Dynamic Combinatorial Libraries Based on Hydrogen-Bonded Molecular Boxes

This article describes two different types of dynamic combinatorial libraries of host and guest molecules. The first part of this article describes the encapsulation of alizarin trimer 2 a3 by dynamic mixtures of up to twenty different self-assembled molecular receptors together with the amplification and selection of the best binder. Receptors (1 a-d)3(DEB)6 are formed by the self-assembly of six diethyl barbiturate (DEB) and calix[4]arene dimelamine derivatives 1 a-d by using hydrogen bonds. The largest amplification factor (2.8) for a host assembly (1 a3 (DEB)6) was observed after the addition of 2 a to four-component library 1 an1 b(3-n)(DEB)6 (n=0-3). Addition of 2 a to twenty-component library 1 an1 bm1 co1 d(3-(n+m+o))(DEB)6 (n, m, o=0-3; (n+m+o)3) also showed amplification of receptor 1 a3(DEB)6. The second part of this article describes the complexation of libraries of different alizarin-like guest molecules (2 a-d) and the self-assembled receptor 1 a3(DEB)6. This receptor is able to template the formation of the best-fitting guest trimer