Self‐Assembly of a Mononuclear [FeIII(L)(EtOH)2] Complex Bearing an n‐Dodecyl Chain on Solid Highly Oriented Pyrolytic Graphite Surfaces |
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Authors: | Dr Ayuk M Ako Dr Mohammad Sahabul Alam Mostafizur Rahman Dr Jonathan P Hill Dr Noelia M Sanchez‐Ballester Dr Katsuhiko Ariga Dr Gernot Buth Dr Christopher E Anson Prof?Dr Annie K Powell |
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Institution: | 1. Institut für Anorganische Chemie, Karlsruhe Institute of Technology, Engesserstrasse 15, 76128 Karlsruhe (Germany), Fax: (+49)?721‐608‐48142;2. Department of Physics, University of Dhaka, Curzon Hall, Dhaka‐1000 (Bangladesh);3. WPI‐International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1‐1, Tsukuba, Ibaraki 305‐0044 (Japan), Fax: (+81)?29‐860‐4832;4. Institute of Synchrotron Radiation (ISS), Karlsruhe Institute of Technology, Hermann‐von‐Helmholtz‐Platz 1, Eggenstein‐Leopoldshafen (Germany);5. Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann‐von‐Helmholtz‐Platz 1, Eggenstein‐Leopoldshafen (Germany) |
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Abstract: | The synthesis and structures of the N‐(2‐hydroxy‐3‐methyl‐5‐dodecylphenyl)methyl]‐N‐(carboxymethyl)glycine disodium salt (H L ) ligand and its neutral mononuclear complex FeIII( L )(EtOH)2] ( 1 ) are reported. Structural and electronic properties of 1 were investigated by using scanning tunneling microscopy (STM) and current imaging tunneling spectroscopy (CITS) techniques. These studies reveal that molecules of 1 form well‐ordered self‐assemblies when deposited on a highly oriented pyrolytic graphite (HOPG) surface. At low concentrations, single or double chains (i.e., nanowires) of the complex were observed, whereas at high concentration the complex forms crystals and densely packed one‐dimensional structures. In STM topographies, the dimensions of assemblies of 1 found on the surface are consistent with dimensions obtained from X‐ray crystallography, which indicates the strong similarities between the crystal form and surface assembled states. Double chains are attributed to hydrogen‐bonding interactions and the molecules align preferentially along graphite defects. In the CITS image of complex 1 a strong tunneling current contrast at the positions of the metal ions was observed. These data were interpreted and reveal that the bonds coordinating the metal ions are weaker than those of the surrounding ligands; therefore the energy levels next to the Fermi energy of the molecule should be dominated by metal‐ion orbitals. |
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Keywords: | electron microscopy graphite iron nanostructures self‐assembly |
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