Nature of supramolecular complexes controlled by the structure of the guest molecules: Formation of octa acid based capsuleplex and cavitandplex

Nithyanandhan Jayaraj, Yaopeng Zhao, Anand Parthasarathy, Mintu Porel, Robert S.H. Liu, V. Ramamurthy

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Factors that govern inclusion of organic molecules within octa acid (OA), a synthetic deep cavity cavitand, have been delineated by examining the complexation behavior of a number of organic molecules with varying dimensions and functionalities with OA. The formation of two types of complexes has been noted: the one which we call cavitandplex is a partially open complex in which a part of the guest molecule remains exposed to water, and the other termed capsuleplex is formed through assembly of two OA molecules. In capsuleplex, the guest is protected from water. Generally, guest molecules that possess ionic head groups form cavitandplex, and all others form capsuleplex. Capsuleplex may contain one or two guest molecules within the capsule. Small organic molecules (<10 Å in length) may form both 2:1 and 2:2 capsuleplex, while longer ones (>12 Å) preferentially form 2:1 capsuleplex. Extensive 1H NMR experiments have been carried out to characterize host-guest complexes. In the absence of the guest,OAtends to aggregate in water. The extent of aggregation depends on the concentration of OA and the presence of salts in solution. We expect the information obtained from this study to be of great value in predicting the nature of complexes with a given guest and facilitating appropriate guest chosen by researchers.

Original languageEnglish (US)
Pages (from-to)10575-10586
Number of pages12
JournalLangmuir
Volume25
Issue number18
DOIs
StatePublished - Sep 15 2009

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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