation shifts found in some 13C NMR pH‐profiles determined for the acidic H2O/D2O solution. These NMR trends were reproduced quite well in δCs computed for multicomponent shapes of related cations, which were in turn elucidated by the best fitting experimental data to those predicted by the gauge‐independent atomic orbital (GIAO) B3LYP/6‐31G* method, including the IEF‐PCM approach. A consistent DFT methodology of the treatment of such equilibrated cationic mixtures is proposed. Moreover, a few novel ONIOM2‐GIAO B3LYP/6‐31G*:STO‐3G type supermolecular calculations were performed for a simulated presence of bulk water molecules surrounding H525+. Copyright © 2009 John Wiley & Sons, Ltd.

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Three-component conformational equilibria of some flexible pyrrolidin-2-(thi)ones in solution by NMR data (δC, δH, and nJHH) and their DFT predictions: a confrontation of different approaches

Nazarski

Pasternak

Leśniak

2011

Tetrahedron

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Sterically crowded five-membered heterocyclic systems. Part 2. Conformation of 2,2,5,5-tetramethylpyrrolidin-3-ol from nuclear magnetic resonance spectroscopy, crystal structure, and molecular mechanics calculations

Cited by 5 publications

References 2 publications

ChemInform Abstract: Sterically Crowded Five‐membered Heterocyclic Systems. Part 2.

ChemInform Abstract: Sterically Crowded Five‐membered Heterocyclic Systems. Part 2.

Physical image versus structure relation. Part 14—an attempt to rationalize some acidic region ¹³C NMR‐pH titration shifts for tetraaza macrocycles throughout the conformational GIAO DFT computational results: a pendant‐arm cyclam case

Three-component conformational equilibria of some flexible pyrrolidin-2-(thi)ones in solution by NMR data (δC, δH, and nJHH) and their DFT predictions: a confrontation of different approaches

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Sterically crowded five-membered heterocyclic systems. Part 2. Conformation of 2,2,5,5-tetramethylpyrrolidin-3-ol from nuclear magnetic resonance spectroscopy, crystal structure, and molecular mechanics calculations

Cited by 5 publications

References 2 publications

ChemInform Abstract: Sterically Crowded Five‐membered Heterocyclic Systems. Part 2.

ChemInform Abstract: Sterically Crowded Five‐membered Heterocyclic Systems. Part 2.

Physical image versus structure relation. Part 14—an attempt to rationalize some acidic region 13C NMR‐pH titration shifts for tetraaza macrocycles throughout the conformational GIAO DFT computational results: a pendant‐arm cyclam case

Three-component conformational equilibria of some flexible pyrrolidin-2-(thi)ones in solution by NMR data (δC, δH, and nJHH) and their DFT predictions: a confrontation of different approaches

Contact Info

Product

Resources

About

Physical image versus structure relation. Part 14—an attempt to rationalize some acidic region ¹³C NMR‐pH titration shifts for tetraaza macrocycles throughout the conformational GIAO DFT computational results: a pendant‐arm cyclam case