[Zurück]

V. Savic, F. Eder, C. Göb, M.D. Mihovilovic, C. Stanetty, B. Stöger:
"The role of hydrogen bonding in the incommensurate modulation of myo-inositol camphor ketal";
Acta Crystallographica Section B, 77 (2021), S. 83 - 92.

myo-Inositol-2,3-d-camphor ketal crystallizes as an incommensurate structure with the C2(0σ₂1/2) superspace group symmetry [σ₂ = 0.1486 (3) at 100 K]. The bornane and myo-inositol moieties aggregate in distinct layers extending parallel to (001). The myo-inositol rings are connected by a complex hydrogen-bonding network extending in two dimensions, which is disordered in the basic structure and (mostly) ordered in the actual modulated structure. The domains of definition of the H atoms in internal space were derived by chemical reasoning and modeled with crenel functions. By tracing the hydrogen bonding, distinct chains, which are periodic in the [100] direction, are identified. These chains possess one of two possible orientations with respect to the hydrogen bonding. The incommensurate modulation is characterized by a non-periodic succession of the two chain orientations in the [010] direction. On heating, the σ₂-component of the modulation wave vector decreases from σ₂ = 0.1486 (3) at 100 K to σ₂ = 0.1405 (6) at 430 K, which means that the periodicity of the modulation wave increases. No order-disorder phase transition was evidenced up to the melting point (with decomposition).

incommensurate modulation; hydrogen bonding; X-ray diffraction; sugar chemistry

http://dx.doi.org/10.1107/S2052520620015929