K W Hipps - Scanning Tunneling Microscopy of Metal Phthalocyanines:  d7 and d9 Cases

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      Publication Details (including relevant citation   information):

      Lu, Xing, Hipps, K. W., Wang, X. D., Mazur, Ursula Journal of   the American Chemical Society 1996  118 (30) 7197-7202

      Abstract: Scanning tunneling microscopy (STM)   images of cobalt(II) phthalocyanine (CoPc), copper(II)   phthalocyanine (CuPc), and mixtures of the two adsorbed on the   Au(111) face are reported. Based upon the stability and ease of   obtaining molecular images, CoPc appears to adsorb more strongly   than CuPc on Au(111), but both species provide images showing   submolecular structure. The mixed CoPc and CuPc films also   provide high-quality images showing details of the internal   structure of the metal phthalocyanine. A particularly exciting   aspect of this work is the strong influence of the metal ion   valence configuration on the observed tunneling images. Unlike   CuPc, wherein the central metal appears as a hole in the   molecular image, the cobalt atom in CoPc is the highest point   (about 0.3 nm) in the molecular image. These data are interpreted   as indicating that the Co(II) d7 system has significant d-orbital   character near the Fermi energy while the Cu(II) d9 system does   not. This interpretation is consistent with theoretical   calculations that predict a large contribution of cobalt   d-orbitals near the Fermi energy, and with inelastic electron   tunneling spectra that show d-orbital-related bands within 1 eV   of the Fermi energy. An intriguing aspect of this work is that it   may be possible to chemically identify the different metal   phthalocyanines simply by their appearance. This can be used to   advantage in the study of surface diffusion, 2-d sublimation, and   the surface thermodynamics and kinetics of adlayer formation.

      Address (URL): http://dx.doi.org/10.1021/ja960874e