Structure, morphology and interface properties of ultrathin SnTTBPP(OH)2-films adsorbed on Ag(100)

Abstract

The molecular interaction of dihydroxo[5,10,15,20-tetrakis(4-tert-butyl-phenyl)porphyrinato]-tin(IV) (SnTTBPP(OH)(2)), the structural order and growth of ultrathin films on Ag(100) have been studied by means of low-energy electron diffraction (LEED) and synchrotron based photoelectron spectroscopy, i.e., X-ray photoemission (XPS) and near-edge X-ray absorption fine structure (NEXAFS/XANES) spectroscopy. For the first time, monolayer adsorption of a metalloporphyrin with octahedral coordination of the metal center by two additional axial hydroxo ligands is investigated in a multi-technique study. The delicate balance of molecule-substrate interactions and intermolecular interactions leads to the formation of a densely-packed organic monolayer which is commensurate with the Ag(100) substrate. From NEXAFS linear dichroism an almost coplanar orientation of the porphyrin system is derived. XPS and NEXAFS clearly indicate that the axial hydroxo ligands are cleaved in monolayer films, i.e., upon adsorption to the Ag substrate. With increasing film thickness orientational order gets lost and leads to polycrystalline growth for thicker films as confirmed by scanning X-ray transmission microscopy (STXM).

Surface chemistry of porphyrins and phthalocyanines

“…Details about the commensurate monolayer structure with a square unit cell are listed in Table 3a. In the multilayer, the orientational order was lost with increasing thickness [407].…”

“…SnTBPP monolayers on Ag(1 0 0) were produced by annealing of (OH) 2 SnTBPP multilayers to 580 K [407]. The OH groups were apparently lost during the annealing and as a result, the porphyrin plane was nearly parallel to the surface, according to NEXAFS.…”

Chirogenesis in Zinc Porphyrins: Theoretical Evaluation of Electronic Transitions, Controlling Structural Factors and Axial Ligation

“…In this work the geometry optimization was performed using RI[ 158 , 159 , 160 ]‐BP86[ 161 , 162 ]‐D3 [163] /def2‐SV(P) [164] implemented in Turbomole 7.0 [165] – the method which showed a good agreement with the experimental data reported in previous works. [ 98 , 99 , 166 , 167 ] The geometries of the complexes are given in SI.…”

Adsorption Structure of Cobalt Tetraphenylporphyrin on Ag(100)

“…Extensive research has been carried out in this area with photoelectron spectroscopy, scanning tunneling microscopy (STM), and low-energy electron diffraction (LEED). These studies have focused on the bonding between the surface and the molecule, especially the metal center, − the influence and orientation of substituents such as phenyl groups, ,− and the molecular long-range order. − ,,− However, the vast majority of work has focused on close-packed (111) metal surfaces. In this work, we now investigate the adsorption of cobalt 5,10,15,20-tetraphenyl­porphyrin (CoTPP) (Figure ) on the more open surface Ag(100) surface, in order to search for a possible influence of the crystallographic orientation of the substrate.…”