Polymers Connected with Quadruple Hydrogen Bonds

Polymers Connected with Quadruple Hydrogen Bonds 

27 Quadruple hydrogen bonds with binding constants of 6 x 10 M left) and 2 X 10 right) 

Within the quadrupolar hydrogen-bonding systems, three aspects are significant (1) the action of the association in diluted liquid solution, (2) the ordering in the solid state, most of all the mechanical properties of the associates, and (3) methods to investigate and prove the ordering process. The latter is strongly related to electric- and optical properties. 

Another effect studied intensely in solution concerns the reversible switching of association-equilibria by photochemical effects. Blocked o-nitrobenzyl 

A combination of two different supramolecular forces, namely metal-metal bonds and the ureidopyrimidones were investigated by Schubert et al. [136,137] (Fig. 35). A poly(g-caprolactame) was prepared—with a ter-pyridine moiety at one end and an ureidopyrimidone unit at the other end—via tin-octanoate catalyzed polymerization. Together with iron(ll) ions, double supramolecular polymers formed from chloroform solution. Again, solid-like behavior was observed, similar to results for the purely hydrogen-bonded polymers. 

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Polymers Connected with Quadruple Hydrogen Bonds... 

The next case in Table 2 adds additional insight on helix formation by discotic components. Polymer 10 based on the bifunctional ureidotriazine unimer (F = 2,5 = 8) is stabilized by quadruple H-bonds. At variance with the somewhat similar polymer 1 (Table 1), a very short spacer connects the two hydrogen-bonding terminals of each unimer. A coiling chain might be expected with H-bonded extended core discotics interconnected by the spacers. However, the arene-arene interaction should favor a columnar stacking of the disks externally connected by the spacers. In fact, SANS data for decane solutions (0.2% to 1.0%) of the achiral unimer (R = C12H25) revealed the occurrence of... 

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