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Synthesis and characterisation of ruthenium octaethylporphyrin complexes

University of British Columbia

The synthesis and characterisation of some higher valent Ru octaethylporphyrin complexes are discussed. These complexes, Ru(OEP)(X)(X’) (X=X'=Br,Cl and X=SbF₆,X'=THF) are of the oxidation state IV and III, respectively, with either a triplet d⁴, S=l intermediate spin ground state (for X=X'=Br, CI) or a d⁵, S=1/2 low spin (for X=SbF₆,X'=THF) ground state. The alternative Ru[sup III] or Ru[sup II] π-cation radical formulations are ruled out. The first Ru-X bond frequencies (X=Br,179 cm⁻¹;X=Cl,289 cm⁻¹ KBr) in Ru-porphyrin systems are assigned. The ¹H NMR data indicate that contact contributions dominate the isotropic shifts but dipolar relaxation is responsible for the relaxation of the resonances observed. The metal-porphyrin π-bonding arises from ligand-to-metal charge transfer in all three complexes and the Ru[sup III]:(SbF₆) complex likely has a μ-fluoro bridge with μsb-F = 650 cm⁻¹, Nujol. The simple preparative reactions have high yields (>80%) and the stability of these complexes make them excellent precursors for further chemistry in high-valent ruthenium porphyrins.

Text

2010-06-30

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http://hdl.handle.net/2429/26073

Chemistry

University of British Columbia

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