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