Multiscale Approach to the Study of the Electronic Properties of Two Thiophene Curcuminoid Molecules

Alvaro Etcheverry-Berríos, I.J. Olavarria Contreras, Mickael L. Perrin, Raúl Díaz-Torres, Domingo Jullian, Ingrid Ponce, José H. Zagal, Jorge Pavez, Sergio O. Vásquez, Herre S.J. van der Zant, Diana Dulić, Núria Aliaga-Alcalde, Monica Soler

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)

Abstract

We studied the electronic and conductance properties of two thiophene–curcuminoid molecules, 2-thphCCM (1) and 3-thphCCM (2), in which the only structural difference is the position of the sulfur atoms in the thiophene terminal groups. We used electrochemical techniques as well as UV/Vis absorption studies to obtain the values of the HOMO–LUMO band gap energies, showing that molecule 1 has lower values than 2. Theoretical calculations show the same trend. Self-assembled monolayers (SAMs) of these molecules were studied by using electrochemistry, showing that the interaction with gold reduces drastically the HOMO–LUMO gap in both molecules to almost the same value. Single-molecule conductance measurements show that molecule 2 has two different conductance values, whereas molecule 1 exhibits only one. Based on theoretical calculations, we conclude that the lowest conductance value, similar in both molecules, corresponds to a van der Waals interaction between the thiophene ring and the electrodes. The one order of magnitude higher conductance value for molecule 2 corresponds to a coordinate (dative covalent) interaction between the sulfur atoms and the gold electrodes.

Original languageEnglish
Pages (from-to)12808-12818
Number of pages11
JournalChemistry: A European Journal
Volume22
Issue number36
DOIs
Publication statusPublished - 2016

Keywords

  • curcumin
  • density functional calculations
  • differential pulse voltammetry
  • HOMO–LUMO band gap energies
  • self-assembly

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