Chiral 3,3′-disubstituted BINOL derivatives: Syntheses, characterizations and X-ray structure analyses

Two chiral 3,3′-disubstituted BINOL derivatives 3a and 3b have been synthesized and their crystal structures have been reported. Their direct evidence of the solid-state conformations and their structural details of the unique 2D supramolecular architectures have been obtained. The intramolecular hydrogen bonds of both compounds lock two substituents at 3,3′-positions (like two arms) towards exterior around naphthyl backbones in an extended conformations. In the (R)-3a crystals, the uniform hand-to-hand intermolecular hydrogen bonds of OHN link the adjacent molecules into the infinite chainlike structure, and the π–π stacking interactions and the inter-aggregate Cl/Cl close connections result in forming the higher-order 2D supramolecular crossbedded self-adhesive architecture. For (R)-3b, the structural characteristics of the self-assembly is to form supramolecular crossbedded self-adhesive structure through the cooperative hydrogen bonding.