Sublimation of alkali halides (NaCl and LiCl) onto a pre-assembled hydrogen-bonded layer of TCNQ on Au(111) resulted in the formation of 2D ionic layers via a direct charge-transfer reaction without involvement of the substrate. The presented approach allows for the fabrication of different ionic layers, decoupled from the substrate and offering new, potentially interesting properties.

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Repulsive interactions: a staging of supramolecular aggregation from (0D) clusters to (1D) chains and (2D) assemblies as a function of molecular coverage of dipolar porphyrins adsorbed on the Ag(111) surface is described. It displays a complex interplay of both attractive and repulsive molecule-molecule interactions, the emergence of chirality, and the registry of the substrate.

The role of polar 4‐[p‐(dimethylamino)phenylethynyl]phenyl substituents, with a calculated dipole moment of 3.35 Debye, in the self‐assembly of trans‐A2B2‐ and A2BC‐substituted porphyrins was explored in the solid state by X‐ray crystallography, and on an Au(111) surface by scanning tunneling microscopy (STM). Our results demonstrate that the dipolar character of these substituents blocks the 2D self‐assembly of porphyrins into larger ordered domains on Au(111) at low coverage, whereas antiparallel dipole–dipole interactions govern the molecular ordering in the crystal. The STM analysis revealed an adaptation of the conformation of the prochiral building blocks and a site‐selectivity of the adsorption. We present a general protocol for testing the suitability of higher‐molecular‐weight compounds, such as porphyrins, to be deposited on surface by sublimation in ultra‐high vacuum (UHV). This protocol combines classical methods of chemical analysis with typical surface science techniques.

In the crystal structure of the title compound, C10H10N3+·Cl−·[P(O)(OH)2H], the chloride ion and phospho­rous acid form a one‐dimensional hydrogen‐bonded chain, while the 2‐(2‐pyridylamino)pyridinium cations form a second chain through π–π stacking. The two parallel chains are connected via a PO⋯H—N hydrogen bond and a weak pyridinium‐to‐chloride inter­action.