Wydział Chemii

Katarzyna Ślepokura

Tadeusz Lis

2004

Carbohydrate Research

339

1995-2007

10.1016/j.carres.2004.05.020

Naukowa

Angielski

Artykuł

The crystal and molecular structures of three crystalline forms of the dihydroxyacetone dimer, C₆H₁₂O₆, DHA-dimer: α (1a), β (1b), and γ (1c), the hydrated calcium chloride complex of dihydroxyacetone monomer, CaCl₂(C₃H₆O₃)₂·H₂O, CaCl₂(DHA)₂·H₂O (2a), the tetrahydrated calcium chloride complex of dihydroxyacetone monomer, CaCl₂(C₃H₆O₃)·4H₂O, CaCl₂(DHA)·4H₂O (2b), the dihydroxyacetone monomer, C₃H₆O₃, DHA (2c), and dihydroxyacetone dimethyl acetal, C₅H₁₂O₄, (MeO)₂DHA (3) are described. Compounds 1a and 2b crystallize in the triclinic system, and 1b,c, 2a,c, and 3 are monoclinic. Molecules of all forms of dihydroxyacetone dimer 1a,b, and 1c are the trans isomers, with the 1,4-dioxane ring in the chair conformation and the hydroxyl and hydroxymethyl groups in axial and equatorial dispositions, respectively. The Ca²⁺ ions in 2a and 2b are bridged by the carbonyl O atoms from two symmetry-related DHA molecules to form centrosymmetric dimers with Ca⋯Ca distance of 4.307(2) Å in 2a and 4.330(2) and 4.305(2) Å in two crystallographically independent dimers in 2b. DHA molecules coordinate to the Ca²⁺ ions by hydroxyl and carbonyl oxygen atoms. The eight-coordinate polyhedra of Ca²⁺ are completed by water molecule and Cl⁻ ion in 2a and by four water molecules in 2b. The dihydroxyacetone molecules in 2a,b, and 2c are in an extended conformation, with both hydroxyl groups being synperiplanar (sp) to the carbonyl O atom. All hydroxyl groups in 2c (along with water molecules in 2a and 2b) are involved as donors in medium strong and weak intermolecular O–H⋯O hydrogen bonding. Some of them, as well as carbonyl O atoms or Cl⁻ ions in 2a and 2b, act as acceptors in C–H⋯O (and C–H⋯Cl) hydrogen interactions.

Sugars, Ketotriose, Dihydroxyacetone, DHA, Dihydroxyacetone dimer, Ca coordination, O–H⋯O hydrogen bonds, O–H⋯Cl hydrogen bonds

https://doi.org/10.1016/j.carres.2004.05.020

http://www.elsevier.com