Heterochiral
Paired Concept:
Homochiral
Definition: Describing a molecular system, assembly, crystal, material, or mixture containing both enantiomeric forms, or chiral components of opposite handedness.
Context: Heterochirality represents the coexistence of opposite stereochemical forms within the same system. In chemistry, heterochiral arrangements may exhibit distinct thermodynamic stability, crystal packing, supramolecular organization, and biological behavior compared with corresponding homochiral systems. In supramolecular chemistry and crystallography, heterochiral assemblies often compete with homochiral assemblies, and the balance between them can strongly influence material properties. In biological systems, heterochiral combinations are generally uncommon but can occur in specialized circumstances, such as D-amino acids in bacterial cell walls or synthetic peptide systems.
Example: A racemic crystal containing both R- and S-enantiomers in the same crystal lattice is a heterochiral assembly, A peptide containing both L- and D-amino acids is a heterochiral peptide.
Related Terms: Homochiral; Racemate; Scalemic Mixture; Mirror-Image Biology; Chiral Materials
Reference: Eliel, E. L.; Wilen, S. H. Stereochemistry of Organic Compounds. Wiley, New York (1994).
