Electrostatic chiral distinction: tetrahedral model dimers.
Although chiral distinction plays a pervasive role in chemistry, a complete understanding of how this takes place is still lacking. In this work, we expand the earlier described minimal requirement of so called four-point interactions (vide infra). We focus on chiral point charge model systems as a means to aid in the dissection of the underlying, operative principles. We also construct models with defined symmetry characteristics. By considering extensive constellations of diastereomeric complexes, we are able to identify emerging principles for chiral distinction. As previously postulated, all the diastereomeric complexes, regardless of their nominal contact-points, possess a chiral distinction energy. In the comparison of complexes, we find that, contrary to chemical intuition, the magnitude of chiral distinction does not correlate with the stability of the complexes, i.e., consideration of low energy complexes may not be an effective way to evaluate chiral distinction. Similarly, we do not find a correlation between the number of contact-points and chiral distinction. Moreover, favorable interactions and facile chiral distinction appear to be unrelated. We also see some tendency for greater chiral distinction in less symmetric systems, although this may not be general. These studies can now form the basis to fold in higher levels of complexity into the models so as to gain further insights into the nature of chiral distinction.
Garten
Sarit
S
Department of Organic Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
Biedermann
P Ulrich
PU
Topiol
Sid
S
Agranat
Israel
I
D019281:Dimerization; D006846:Hydrocarbons, Halogenated / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D055672:Static Electricity; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics
D006846:Hydrocarbons, Halogenated; C424690:bromochlorofluoromethane