Electrostatic-interaction-induced molecular deposition of a hybrid bilayer on Au(111): a scanning tunneling microscopy study

In Situ Scanning Tunneling Microscopy of Cobalt-Phthalocyanine-Catalyzed CO2 Reduction Reaction

We report a molecular investigation of a cobalt phthalocyanine (CoPc)-catalyzed CO₂ reduction reaction by electrochemical scanning tunneling microscopy (ECSTM). An ordered adlayer of CoPc was prepared on Au(111). Approximately 14 % of the adsorbed species appeared with high contrast in a CO₂ -purged electrolyte environment. The ECSTM experiments indicate the proportion of high-contrast species correlated with the reduction of Co^II Pc (-0.2 V vs. saturated calomel electrode (SCE)). The high-contrast species is ascribed to the CoPc-CO₂ complex, which is further confirmed by theoretical simulation. The sharp contrast change from CoPc-CO₂ to CoPc is revealed by in situ ECSTM characterization of the reaction. Potential step experiments provide dynamic information for the initial stage of the reaction, which include the reduction of CoPc and the binding of CO₂ , and the latter is the rate-limiting step. The rate constant of the formation and dissociation of CoPc-CO₂ is estimated on the basis of the in situ ECSTM experiment.

Fabrication of bilayer tetrathiafulvalene integrated surface covalent organic frameworks

A bilayer covalent organic framework (COF) of TTF-based building blocks was obtained by imine reaction between tetrathiafulvalene tetraaldehyde (4ATTF) and p-phenylenediamine (PPDA). Direct evidence for the eclipsed stacking of bilayer structure via π-π interaction between TTF units is provided by high resolution scanning tunneling microscopy.

Ionic interaction-induced assemblies of bimolecular “chessboard” structures

Here we applied ionic interactions as the driving force to fabricate well-ordered bicomponent assemblies by using two porphyrin ions equipped with oppositely-charged groups.