Binding Geometry of Hydrogen-Bonded Chain Motif in Self-Assembled Gratings and Layers on Ag(111)

Abstract

Upon adsorption on the (111) facet of Ag, 4-[trans-2-(pyrid-4-yl-vinyl)] benzoic acid (PVBA) self-assembles into a highly ordered, chiral twin chain structure at submonolayer coverages with domains that can extend for micrometers in one dimension. Using polarization-dependent measurements of C and N K-shell excitations in near-edge X-ray absorption fine structure (NEXAFS) spectra, we determine the binding geometry of single PVBA molecules within this unique ensemble for both low and high coverage regimes. At submonolayer coverage, the molecule is twisted to facilitate the formation of hydrogen bonds. The gas-phase planarity is gradually recovered as the coverage is increased, with complete planarity coinciding with loss of order in the overlayer. Thermal treatment of the PVBA film results in deprotonation of the carboxyl tail of the molecule, but despite the suppression of the stabilizing hydrogen-bonds, the overlayer remains ordered.

Tailored Formation of N-Doped Nanoarchitectures by Diffusion-Controlled on-Surface (Cyclo)Dehydrogenation of Heteroaromatics

“…P3-C at 285.0 eV represents the carbon atoms in the pyridine ring. 6,9 Finally, the binding energy distance between P1-C and P4-C, around 1 eV, is constant throughout the whole annealing process (not shown here): therefore we tentatively assigned this component to a shake-up process.…”

“…All XPS spectra have been fitted by a convolution of a Lorentzian and a Gaussian functions with typical widths of 180 meV and 900 meV, respectively. The main peak P1-C at 284.3 can be assigned to the sp2 C atoms in the aromatic rings [6][7][8] , while P2-C (283.7) to C atoms bonded to H atoms. The binding energy difference between P1 and P2 (0.6 eV) is consistent with this assignation [6][7][8] .…”

“…The peak A at 284.4 eV corresponds to transitions of the C1s electrons to the Lowest Occupied Molecular Orbital (LUMO) of the aromatic rings peak 6 . The presence of the nearby LUMO+1 state may cause the asymmetry of the peak 10 .…”

Reversibility and intermediate steps as key tools for the growth of extended ordered polymers via on-surface synthesis

“…Ordered SAMs have been obtained by depositing a variety of molecules on several surfaces (including metals, semiconductors and insulators) and identifying the main parameters leading to the final molecular superstructure. A plethora of conformational moieties has been identified and studied in different conditions (solid-vacuum, solid-air and solid-liquid interfaces), unveiling the details of the assembly [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. The subtle balance between intermolecular and molecule-surface interactions governs molecular self-assembly on surfaces which can be controlled by changing the molecules (composition and geometry), the substrate, the chirality, and external factors, such as temperature and pH.…”

Linear dichroism in the NEXAFS spectra of n-alkane crystalline polymorphs

“…NEXAFS spectroscopy is often used to study the chemical composition [1][2][3][4][5][6][7] and bonding [1,[8][9][10] in organic molecules. In NEXAFS spectroscopy, spectral features are often described as one electron transitions from core electron (e.g.…”