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- Steen, Robert O., et al.
(författare)
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The role of isomeric effects on the luminescence lifetimes and electrochemistry of oligothienyl-bridged dinuclear tris(2,2′-bipyridine) ruthenium(II) complexes
- 2008
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-0682. ; :11, s. 1784-1794
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Tidskriftsartikel (refereegranskat)abstract
- The luminescence lifetimes (in CH 3CN at room temperature) and electrochemical potentials (in CH 3CN) of a range of mono- and bis(bidentate) 2,2′-bipyridine-capped oligothiophene-bridged Ru II complexes based on the 6-(2-thienyl)-2,2′-bipyridine and 4-(2-thienyl)-2,2′-bipyridine motifs have been measured. The redox potentials occurred in a very narrow range and showed only small shifts from that of [Ru(bpy) 3] 2+, which indicates that the inductive effects of the substituents on the 2,2′-bipyridine ligands are very similar across this series. In the complexes that incorporated a bithiophene moiety the oxidation of the bithienyl group occurred at higher potentials than the metal-centered Ru III/II oxidation. No or very weak interaction between the metal cores in the dinuclear complexes was observed. It was found that the luminescence lifetimes of the complexes where the attachment point of the oligothiophene bridge is in the 4-position of a 2,2′-bipyridine ligand were extended compared to [Ru(bpy) 3] 2+, whereas the luminescence was very short-lived (<30 ns) or completely quenched in the complexes where the oligothiophene bridge was attached in the 6-position. The difference in lifetimes is probably due to steric interactions between the thienyl bridge and the auxiliary bipyridyl ligands, resulting in disturbances in coordination symmetry of the metal core.
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| 3. |
- Angus-Dunne, Sarah J., et al.
(författare)
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Metallocene and organo-main group trifluoromethanesulfonates
- 2006
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Ingår i: Transition metal chemistry (Weinheim). - : Springer Science and Business Media LLC. - 0340-4285 .- 1572-901X. ; 31:2, s. 268-275
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Tidskriftsartikel (refereegranskat)abstract
- The substituted metallocene compounds Cp2M(OSO 2CF3)2 (Cp=η5-C 5H5; M = Ti, Zr, Hf, Nb, Mo), CpTi(OSO2CF 3)3 • 0.75(1,2-dimethoxyethane), and the organo-main group compounds (C6H5)3M′(OSO 2CF3) (M′=Si, Ge), (C6H5) 2Sn(OSO2CF3)2 and (C 6H5)3Sb(OSO2CF3) 2, were synthesized from the corresponding chloride or bromide compounds and silver trifluoromethanesulfonate (triflate) and characterized spectroscopically, including a detailed analysis of their IR spectra. Triflate coordination is typically monodentate, but CpTi(OSO2CF 3)3 • 0.75(1,2-dimethoxyethane) and the organo-germanium triflate show evidence of bidentate CF3SO 3 - ligands and are likely to have polymeric structures. Conductance measurements in nitromethane, acetone and acetonitrile have demonstrated the ease of triflate substitution, with a limited kinetic study of acetone solvation of the Ti and Hf compounds supporting an associative pathway. Three new catalysts for the polymerization of tetrahydrofuran, Cp 2HfCl2/Ag(OSO2CF3), CpTiCl 3/Ag(OSO2CF3) and (C6H 5)2SiCl2/Ag(OSO2CF3), are also reported.
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