Density functional theory analysis of carboxylate-bridged diiron units in two-dimensional metal-organic grids

Supramolecular engineering of metal-organic architectures on well-defined substrates is currently emerging as a promising route toward novel nanoscale systems and functional surfaces.1 Investiga-tions in this field, relying on scanning tunneling microscopy (STM) observations under ultrahigh vacuum conditions, revealed that on atomically clean metal surfaces an intriguing variety of low-dimensional metallosupramolecular arrangements can be synthe-sized by controlled deposition of polytopic linker molecules and transition metal centers. In particular, the assembly of nanoporous Fe-carboxylate metal-organic coordination networks (MOCNs) was achieved.2 Such 2-D MOCNs comprise regular arrays of coordinatively unsaturated metal centers and distinct nanocavities which proved to be suitable as versatile and robust templates for the organization of appropriate guest species. However, while the STM investigations allow for molecular-level elucidation o