Disposition of the axial ligand in the physical vapor deposition of organometallic complexes

Axial ligands play an important role in the stabilization, functionality, and synthesis of many planar organometallic complexes. Axial ligands are often weakly bound and can easily be activated in catalytic reactions. Thermal activation and following dissociation processes have to be considered whenever sublimation procedures are used for the preparation of well-defined molecular samples under vacuum conditions. When the disposition of the axial ligand is unresolved, this potentially hampers a correct interpretation of experimental data. Here, the authors systematically address the axial ligand (X) in the system of FeIII-TriPhenylCorroles (FeTPC)-X with X=NO, 1/2 O, Cl, and (Et2O)2 adsorbed on Cu(111) in a scanning tunneling microscopy study. The authors discuss undesired side effects due to released axial ligands which are coadsorbed on a surface. NO is identified like the most appropriate axial ligand for in situ preparation of uncoordinated FeTPC whereas the adsorption of axially coordinated FeTPC was ...