Can I read Helical Supramolecular Aggregates Based on Ureidopyrimidinone Quadruple Hydrogen Bonding on EtoBox?

Helical Supramolecular Aggregates Based on Ureidopyrimidinone Quadruple Hydrogen Bonding by J. H. K. Ky Hirschberg; Rolf A. Koevoets; Rint P. Sijbesma; E. W. Meijer is a Chemistry article available to read on EtoBox.

What is Helical Supramolecular Aggregates Based on Ureidopyrimidinone Quadruple Hydrogen Bonding about?

A series of mono- and bifunctional compounds 2-7, based on the ureido pyrimidinone quadruple hydrogen bonding unit, was prepared to study the mode of aggregation of these compounds in the bulk and in solution. Compounds 2-7 exhibit thermotropic liquid crystalline properties, as evidenced by differential scanning calorimetry and optical polarization microscopy. The presence of an ordered hexagonal discotic (D(ho)) phase of 2 a was confirmed by X-ray diffraction on an aligned sample. In chloroform, the bifunctional compounds form cyclic dimers at millimolar concentrations, and these dimers exist in equilibrium with linear species above a critical concentration, which may be from 6 mM to greater than 260 mM, depending on the structure of the spacer. Circular dichroism measurements in chloroform did not show a Cotton effect. Dodecane solutions of compounds 3, 4 b, and 7 b display a Cotton effect at the absorption band of the phenyl-pyrimidinone unit. Amplification of chirality was observed in mixtures of 7 a and 7 b, but not in mixtures of 4 a and 4 b, indicating that 7 a and 7 b form mixed polymeric aggregates with a helical architecture in dodecane solution, whereas 4 a and 4 b do no

Who reads Helical Supramolecular Aggregates Based on Ureidopyrimidinone Quadruple Hydrogen Bonding?

Author

J. H. K. Ky Hirschberg; Rolf A. Koevoets; Rint P. Sijbesma; E. W. Meijer

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Ltd.; Wiley (ISSN 0947-6539)

Published

2003

Language

EN

Field

Chemistry (Physical Sciences)