Hierarchy of Times for Forming the System of Chiral Phases in Solutions of Trifluoroacetylated Amino Alcohols

Resumo

It has been experimentally established that the chiroptical characteristics of freshly prepared solutions of trifluoroacetylated amino alcohols (TFAAAs) evolve before reaching equilibrium. The evolution can be monotone or quasi-oscillatory. The latter reflects the formation of successive levels of the hierarchy of chiral phases with an alternating sign of chirality in the solution. The fast (the characteristic time τ from ~30 s to ~30 min) and slow (τ ~ 1–3 h) stages of evolution have been experimentally revealed. It is shown via calculation that the fast stage corresponds to the early stages of the formation of the supramolecular structure of the solutions of TFAAAs, namely, the growth of strings with diameters from several nanometers to tenths of a micrometer, while the slow stage corresponds to the late stages in the formation of the structure of the solutions, namely, the growth of strings with diameters from tenths of a micrometer up to several micrometers.