C. Altona, H. Buys, E. Havinga
Sep 2, 2010
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0
Influential Citations
14
Citations
Journal
Recueil des Travaux Chimiques des Pays-Bas
Abstract
The dipole moments and NMR spectra of trans-1,2-dichloro- (I), trans-1,2-bromochloro- (II), trans-1,2-dibromo- (III) and trans-1,2-dibromo-1-methylcyclopentane (IV) in several solvents are reported. Special attention is given to the separation of the outer peaks in the low-field part of the NMR spectra, due to the protons in the CHX-moiety. This separation is equal to JAX + JBX and is shown to be correlated linearly with the square of the electric moment. It is proposed that the conformational properties of these molecules be described in terms of a solvent-dependent dynamic equilibrium aa ⇌ ee, with the diaxial conformation predominating even in a highly polar solvent. Each of the two conformers may correspond to the half-chair or the envelope model with the halogen atoms in the most puckered part of the ring. A limited pseudolibration about these forms is possible.