Magnetic Polymer Chains of Iron and Zwitterionic Quinoidal Ligands on the Ag(111) Surface

On-surface polymerization of iron atoms and zwitterion quinone (ZQ) molecules on Ag(111) is studied experimentally under ultra-high vacuum and theoretically in the framework of density functional theory. The resulting one-dimensional (1D) polymer chain is a promising model system to study both magnetic and conductive properties in one dimension. Previously we have shown that such polymer synthesis is possible over large scale by a controlled co-deposition of the two elements (i. e. metal and molecule) on a Ag(111) substrate (Nano Res. 2017, 10, 933). In that case, polymer chains are bound together to form a two-dimensional (2D) arrangement of spin chains influencing the magnetic properties of individual chains. Here we show that individual chains can be obtained using a sequential deposition of first metals and then ligands by scanning tunnelling microscopy on the Ag(111) surface. Ab-initio calculations are used to compare the atomic, electronic and magnetic structures of isolated Fe-ZQ polymer chains (1D...