Molecular modelling studies of side-chain rotation in substituted triazine rings

Birkett, Helen E.; Cherryman, Julian C.; Chippendale, A. Margaret; Hazendonk, Paul; Harris, Robin K.

doi:10.1016/s0022-2860(01)00726-8

Cited by 15 publications

(10 citation statements)

References 52 publications

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“…Variable-temperature solution-state 13 C and 1 H NMR have amply demonstrated this order, and it is consistent with earlier work 1 on the more complicated dyestuff 1. Moreover, molecular modelling calculations 6 support this order. The low-temperature solution-state NMR spectra provided information on the populations of the various conformations.…”

Section: Discussionmentioning

confidence: 71%

“…The results of a preliminary study were presented with the initial work. 1 Rotational energy barriers calculated from an in-depth study 6 were found to be 13, 75, 91 and 91 kJ mol 1 for the˛,ˇ, and υ rotations, respectively. The internal rotations (υ, ) for the triazine side-chains have the largest energy barriers, with having the lowest.…”

Section: Introductionmentioning

confidence: 95%

“…4), suggesting that theˇrotation is now slow. A 15 N NMR spectrum of a DMSO-d 6 solution was obtained at 25°C and the assigned resonances are listed in Table 6. A single peak is observed from each type of nitrogen atom.…”

Section: Compoundmentioning

confidence: 99%

“…The effects of internal rotation have been observed in the 1 H NMR spectra of the dyestuff molecule 1 in solution in DMSO-d 6 and CD 3 OD. 1 Other groups have also reported 2 -5 exchange effects due to rotational isomerism for triazine systems.…”

Section: Introductionmentioning

confidence: 99%

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Structural investigations of three triazines: solution‐state NMR studies of internal rotation and structural information from solid‐state NMR, plus a full structure determination from powder x‐ray diffraction in one case

Birkett

Cherryman

Chippendale

et al. 2003

Magnetic Reson in Chemistry

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Three model 2,4,6-tris(amino)-1,3,5-triazines, structurally related to a dyestuff molecule previously studied by NMR, were synthesized in order to enable the effects of rotamer exchange on the NMR spectra to be investigated in more detail. Two of the compounds are novel. Internal rotation of the triazine ring substituents was studied by variable-temperature solution-state 1 H, 13 C and 15 N NMR spectroscopy. All the expected rotamers were detected for each molecule. Rotamer exchange rates varied from slow to fast over the temperature range −40 to 90• C, as observed for the dyestuff molecule itself. Solid-state 13 C and 15 N NMR provided information about the structures of the solid molecules. A full crystal structure determination from high-resolution powder x-ray diffraction was achieved for one of the molecules using simulated annealing techniques. Ab initio MO and 15 N NMR chemical shift calculations, based on energyminimized structures derived from the x-ray structure determination, enabled the effect of intermolecular hydrogen bonding on the 15 N NMR chemical shifts to be studied. The results compared favourably with the experimental solid-state 15 N NMR shifts.

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Section: Discussionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 95%

Section: Compoundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structural investigations of three triazines: solution‐state NMR studies of internal rotation and structural information from solid‐state NMR, plus a full structure determination from powder x‐ray diffraction in one case

Birkett

Cherryman

Chippendale

et al. 2003

Magnetic Reson in Chemistry

Self Cite

View full text Add to dashboard Cite

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“…Conversely, computational methods are more suitable for such studies because they can provide detailed information on the different structures and their energies along the reaction pathway 9, [13][14][15][16][17][18] . Despite these advantages, the number of computational publications including complete rotation energy profiles is rather small [2][3][4] , especially in those cases where energy profiles need to be computed along of more than one torsion angle. Furthermore, in some cases 6 the intervals of the rotation angle at which the energies are determined are so large that significant singularities of the corresponding profiles are lost, e.g.…”

Section: Introductionmentioning

confidence: 99%

Computational study of the rotational pathways of the amino group in 2-chloroaniline, azines and formamide: One or two rotational barriers?

Gálvez

Sánchez

Guirado

2015

Computational and Theoretical Chemistry

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Controlling Swing Rates in Macrocyclic Molecular Mortise Hinges

Menke,

Mellberg,

Pan

et al. 2023

Chemistry A European J

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Hinge motion is observed in macrocyclic, mortise‐type molecular hinges using variable temperature NMR spectroscopy. The data is consistent with dynamic hinging from a folded‐to‐extended‐to‐folded enantiomeric state. Crystallographic and solution structures of the folded states are reported. Chemical shift predictions derived from crystallographic data corroborate fully revolute hinge motion. The rate of hinging is affected by steric congestion at the hinge axis. A macrocycle containing glycine, 1, hinges faster than one comprising aminoisobutyric acid, 2. The free energies of activation, ΔG≠, for 1 and 2 were determined to be 13.3±0.3 kcal/mol and 16.3±0.3 kcal/mol, respectively. This barrier is largely independent of solvent across those surveyed (CD3OD, CD3CN, DMSO‐d6, pyridine‐d5, D2O). Experiment and computation predict energy barriers that are consistent with disruption of an intramolecular network of hydrogen bonds. DFT calculations reveal a pathway for hinge motion.

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Molecular modelling studies of side-chain rotation in substituted triazine rings

Cited by 15 publications

References 52 publications

Structural investigations of three triazines: solution‐state NMR studies of internal rotation and structural information from solid‐state NMR, plus a full structure determination from powder x‐ray diffraction in one case

Structural investigations of three triazines: solution‐state NMR studies of internal rotation and structural information from solid‐state NMR, plus a full structure determination from powder x‐ray diffraction in one case

Computational study of the rotational pathways of the amino group in 2-chloroaniline, azines and formamide: One or two rotational barriers?

Controlling Swing Rates in Macrocyclic Molecular Mortise Hinges

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