Accessing Centnerszwer's quasiracemate – molecular shape controlled molecular recognition

Abstract

Reinvestigation of M. Centnerszwer's 1899 quasiracemate using tailor-made additives offers important insight to molecular shape directed supramolecular assemblies.

Polymorphism of the quasiracemate d-2-aminobutyric acid:l-norvaline

“…1 Generally, their structures are similar to their purely racemic counterparts, often displaying pseudo-inversion symmetry, and can therefore be used to investigate the influence of molecular shape on crystal structures and molecular alignment. [2][3][4] In the case of amino acids, many quasiracemates have been found by Görbitz et al over the past 18 years. 1,[5][6][7][8][9][10] Most of the linear aliphatic chain quasiracemates consist of bilayers interconnected by an LD-LD hydrogen bonding pattern.…”

Dual space divergence in small molecule quasiracemates: benzoyl leucine and phenylalanine assemblies

“…The challenge arises in the design stage, where the inherent flexibility of the term quasiracemate -equimolar ratios of chemically unique compounds of opposite handedness -intentionally lacks details of the chemical frameworks, functional groups and structural difference limitations needed for successful quasiracemate formation. Literature reports suggest that the structural variation between small molecule quasienantiomers occurs at only one site with a relatively minor imposed structural difference -e.g., Cl/Br [21][22][23][24][25] and CH 3 /Cl 21,23,26 represent common pairings. Though this strategy continues to show success with quasiracemate assembly, it also presents questions relating to a broader understanding of the term quasiracemate and the degree of structural tolerance permitted during quasiracemate assembly.…”

“…Literature reports suggest that the structural variation between small molecule quasienantiomers occurs at only one site with a relatively minor imposed structural difference – e.g. , Cl/Br 21–25 and CH 3 /Cl 21,23,26 represent common pairings. Though this strategy continues to show success with quasiracemate assembly, it also presents questions relating to a broader understanding of the term quasiracemate and the degree of structural tolerance permitted during quasiracemate assembly.…”