Preferred mirror image recognition in the solid is not limited only to single component crystals but rather extends to closely related compounds of opposite chirality, so-called quasiracemates. During the cocrystallization experiment the `almost’ enantiomeric molecules seif-organize and, with their alternating arrangement of left and right handed enantiomers, often mimic one of the racemic parent structures, crystallizing in an acentric subgroup of the latter. Their arrangement may imply pseudo inversion between chemically different nearest neighbours of opposite chirality and therefore the formation of pairs of molecules with a resulting non-zero dipole moment. I try to exploit the statistical preference for heterochiral crystals as a design tool to generate predictable molecular assemblies. The present work leads the way to the Synthesis and characterization of binary crystals built up from square-planar complexes. As part of my effort to understand the factors that influence quasiracemate formation I have designed, synthesized and crystallographically characterized Sets of ortho-metallated complexes of different chirality that form approximately centrosymmetric patterns. X-ray studier of the enantiomeric, racemic and quasiracemic crystal structures provide evidence of the role of molecular topology to quasiracemate formation and contributes to the knowledge bare of exploitable molecular features for the design of binary solids.
Anca B. Calmuschi
Chiral Cyclopalladated Primary Amines as Building Blocks for Predictable Molecular Assemblies
ISBN : 978-3-86130-403-6