2D NETWORKS BY DEPOSITION OF PD-CYCLOMETALLATES ON AG(110)

Among possible organometallic compounds, complexes of the Group 10 elements are attractive due to their widespread use in numerous applications such as catalytic synthetic processes, biological chemistry, and material science. Many palladium complexes have been extensively studied as catalysts in several cross-coupling reactions and while great advancements have been made on the synthesis of transition metal complexes with specifically designed properties, our understanding about their interactions with metal surfaces is still quite limited. Their coupling to a surface is of interest, since their self-assembly on metal surfaces could lead to a major impact in catalysis and sensoristics. My Ph.D. thesis enters this field, in the framework of the projects “MC-nano” (by Fondazione Compagnia di San Paolo) and “MADAM - Metal Activated low dimensional carbon-based nanostructures”, (PRIN2017, by MUR). I did my research work in the joint IMEM-DIFI laboratory, at the Department of Physics of University of Genoa, under the supervision of prof. G. Bracco and Dr. L. Savio. I worked in collaboration with partners from Università di Milano Bicocca and with the staff of the ALOISA beamline of the ELETTRA Synchrotron Light Source in Trieste since most of the XPS measurements were performed during a beamtime there. I investigated the self-assembly and thermal evolution of two palladium cyclomatellated compounds: C22H14Br2Cl2N2Pd2 (CyPd) and C22H16Cl2N2Pd2 (CyPd_2). Such class of molecules were deposited on Ag(110) for the first time. The systems were studied for different coverages and annealing temperatures from RT to 500 °C by low-temperature scanning tunneling microscopy. The results were interpreted in combination with complementary photoemission spectroscopy measurements and theoretical calculations performed by the partner groups. My data reports on the long range and well-ordered self-assemblies formed by Pd cyclomatellated compounds on Ag(110) by STM. It highlights the active role of the substrate which promotes dissociation of the molecules upon adsorption, and the role of molecular geometry on the morphology of the nanostructure. Annealing the CyPd or CyPd_2/ Ag(110) system to 100 °C or above leads to the formation of new structures and surface reconstruction.