Imprinting chiral information into rigidified dendrimers

Chiral, polymerizable P2Pt(S-BINOL) metallodendrimers constructed of flexible benzyl ether repeat units were cross-linked/imprinted into highly porous and rigid organic polymers (methaerylate-based). Two meta-Cl substituents on the P-Ar portion of the metallomonomer reduced BINOL loss during polymer formation to levels that enabled site accessibility to be measured by the quantitation of S-BINOL cleavage (HCl) and BINOL/Br2BINOL exchange reactions. In general, the total site accessibility decreased as the generation number or steric bulk of the dendritic arms increased, which was offset by an increased effectiveness of the chiral imprint as the size of the dendritic arms increased. Thus polymerizable dendritic metallomonomers can be copolymerized into highly cross-linked organic polymers, and a memory for the absolute stereochemistry of the imprint ligand retained and used to affect the stereochemistry of reactions at the metal in the core.