Supramolecular libraries

In this context the supramolecular crystalline [15-22] or hybrid materials [23-35] can be prepared and constitutionally self-sorted by using an irreversible kinetic process like crystallization or sol-gel polymerization. The self-selection is based on constitutional internal interactions of library components, resulting in the dynamic amplification of self-optimized architectures, during the phase change process. With all this in mind, the second part will be devoted to sol-gel resolution of dynamic molecular supramolecular libraries, emphasizing recent developments, especially as pursued in our laboratory. 

Self-Assembly Definition and Kinetic and Thermodynamic Considerations, p. 1248 Supramolecular Libraries, p. 1427 The Template Ejfect, p. 1493... 

Scheme 36.18 Use of a supramolecular ligand library in enantioselective hydrogenation.

The use of supramolecular ligand libraries in homogeneous catalysis was reviewed by Breit [54]. 

The supramolecular transformation from sphere to cylinder is supported by X-ray data indicating that the spherical polymers adopt a cubic phase, whereas the cylindrical polymers adopt a hexagonal phase [23b]. Further studies involving a library of dendritic macromonomers led to the conclusion that the effect of DP on polymer shape is a general phenomenon [24], More recently, scanning... 

Hue, I. Lehn, J. M. Virtual combinatorial libraries Dynamic generation of molecular and supramolecular diversity by self-assembly. Proc. Natl. Acad. Sci. U.S.A. 1997,94,2106-2110. 

Lohmeijer BGG, Wouters D, Yin Z, Schubert US (2004) Block copolymer libraries using supramolecular strategies. Polym Mater Sci Eng 90 723-724... 

The morphology of this supramolecular diblock copolymer library has been investigated by means of atomic force microscopy (AFM) measurements. As illustrated in Fig. 21, at first glance different morphologies were obtained for different compositions. However, interpreting the phase behavior of supramolecular block copolymers is not straightforward. There are several important parameters that play a role in the phase behavior. For instance, the amorphous phase of PEG, the crystalline phase of PEG, the metal complex, and the amorphous PSt contribute to... 

Dynamic combinatorial libraries (DCLs) are continuously interconverting libraries that evenmally evolve to an equilibrium distribution [61-65]. This approach has been used successfully in the discovery of stable supramolecular assemblies from mixtures. Due to the nearly endless possible peptide sequences that can potentially be synthesised, the DCL approach is attractive for the identification of supramolecular peptide interactions. Indeed, disulfide exchange between cysteine residues has been explored for this purpose [66, 67] as has peptide-metal binding [68]. We have recently demonstrated protease-catalysed amide exchange in this context, which allows for the evolution of the self-assembled peptide structures, and will therefore allow exploration of peptide sequence space for biomaterials design. 

Thus, dynamic peptide libraries offer the potential to identify the most stable self-assembled supramolecular nanostructure from a mixture of several components. This opens up the possibility of exploiting the versatility of peptides for the discovery of new nanostructures. 

The advancements in supramolecular catalysis are not limited to transitions-metal catalyzed reactions. Clarke and coworkers recently reported the preparation of a library of organocatalysts and their application in the asymmetric Michael addition of ketones to nitroalkenes [37]. They proposed use of a supramolecular catalyst formed... 

Figure 1.15 Supramolecular catalysts for organocatalysis (a) Route to catalyst libraries (b) asymmetric nitro-Michael reaction.

Breit, B. (2005) Supramolecular approaches to generate libraries of chelating bidentate ligands for homogeneous catalysis. Angeiv. Chem., Int. Ed.. 44, 6816-6825. 

Supramolecular Construction of Chelating Bidentate Ligand Libraries through Hydrogen Bonding Concept and Applications in Homogeneous Metal Complex Catalysis... 

I 2 Supramolecular Construction of Chelating Bidentate Ligand Libraries... 

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