Helical versus all-trans conformations of oligo(ethylene glycol)-terminated alkanethiol self-assembled monolayers

Langmuir. 2014 Sep 2;30(34):10263-9. doi: 10.1021/la500978s. Epub 2014 Aug 18.

Abstract

The complex mixture of conformational states exhibited by oligo(ethylene glycol)-terminated alkanethiols on Ag and Au surfaces is explored by polarization-dependent X-ray absorption spectroscopy. Three self-assembled monolayers (SAMs) with known helical or all-trans conformations are used as references to characterize a SAM with unknown conformations. This case study is used as a prototype for developing a systematic framework to extract the conformations of SAMs from the polarization dependence of several orbitals. In the case at hand, these are associated with the C-H/Rydberg bonds of the alkane, the C-H/Rydberg bonds of ethylene glycol, and the C-C bonds of the backbone. The C-H/Rydberg orbitals of the alkane and ethylene glycol are distinguished via the chemical shift of the corresponding C 1s core levels.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alkanes / chemistry*
  • Ethylene Glycol / chemistry*
  • Molecular Conformation
  • Sulfhydryl Compounds / chemistry*
  • X-Ray Absorption Spectroscopy

Substances

  • Alkanes
  • Sulfhydryl Compounds
  • Ethylene Glycol