Helical Chirality Transmission through a p-Phenylene Fragment in a Hexa-λ⁵-phosphazene

Abstract

The helical chirality of a conformationally stable macrobicyclic tri-lambda5-phosphazene is propagated through to its C3 symmetry axis and causes a measurable stereoinduction in the formation process of a second macrobicyclic tri-lambda5-phosphazene unit connected to the former one by a p-phenylene linker.

Does an Axial Propeller Shape on a Dirhodium(III,III) Core Affect Equatorial Ligand Chirality?

“…However, only bisphenyl-dirhodium(III,III) tetrakis(1-aza-2-cyclooctanoate) having the propeller conformation is formed with the higher homologue of caprolactam, 1-aza-2-cyclooctanone (ACOH), as the bridging ligand . Molecular propellers have been recognized in organic chemistry as well-defined architectures that can exhibit restricted conformational equilibria, and significant advances in stereochemical applications have resulted from these studies, but there have been no previous reports of a propeller structure having a dimetallic core. However, although previously reported carbon-based molecular propellers often have a low energy barrier for interconversion between the two forms, the propeller conformation in bisphenyldirhodium(III,III) carboxamidates does not exhibit an energetically favorable interconversion between biplanar and propeller conformers even at high temperatures as a solid or in solution .…”