Molecular structure of carphedon as studied by gas electron diffraction and quantum chemical calculations

Ksenafontov, Denis N.; Moiseeva, Natalia F.; Rykov, Anatolii N.; Shishkov, Igor F.; Oberhammer, Heinz

doi:10.1007/s11224-012-0039-6

Cited by 3 publications

(1 citation statement)

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“…In routine GED studies this problem is usually not discussed. Instead, it is assumed that the total error can be represented as a range of parameter values, which is calculated as standard deviation, sometimes multiplied by a factor from 1 to 3. − Additionally, a so-called scale error is included in the case of bond lengths and mean square amplitudes of interatomic vibrations. Most often it is calculated to be 0.1–0.2% of the parameter value. , The disadvantage of this simple approach is that it does not account for other sources of errors like constraints or restraints, uncertainty in models, or background lines.…”

Section: Introductionmentioning

confidence: 99%

Conformational and Bonding Properties of 3,3-Dimethyl- and 6,6-Dimethyl-1,5-diazabicyclo[3.1.0]hexane: A Case Study Employing the Monte Carlo Method in Gas Electron Diffraction

et al. 2015

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Gas-phase structures of two isomers of dimethyl-substituted 1,5-diazabicyclo[3.1.0]hexanes, namely, 3,3-dimethyl- and 6,6-dimethyl-1,5-diazabicyclo[3.1.0]hexane molecules, have been determined by gas electron diffraction method. A new approach based on the Monte Carlo method has been developed and used for the analysis of precision and accuracy of the refined structures. It was found that at 57 °C 3,3-dimethyl derivative exists as a mixture of chair and boat conformers with abundances 68(8)% and 32(8)%, respectively. 6,6-Dimethyl-1,5-diazabicyclo[3.1.0]hexane at 50 °C has only one stable conformation with planar 5-ring within error limits. Theoretical calculations predict that the 6,6-dimethyl isomer is more stable in comparison to the 3,3-dimethyl isomer with energy difference 3-5 kcal mol(-1). In order to explain the relative stability and bonding properties of different structures the natural bond orbitals (NBO), atoms in molecules (AIM), and interacting quantum atoms (IQA) analyses were performed.

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