K W Hipps - Scanning Tunneling Microscopy of Metal Phthalocyanines:  d6 and d8 Cases

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      Publication Details (including relevant citation   information):

      Lu, Xing, Hipps, K. W. The Journal of Physical Chemistry   B 1997 101 (27) 5391-5396

      Abstract: Scanning tunneling microscopy (STM)   images of iron(II) phthalocyanine (FePc) and nickel(II)   phthalocyanine (NiPc) adsorbed on the Au(111) surface are   reported. Both species provide images showing submolecular   structure. A particularly exciting aspect of this work is the   strong influence of the metal ion valence configuration on the   observed tunneling images. Unlike NiPc, wherein the central metal   appears as a hole in the molecular image, the iron ion in FePc is   the highest point (about 0.25 nm) in the molecular image. These   data are interpreted as indicating that the Fe(II) d6 system has   significant d orbital character near the Fermi energy while the   Ni(II) d8 system does not. This interpretation is consistent with   theoretical calculations that predict a large contribution of   iron d orbitals near the Fermi energy. The results reported here   are also fully consistent with our previous report of CoPc and   CuPc d orbital dependent images. An intriguing aspect of this   work is that it may be possible to chemically identify different   metal complexes simply by their appearance. Metal−organic complex   systems of this type may also be viewed as single molecular   electronic structures with different parts of the same molecule   behaving as insulator, conductor, or semiconductor.

      Address (URL): http://dx.doi.org/10.1021/jp9707448