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Synthesis and Characterization of Heterobinuclear Cyclometalated Complexes Containing Small Bite Angle Bridging Ligand

Ghazfar, Reza | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43621 (03)
  4. University: Sharif University Of Technology
  5. Department: Chemistry
  6. Advisor(s): Jamali, Sirous
  7. Abstract:
  8. The heteronuclear complexes [MePt(bhq)(μ-dppy)Au(PPh3)]PF6, 2, [MePt(bhq)(dppy)Tl]PF6, 3 and [Me2Pt2(bhq)2(dppy)2Tl]PF6, 4 in which bhq=benzo{h}quinoline and dppy=2-diphenylphosphinopyridine, were prepared by reaction of the mononuclear complex [MePt(bhq)(dppy)] 1 with 1 equivAuCl(PPh3), 1equiv TlPF6 and 1/2 equiv TlPF6 respectively. All the complexes were fully characterized using multinuclear NMR spectroscopy and ESI-MS spectrometry. In addition molecular structures of complexes 2 and 3 in solid state have been determined by X-ray crystallography that shown strong dative bonds between platinum and gold or thallium atoms. As shown by ESI-MS spectrometry, the Pt-Au bond in complex 2 undergoes dissociation while the Pt-Tl bonds in 3 and 4 retained in the gas phase. It has been shown previously that the bridging acetone molecule in butterfly cluster complex 5 [Me2Pt2(bhq)2(μ-dppy)2Ag2(μ-acetone)](BF4)2 dissociated from the cluster complex in solution and a dynamic equilibrium is suggested to be established between the planar and butterfly skeletal geometries.Computational study of complex 5 shows that optimized structure for complex 5 without bridging acetone molecule has planar metal core geometry with strong argentophilic interaction. Spectroscopy and crystal structure of 2shows that bridging dppy ligand swapped between platinum and gold atoms. Photophysical study of the bi- and multi-heteronuclear complexes, 2 -5 hase been carried out and compared with photophysical properties of the mononuclear complex 1. The platinum-thallium complexes 3 and 4 show absorption bands corresponding with a mixed ligand to metal and ligand to ligand charge transfer transitions while platinum-silver complex 5 shows an absorption band corresponding metal-metal to ligand charge transfer transition
  9. Keywords:
  10. Platinum ; Metal-Metal Bond ; Heteronuclear Complexes

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