The syntheses and characterization of Os(II) and Ru(II)/Os(II) bimetallic complexes with dipyrido(2,3-a:3?2?j)phenazine (dpop? and the bridging ligand 2,3,5,6-tetra(2-pyridyl)-pyrazine (tppz)

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• 作者：Roberto Padilla ; Ronald R. Ruminski ; ^{rruminsk@uccs.edu} ; Vivina A. Meredith McGinley ; Preston B. Williams
• 关键词：Os(II) complexes ; Synthesis ; Electrochemistry ; NMR ; Absorption spectra ; Characterization
• 刊名：Polyhedron
• 出版年：2012
• 出版时间：9 February, 2012
• 年：2012
• 卷：33
• 期：1
• 页码：158-165
• 全文大小：899 K

文摘

The syntheses of mixed ligand mono metallic [Os(dpop?(tppz)](PF₆)₂, homo-bimetallic [(dpop?Os(tppz)Os(dpop?](PF₆)₄ and mixed metal bimetallic [(dpop?Ru(tppz)Os(dpop?](PF₆)₄ (dpop?#xA0;= dipyrido(2,3-a:3?2?j)phenazine; tppz = 2,3,5,6-tetra(2-pyridyl)-pyrazine) complexes is described. NMR spectroscopy was used to confirm pure products were separated from similar species. The ¹H NMR spectrum for the mixed metal Ru/Os bimetallic complex ion reflects additive components of the Ru/Ru and Os/Os bimetallic species. Proton resonances on Ru(II) bonded ligands are upfield from Os(II) bonded ligands. Cyclic voltammetry for the Os/Os and Ru/Os bimetallic complex ions show the reversible tppz^0/? reduction at less negative potential than the dpop?sup>0/? reduction. Additionally, the [(dpop?Os(tppz)Os(dpop?]⁴⁺ ion displays reductive coupling of the remote terminal dpop?ligands that is not observed in the bimetallic Ru/Ru species, indicating larger metal-ligand mixing occurs for Os(II) than Ru(II) complexes. The UV-Vis electronic absorption spectra for all complex ions show intense Os(d¦Ð) ?#xA0;dpop?¦Ð^{?/sup>) and Os(d¦Ð) ?#xA0;tppz(¦Ð?/sup>) MLCT transitions in the visible spectrum with IL transitions in the UV.}