Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

Abstract

A study of the two-dimensional crystallization of rhodizonic acid on the crystalline surfaces of gold and copper is presented. Rhodizonic acid, a cyclic oxocarbon related to the ferroelectric croconic acid and the antiferroelectric squaric acid, has not been synthesized in bulk crystalline form yet. Capitalizing on surface-assisted molecular selfassembly, a two-dimensional analogue to the well-known solution-based coordination chemistry, two-dimensional structures of rhodizonic acid were stabilized under ultrahigh vacuum on Au(111) and Cu(111) surfaces. Scanning tunneling microscopy, coupled with first-principles calculations, reveals that on the less reactive Au surface, extended twodimensional islands of rhodizonic acid are formed, in which the molecules interact via hydrogen bonding and dispersion forces. However, the rhodizonic acid deprotonates into rhodizonate on Cu substrates upon annealing, forming magic clusters and metal−organic coordination networks with substrate adatoms. The networks show a 2:1 distribution of rhodizonate coordinated with 3 and 6 Cu atoms, respectively. The stabilization of crystalline structures of rhodizonic acid, structures not reported before, and their transition into metal−organic networks demonstrate the potential of surface chemistry to synthesize new and potential useful organic nanomaterials.

Benzene derivatives adsorbed to the Ag(111) surface: Binding sites and electronic structure

“…19,20 This in turn impacts intermoleca) Electronic mail: ezurek@buffalo.edu ular interactions, such as hydrogen bonding, van der Waals (vdW) attraction, as well as dipolar and Coulombic interactions. [21][22][23][24][25][26][27][28][29][30][31][32] Further complexity arises because the patterns into which molecules arrange can be coverage dependent, 33 different architectures can simultaneously co-exist, 34 and deprotonation, 35,36 as well as the incorporation of metal atoms arising from the surface into the network [37][38][39] can be important. Moreover, it has recently been shown that the relative alignment of the substrate and adsorbate atoms can influence reaction pathways and products.…”

Zwitterionic Systems Obtained by Condensation of Heteroaryl‐Boronic Acids and Rhodizonic Acid

“…[28,29] Proton transfer and ferroelectric properties have been studied of single layers of rhodizonic acid assembled on noble metal surfaces. [30,31] In this paper, we report the results of our study of the condensation reactions of rhodizonic acid and boronic acid derivatives aimed to prepare new building blocks for crystal engineering studies. [32] This is also in keeping with our investigation of the supramolecular assembly and solid-state properties of 4pyridinylboronic and of 4-(pyridine-4-yl)phenylboronic acid.…”

Influence of Structural Fluctuations, Proton Transfer, and Electric Field on Polarization Switching of Supported Two-Dimensional Hydrogen-Bonded Oxocarbon Monolayers

“…24 2D sheets of the related rhodizonic acid (RA, H 2 C 6 O 6 ) were investigated in another study. 25 While RA is hygroscopic and thus typically found in the form of RA dihydrate, 26 2D crystalline layers of RA have been successfully synthesized on Au(111) under ultrahigh vacuum. 25 The molecular dipole of RA is in the molecular plane as well, as shown in Supporting Information Figure S1(b).…”

“…The mechanism of electric-field induced switching of molecular dipoles in epitaxial 2D layers of CA 24 and RA, 25 and the role of the supporting substrates, are poorly understood at present. Thus, in this study, we investigate the field-induced polarization switching on two model systems: (1) a CA monolayer on Ag(111) surface and (2) a RA monolayer on Au(111) surface (see Figure 1).…”