Dynamic combinatorial chemistry: Substrate H-bonding directed assembly of receptors based on bipyridine-metal complexes

The functionalized ligands 1 and 2 bearing hydrogen-bonding recognition groups have been synthesized. Their assembly by metal ions such as Cu(I) and Pd(II) having different coordination geometries generates different receptor architectures for the binding of suitable substrates. Addition of the complementary bis(imide) Janus molecules (4-7) to [1a, 2a, CuTf] or to [1b, 2b, Pd(BF₄)₂] mixtures leads to a moderate selective increase of the fraction of the [(1a)₂Cu]⁺ or [(1b)₂Pd]²⁺ complex depending on the Janus substrate used. Largest enhancements are observed for those Janus substrates that may be expected to display highest geometrical complementarity with the two complexes. These results represent a process directed by target binding based on dynamic combinatorial chemistry. © 1999 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany