Seeking out Heterogeneous Hydrogen Bonding in a Self-Assembled 2D Cocrystal of Croconic Acid and Benzimidazole on Au(111)

Daniel P. Miller, Paulo S. Costa, Jacob D. Teeter, Alexander Sinitskii, Axel Enders, James G.M. Hooper

Research output: Contribution to journalArticlepeer-review

Abstract

A two-dimensional (2D) hydrogen-bonded cocrystal was synthesized from croconic acid (CA) and benzimidazole (BI) on a gold surface under ultrahigh vacuum conditions. The network domains have a 1:1 CA/BI stoichiometry, can be synthesized over a range of temperatures, and contain one-dimensional chains of molecules connected by heterogeneous hydrogen bonds. Density functional theory (DFT) computations suggest that a tautomeric salt-like structure, with deprotonated CA and protonated BI, is the most stable model, which creates heterogeneous N-H···O contacts instead of N···H-O ones. The homogeneity of the network's appearance in scanning tunneling microscopy (STM) and a habitual change in the STM features under certain tip conditions indicate that there is an equilibrium of tautomeric molecular states that may be influenced to some degree by STM stimuli. Overall, this study demonstrates how careful consideration of the precursor molecules can tune the architecture within a family of cocrystal networks and introduce desired bonding motifs that haven't been achieved by solution-based synthesis for these species, such as the heterogeneous hydrogen bonds herein.

Original languageEnglish (US)
Pages (from-to)2403-2410
Number of pages8
JournalJournal of Physical Chemistry C
Volume125
Issue number4
DOIs
StatePublished - Feb 4 2021

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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