- Reactions of N-phenyl-o-semiquinonediimine complexes of nickel and platinum with carbonyl-containing low-valence iron and rhenium compounds
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The reactions of o-semiquinonediimine complexes M[o-(NH)(NPh)C6H4]2 (M = Ni (1) or Pt (2)) with carbonyl-containing iron and rhenium compounds were studied. The reactions of complexes 1 or 2 with Fe(CO)5 afforde
- Reshetnikov,Talismanova,Sidorov,Nefedov,Eremenko,Moiseev
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- Cluster chemistry LIII. Preparation and some substitution reactions of bis(arylimido)triruthenium complexes: X-ray structures of Ru3(μ3-NPh)(μ3-NC6H4F-3)(CO)9 and Ru3(μ3-NPh)2(CO)8(L) (L=CNC6H3Me2-2,6 and PPh3)
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Azoarenes, ArN=NAr', react with Ru3(CO)12 to give Ru3(η3-NAr)(μ3-NAr')(CO)9 (Ar=Ph, Ar'=Ph, C6H4Me-3, C6H4CF3-3, C6H4F-3 (11), C6H4F-4; Ar=Ar'=C6H4Me-3) in moderate yields; for Ar=Ar'=Ph or C6H4Me-3, the mononuclear cyclometallated Ru(C6H3RN=NC6H4R-3)2(CO)2 (R=H or Me) were also obtained in low yield.Fe3(CO)12 and azobenzene afford Fe3(μ3-NPh)2(CO)9 in very low yield.An X-ray study of 11 confirms the structural assignments made on the basis of the spectroscopic measurements: an Ru3 triangle with a non-bonded Ru...Ru vector is capped on both sides by a μ3-arylimido moiety.Electron transfer-catalysed reactions with isocyanides, tertiary phosphines and phosphites proceed to give CO-substituted products in moderate yields: complexes Ru3(μ3-NPh)2(CO)8(L) (L=CNC6H3Me2-2,6 (15), PPh3 (16), P(OMe)3), 3-NPh)2(CO)8>2(μ-(PPh2)2C2) and Ru3(μ3-NPh)2(μ-LL)(CO)7 (LL=dppm, dppe) were obtained.X-ray structural studies of 15 and 16 show that the isocyanide ligand occupies an axial position, whereas the tertiary phosphine takes up an equatorial position, both on a terminal ruthenium atom.Crystal of 11, 15 and 16 crystallize in the monoclinic system with space group P21/n, a 11.496(2), b 14.020(2), c 15.735(2) Angstroem, β 99.43(1)o, Z=4 for 11; space group p21/n, a 11.933(2), b 18.952(2), c 14.370(4) Angstroem, β 100.29(2)o, Z=4 for 15; and space group Pc, a 17.507(3), b 11.657(2), c 19.518(4) Angstroem, β 100.41(2)o, Z=4 for 16.The structures were refined by least-squares methods and at convergence R=0.037, Rw=0.048 for 3653 statistically significant reflections for 11; R=0.041, Rw=0.046 for 3903 reflections for 15; and R=0.039, Rw=0.047 for 5291 reflections for 16.
- Bruce, Michael I.,Humphrey, Mark G.,Shawkataly, Omar bin,Snow, Michael R.,Tiekink, Edward R.T.
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- Azoalkane- and Nitrene-Bridged Carbonyl Metal Clusters of Iron and Ruthenium
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By using cluster buildup reactions, the new azoalkane-bridged clusters Ru3(CO)9(RN=NR) (3a, R = Me, 3b, R = Et), Fe2Ru(CO)9(EtN=NEt) (4), Ru4(CO)12(RN=NR) (5a, R = Me, 5n, R = Et), and FeRu3(CO)12(EtN=NEt) (6) were obtained.Upon attempts to prepare further such compounds, the N-N bond was cleaved resulting in nitrene-bridged clusters including the new compound Fe4(CO)11(Μ4-NEt)2 (9).Cluster buildup starting from Ru3(CO)9(μ3-NPh)2 resulted in Ru4(CO)11(μ4-NPh)2 (10) and FeRu3(CO)11(μ4-NPh)2 (11).The crystal structures of 5n and 9 as well as some reactions of the nitrene-bridged clusters are described.Key Words: Clusters, trinuclear and tetranuclear / Iron clusters / Ruthenium clusters / Azoalkane and nitrene bridging
- Hansert, Bernhard,Powell, Anne K.,Vahrenkamp, Heinrich
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p. 2697 - 2704
(2007/10/02)
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- Iron Carbonyl Induced o-Semidine Rearrangement of 1-Alkyl-2-aryldiazenes
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Key Words: Ironcarbonyl complexes / ortho-Metallation / o-Semidine rearrangement. Irradiation of pentacarbonyl iron in the presence of Me3C-N=N-Ar (Ar= phenyl, p-tolyl, p-CH3OC6H4) produces in the first step ortho-matallated complexes of the type Me3C-(CO)3 (2a-c, R=H, Me, MeO).In a thermal consecutive step these intermediates undergo an o-semidine rearrangement to Me3C-(H)RC6H3 (1a-c).The structure of 1a has been elucidated by X-ray structure analysis.Dynamic 13C-NMR spectra indicate restricted rotation of the Me3C group and hindered carbonyl scrambling for the latter and former complexes, respectively.
- Kisch, Horst,Reisser, Peter,Knoch, Falk
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p. 1143 - 1148
(2007/10/02)
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- Intramolecular conversion of an azoalkane ligand to two nitrene ligands on a triiron cluster
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The azoalkanes R2N2 (1; R = Et, Pr) have been reacted with Fe(CO)3(c-C8H14)2 or Fe3(CO)12 to yield the azoalkane complexes Fe2(CO)6(μ-η2-R2N 2) (2) and Fe3(CO)9(μ3-η2-R 2N2) (3). Thermolysis of the clusters 3 in solution has resulted in N-N cleavage without loss of CO to form the nitrene-bridged clusters Fe3(CO)9(μ3-NR)2 (4). From the reactions of azobenzene with the iron carbonyl starting materials only products resulting from N-N cleavage have been isolated. The crystal and molecular structures of Fe2(CO)6(μ-η2-Et2N 2) (2a), Fe3CO)9(μ3-η2-Et 2N2) (3a), and Fe3(CO)9(μ3-NEt)2 (4a) have been determined and refined to R values of 0.076, 0.046, and 0.058, respectively. (2a, monoclinic, P21/c, a = 7.541 (5) A?, b = 14.609 (5) A?, c = 14.205 (4) A?, β = 106.70 (4)°, Z = 4; 3a, monoclinic, P21/n, a = 8.860 (3) A?, b = 12.900 (2) A?, c = 16.147 (2) A?, β = 92.68 (2)°, Z = 4; 4a, orthorhombic, Pbca, a = 27.214 (8) A?, b = 12.391 (8) A?, c = 11.140 (6) A?, Z = 8). With use of a mixture of the N-Et and N-Pr compounds it was ascertained that the azoalkane-nitrene cleavage is intramolecular. It is inhibited under a CO atmosphere. Kinetic analysis has shown the reaction to be approximately first order with an activation energy of ca. 35 kcal/mol. The observations can be explained by CO elimination as the first step in the rearrangement. A molecular orbital analysis with EH calculations has led to two possible pathways. One is a simple rearrangement between seven-SEP nido-type square-based-pyramidal isomers and involves a reaction intermediate or transition state in which one nitrogen atom caps an Fe3N distorted square. The other one, which is fully consistent with the kinetic experiments, involves two intermediates with a six-SEP closo-type trigonal-bipyramidal structure; the first, resulting from CO loss and an R2N2 slippage, has an Fe2N pyramidal base, while the second, due to rearrangement and N-N cleavage, has an Fe3 pyramidal base. The final reaction step, readdition of a CO ligand, involves the opening of one Fe-Fe bond.
- Wucherer, Edward J.,Tasi, Miklos,Hansert, Bernhard,Powell, Anne K.,Garland, Maria-Theresa,Halet, Jean-Francois,Saillard, Jean-Yves,Vahrenkamp, Heinrich
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p. 3564 - 3572
(2008/10/08)
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