The synthesis of a Sauvage-type catenane featuring a quadruple hydrogen bonding ureidopyrimidinone (UPy) motif in each ring was reported. Intermolecular dimerization of the UPy motifs induces the hydrogen-bond-driven supramolecular polymerization of the catenane monomer, thereby creating a linear polymer consisting of both hydrogen bonding and mechanical bonds. As the rings in the UPy catenane are asymmetric, two stereoisomers can be formed upon catenation, that is, with the phenanthroline moieties oriented +90° or -90° with respect to each other. Based on the phenanthroline-Cu(I) and ring-closing metathesis (RCM) approach, we first devised a synthetic procedure for the synthesis of the UPy-based catenane. Here, phenanthroline was first functionalized with phenol moieties in a two-step approach with an overall yield of 46%. The resulting biphenol 3 was then alkylated in a statistical manner with a mixture of 4-bromobut-1-ene and t-Boc-protected bromide resulting in t-Boc-protected compound. The results show that protection of the UPy motifs is necessary for this reaction to reach completion. Analysis of the unprotected UPy catenane by 1H NMR revealed the formation of UPy-UPy dimers and significant broadening of the signals, both in presence and absence of Cu(I).
|Number of pages||6|
|Journal||Journal of Polymer Science, Part A: Polymer Chemistry|
|Publication status||Published - 15 Sep 2017|
- mechanical bond
- supramolecular polymer