Transfer of chirality from ligands to metal centers: recent examples

Abstract

Recent examples of "chiral at metal" complexes and assemblies that are produced by chirality transfer of information from enantiopure ligands to metal ions are reported. They highlight the new progress that has been made in this area in the last two years and the new tendencies that such a topic is following. Besides the fundamental aspects related to the stereoselective synthesis of chiral complexes, the progress in diverse classes of chiral complexes for applications in materials science (chiral switches and molecular machines, biological mimics, CPL probes, etc.) is reported.

Supramolecular Chirality in Dynamic Coordination Chemistry

“…Metalloporphyrins and coordinatively unsaturated lanthanide complexes are typical examples for chirality induction exhibiting chirality sensing of external substrates via dynamic coordination [29][30][31]. Furthermore, the metal complexes can function as chiral building units for a variety of molecular geometries including linear, triangular, tetrahedral, octahedral, and higher polyhedral structures [32][33][34][35], some of which are easily converted to each other in response to environmental conditions. Their stereoisomers often have similar free energy, which results in labile metal complexes being generated as a racemate and/or coexisting in solution ( Figure 1).…”

Dynamic Helicity Control of Oligo(salamo)-Based Metal Helicates

“…To date, various types of chemical and other stimuli have been used to achieve dynamic helicity inversion of the helical structures such as polymers, metal helicates, etc. [18][19][20][21][22][23][24]. …”

“…Since the P and M forms are in dynamic equilibrium, we can change the P/M equilibrium ratio by the addition/removal or modification of the chiral auxiliary. This would lead to responsive helicity changes and inversions as described the Section 1.3, which are recognized as one of the hot topics in functional molecular chemistry [18][19][20][21][22][23][24]. ( Figure 3a), we have to convert the enantiomer pair into a diastereomer pair by the introduction of a chiral auxiliary.…”

The Chain of Chirality Transfer as Determinant of Brain Functional Laterality. Breaking the Chirality Silence: Search for New Generation of Biomarkers; Relevance to Neurodegenerative Diseases, Cognitive Psychology, and Nutrition Science

“…The diversity of stereospecific (chiral) phenomena was observed in molecular structures including chirality recognition/sensing [95,96], chirality transfer [97], chirality/helicity induction [98][99][100][101], chirality amplification [102][103][104], chirality breaking [61,105], chirality conflict [106,107], helicity inversion [108][109][110], and chiral phase transitions XVII [111][112][113][114]116]. Progress in the studies of molecular chirality transformation is helpful in resolving three questions.…”

“…In the quantum spin systems, the symmetry-related phase transitions [78,154,155] and the transfer of the stereospecific (symmetry) characters XXIV [97,156] are well-known phenomena. The recent advance in the experimental and theoretical areas of many disciplines related to stereochemistry revealed the chirality-induction effects in the various inorganic materials with mono-chiral and hybrid-chirality structures including plasmonic, semiconducting, metal oxide and silica-based compounds [170].…”