Distinct differences in self-assembly of aromatic linear dicarboxylic acids

Langmuir. 2009 Jan 20;25(2):968-72. doi: 10.1021/la803055p.

Abstract

Self-assembly into two-dimensionally ordered supramolecular structures of three aromatic dicarboxylic acids-2,6-naphthalenedicarboxylic acid (NDA), 4,4'-biphenyldicarboxylic acid (BPDA), and 4,4'-stilbenedicarboxylic acid (SDA)-is studied at the liquid-solid interface by scanning tunneling microscopy. All compounds possess structural similarities, namely, two interconnected aromatic moieties and functionalization through two carboxylic groups in linear configuration. For all molecules, ordered monolayers were observed on a graphite substrate, and the resulting structures can be described as a dense packing of one-dimensionally hydrogen-bonded rows. However, concerning the stability of the adsorbate layers, the average domain size, and the degree of order, distinct differences were noticed. Supported by density functional theory (DFT) calculations, these differences are analyzed and explained as a consequence of molecular structure, adsorption geometry, and adsorption energy.

MeSH terms

  • Adsorption
  • Biphenyl Compounds / chemistry*
  • Dicarboxylic Acids / chemistry*
  • Hydrogen Bonding
  • Microscopy, Scanning Tunneling
  • Models, Chemical
  • Molecular Structure
  • Naphthalenes / chemistry*
  • Particle Size
  • Stilbenes / chemistry*
  • Surface Properties

Substances

  • 4,4'-biphenyldicarboxylic acid
  • 4,4'-stilbenedicarboxylic acid
  • Biphenyl Compounds
  • Dicarboxylic Acids
  • Naphthalenes
  • Stilbenes
  • 2,6-naphthalenedicarboxylic acid