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Isomer Effect on the Structure and Chemical Reactivity of Diruthenium Complexes. Synthesis and Characterization of the (4,0), (3,1), and (2,2) Trans Isomers of Ru 2 (F 5 ap) 4 Cl and Ru 2 (F 5 ap) 4 (C⋮CC 6 H 5 ) 2 Where F 5 ap Is the 2-(2,3,4,5,6-Pentafluoroanilino)pyridinate Anion

1997; American Chemical Society; Volume: 36; Issue: 24 Linguagem: Inglês

10.1021/ic9602658

1520-510X

John L. Bear, Yulan Li, Baocheng Han, Eric Van Caemelbecke, Karl M. Kadish,

Synthesis and characterization of novel inorganic/organometallic compounds

The syntheses and characterization of the (4,0), (3,1), and (2,2) trans isomers of Ru2(F5ap)4Cl and Ru2(F5ap)4(C⋮CC6H5)2 are reported where F5ap is the 2-(2,3,4,5,6-pentafluoroanilino)pyridinate anion. The (4,0), (3,1), and (2,2) trans isomers of Ru2(F5ap)4Cl were separated on a silica gel column following the reaction between Ru2(CH3COO)4Cl and molten HF5ap under argon. The (4,0), (3,1), and (2,2) trans isomers of Ru2(F5ap)4(C⋮CC6H5)2 were obtained by reaction of their respective isomer of Ru2(F5ap)4Cl with LiC⋮CC6H5 in THF at room temperature. The three isomers of Ru2(F5ap)4Cl and Ru2(F5ap)4(C⋮CC6H5)2 were characterized by 1H and 19F NMR, ESR, and IR spectroscopy, mass spectrometry and electrochemistry. Each RuIIRuIII isomer of Ru2(F5ap)4Cl is paramagnetic and undergoes two oxidations and one reduction in CH2Cl2, 0.1 M TBAP while each RuIII2 isomer of Ru2(F5ap)4(C⋮CC6H5)2 is diamagnetic and undergoes one oxidation and two reductions under the same solution conditions. All of the redox processes are reversible and involve metal-centered one-electron transfers. The singly reduced products of the (4,0), (3,1), and (2,2) trans isomers of Ru2(F5ap)4(C⋮CC6H5)2 were electrogenerated and display ESR signals consistent with the presence of a single unpaired electron. Molecular structures of the three isomers of Ru2(F5ap)4(C⋮CC6H5)2 were also determined. The (4,0) isomer crystallizes in the monoclinic space group P21/c with a = 23.436(6) Å, b = 20.640(6) Å, c = 23.504(6) Å, β = 105.82(2)°, and Z = 8, while the (3,1) isomer crystallizes in the monoclinic space group P21/n with a = 15.621(3) Å, b = 16.427(3) Å, c = 21.166(5) Å, β = 93.91(2)°, and Z = 4. The (2,2) trans isomer crystallizes in the triclinic space group P1̄ with a = 12.819(5) Å, b = 13.390(4) Å, c = 17.827(5) Å, α = 85.04(2)°, β = 72.66(2)°, γ = 68.47(2)°, and Z = 2. The average Ru−Ru bond distances in the (4,0), (3,1), and (2,2) trans isomers of Ru2(F5ap)4(C⋮CC6H5)2 are 2.450(1), 2.475(1), and 2.473(1) Å, respectively.