Magnetic properties of transmetalated porphyrin-based coordinative polymers

Porphyrins (Por) and other macrocycles present a wide variety of functional properties with prospective applications in fields such as sensing, catalysis, biomedicine and optoelectronics. In particular, surface-supported porphyrins and 2D assemblies of porphyrin derivatives offer the possibility of reducing metal clustering to the atom level for applications that are surface-dependent, such as heterogeneous catalysis or for gas-fixing purposes. The already proven evidence that the metal atoms in surface-supported Por can be replaced in situ by transmetalation provides a step-wise analysis of the evolution of the electronic and magnetic properties of these systems. However, the mechanism is rarely evidenced yet. Scanning Tunneling Microscopy and Spectroscopy (STM and STS) is a powerful tool to unveil these changes. However, it presents some limitations in order to identify the chemical composition of the metal center (oxidation state), and the magnetic character, even more puzzling when it is a transmetalated species. Here we propose the investigation of the fundamental properties of coordinating polymers based on surface synthesised phenalenyl-extended Zn-Por, and their consequent transmetalated species with cobalt (Co-Por) on Au(111)/mica. We intend to get insights into the chemical state, charge anisotropy, magnetic anisotropy, orientation of spin axis and quantum numbers. The chemical, electronic and magnetic properties of these polymers will be measured by X-ray absorption (XAS), linear dichroism (XLD) and magnetic circular dichroism (XMCD).