✦ LIBER ✦

Empirical force field calculations VIII The interconversion of all-cis-1,2,3,4,5,6-hexamethylcyclohexane

✍ Scribed by B. van de Graaf; J. M. A. Baas; H. A. Widya

Book ID: 104588297
Publisher: Elsevier Science
Year: 2010
Tongue: English
Weight: 257 KB
Volume: 100
Category: Article
ISSN: 0165-0513
DOI: 10.1002/recl.19811000205

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The calculation of the enthalpy of activation for the interconversion of the equi‐energetic chair conformers of all‐cis‐1,2,3,4,5,6‐hexamethylcyclohexane (1), using five empirical force fields, gives rather poor results. A sizable negative entropy of activation, indicated by the calculations, can only partly compensate for the differences between experimental and calculated values of the free enthalpy of activation. Comparison of individual strain components with similar data for cyclohexane indicates the importance of the non‐bonded interactions for the interconversion barrier. The barriers for the chair‐chair interconversions of cyclohexane and 1 should be included in future force field parametrizations.

📜 SIMILAR VOLUMES

Empirical Force Field Calculations XIII.

Empirical Force Field Calculations XIII. The Ring Interconversion Modes of cis-1, 2, 3, 4, 4a, 5, 8, 8a-Octahydronaphthalene and its 1α, 4α-Dimethyl Derivative

✍ P. Vanhee; D. Tavernier; J. M. A. Baas; B. van De Graaf 📂 Article 📅 2010 🏛 Wiley (John Wiley & Sons) ⚖ 412 KB 👁 1 views

Empirical force field calculations—V: Bi

Empirical force field calculations—V: Bicyclo[2.2.0]hexane and its seven 1,2,3,4,5,6-hexamethyl derivatives

✍ J.M.A. Baas; B. Van De Graaf; F. Van Rantwijk; A. Van Veen 📂 Article 📅 1979 🏛 Elsevier Science 🌐 French ⚖ 180 KB

Empirical force field calculations XXI.

Empirical force field calculations XXI. The ring inversion of cis-transoid-cis-1,4,4a,5,8,8a,9,9a,10,10a-decahydroanthracene

✍ D. Tavernier; J. M. A. Baas; B. van de Graa; P. Vanhee 📂 Article 📅 2010 🏛 Elsevier Science 🌐 English ⚖ 356 KB

Empirical force field calculations. 20.

Empirical force field calculations. 20. Routes in the inversion of cis-transoid-cis- and of cis-cisoid-cis-perhydroanthracene

✍ Vanhee, Paul; Van de Graaf, Bastiaan; Tavernier, Dirk; Baas, Jan M. A. 📂 Article 📅 1983 🏛 American Chemical Society 🌐 English ⚖ 617 KB

Empirical force field calculations VI: E

Empirical force field calculations VI: Exploration of reaction paths for the interconversion of conformers. Application to the interconversion of the cyclohexane conformers

✍ B. van de Graaf; J. M. A. Baas; A. van Veen 📂 Article 📅 2010 🏛 Elsevier Science 🌐 English ⚖ 424 KB

## Abstract A method is described for the calculation of reaction paths for the interconversion of conformers by forcing the internal rotation around one or more single bonds. The implementation of the method in a general computer program for molecular mechanics is discussed. It is shown that forci

A Perturbational Force Field Calculation

A Perturbational Force Field Calculation Explains the Increased Conformational Inversion Barrier of 1α,4α-Dihydroxy-cis-1,2,3,4,4a,5,8,8a-Octahydronaphthalene

✍ P. Vanhee; D. Tavernier 📂 Article 📅 2010 🏛 Wiley (John Wiley & Sons) ⚖ 320 KB

4 4 . 7 kJ mol-1 ( K = 0 . 5 ) . hydrocarbon. This increase is rationalized by a perturbational force field study. The reliability of the perturbational calculation was tested by a comparison of calculated and experimental conformational equilibria in various 1and 2-oxygenated \*-decalins. The Gibb