Molecular mechanics hydrogen-bonding interactions

Mechanistic studies on this system have demonstrated that the reaction does not follow a simple stepwise condensation pathway as first assumed. Instead, the authors have proposed a divergent mechanism by which the production of 2 and 3 are linked by a common intermediate (see Scheme 3). In such a mechanism, hydrogen-bonding interactions between the donor molecular moieties and the templating halide (acceptor) play an important role. 

Because of the vastness of the subject matter, we shall focus our attention on hydrogen bonding interactions between ions and on the possibilities and limitations of their use in the design and construction of molecular materials of desired architectures and/or destined to predetermined functions. Obviously, the crystal engineer (or supramolecular chemist) needs to know the nature of the forces s/he is planning to master, since molecular and ionic crystals, even if constructed with similar building blocks, differ substantially in chemical and physical properties (solubility, melting points, conductivity, mechanical robustness, etc.). 

Because of their reversible chain extension and the subsequent formation of small crystalline domains, the functionalized polymers exhibit properties typical for thermoplastic elastomers. At low temperatures the hydrogen-bond interaction contributes to the properties comparable to covalent interactions, whereas at high temperatures these interactions disappear and the materials exhibit flow behavior typical for a low-molecular-weight polymer. DSC,72 73 light and X-ray scattering,7174 dynamical mechanical analy-... 

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