Wydział Chemii

Katarzyna Ślepokura

Tomasz Koźlecki

Tadeusz Lis

2003

Journal of Molecular Structure

647

223-231

10.1016/S0022-2860(02)00529-X

Naukowa

Angielski

Artykuł

The crystal and molecular structures of the cis- and trans-isomers of 2,5-diethoxy-2,5-bis(hydroxymethyl)-[1,4]-dioxane have been determined by X-ray analysis. The cis- (I) and trans-isomers (II) crystallize in the monoclinic (space group P2₁/c) and orthorhombic (Pbca) system, respectively. The [1,4]-dioxane ring of the cis-isomer molecule adopts a twist-boat conformation, while the ring of the trans-isomer is a chair. The two ethoxy groups in II are in more crowded axial positions, due to the anomeric effect. The anomeric effect, stronger in the cis-isomer, influences its stability, despite the presence of two bulky hydroxymethyl groups in the equatorial orientation and the low-energy chair conformation of the trans-isomer. Both hydroxyl groups in I and II act as donors in intermolecular two-centre and three-centre O–H⋯O hydrogen bonding, which may be classified as medium strong and weak. Additionally, there are C–H⋯O hydrogen interactions in each crystal; that in the cis-isomer is intramolecular.

Twist-boat conformation, [1, 4]-Dioxane ring, Intermolecular hydrogen bonds, Three-centre hydrogen bonds, Weak C–H⋯O intermolecular contacts

https://doi.org/10.1016/S0022-2860(02)00529-X

http://www.elsevier.com