Chemistry Reference
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Figure 5.8 Three recognition motifs based on (a) hydrogen bonding interactions between
2,6-diaminopyridine and thymine, (b) metal coordination of sulfur-carbon-sulfur (SCS) Pd
pincer with pyridine, (c) pseudorotaxane formation between dibenzo[24]crown-8 (DB24C8)
and dibenzylammonium ions, and (d) fully functionalized terpolymer 5.
(South et al. 2006). Side chain functionalization of these terpolymers was achieved by
self-assembling 1) pyridines to the palladated pincer complexes, 2) dibenzylammo-
nium ions to the DB24C8 rings, and 3) thymine to the 2,6-diaminopyridine receptors.
By following the hydrogen bonding as well as the pseudorotaxane formation by
1
H-NMR spectroscopy and isothermal titration calorimetry, the Weck and Stoddart
groups were able to show that the association constants were unaffected by neighbor-
ing functionalities on the polymer backbone, demonstrating for the first time
orthogonality in the recognition expressed by three well-defined and discrete
recognition sites.
