Jos Marie Johannes Paulusse

Self‐Assembly of Ureido‐Pyrimidinone Dimers into One‐Dimensional Stacks by Lateral Hydrogen Bonding

Ureido-pyrimidinone (UPy) dimers substituted with an additional urea functionality self-assemble into one-dimensional stacks in various solvents through lateral non-covalent interactions. (1)H NMR and DOSY studies in CDCl(3) suggest the formation of short stacks (<10), whereas temperature-dependent circular dichroism (CD) studies on chiral UPy dimers in heptane show the formation of much larger helical stacks. Analysis of the concentration-dependent evolution of chemical shift in CDCl(3) and the temperature-dependent CD effect in heptane suggest that this self-assembly process follows an isodesmic pathway in both solvents. The length of the aggregates is influenced by substituents attached to the urea functionality. In sharp contrast, UPy dimers carrying an additional urethane group do not self-assemble into ordered stacks, as is evident from the absence of a CD effect in heptane and the concentration-independent chemical shift of the alkylidene proton of the pyrimidinone ring in CDCl(3).

A high molecular weight reversible coordination polymer of PdCl2 and 1,12-bis(diphenylphosphino)dodecaneElectronic supplementary information (ESI) available: experimental details, SEC results and NMR spectra. See http://www.rsc.org/suppdata/cc/b3/b301874a/

1,12-Bis(diphenylphosphino)dodecane and PdCl2 are shown to form linear supramolecular polymers in equilibrium with cyclic structures; high molecular weight material was obtained by melt polymerisation.