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Self‐Assembly of Ureido‐Pyrimidinone Dimers into One‐Dimensional Stacks by Lateral Hydrogen Bonding
Author(s) -
Nieuwenhuizen Marko M. L.,
de Greef Tom F. A.,
van der Bruggen Rob L. J.,
Paulusse Jos M. J.,
Appel Wilco P. J.,
Smulders Maarten M. J.,
Sijbesma Rint P.,
Meijer E. W.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902107
Subject(s) - heptane , chemistry , hydrogen bond , isodesmic reaction , circular dichroism , crystallography , covalent bond , ring (chemistry) , proton nmr , stereochemistry , molecule , organic chemistry
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 .