- Synthesis and crystal structure of the [Re2(CH 3COO)2Cl4((CH3) 2NCOCH3)2] complex
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Compound [Re2(CH3COO)2Cl 4((CH3)2NCOCH3)2] is synthesized. The influence of parameters of the hydrothermal synthesis under elevated pressure on the yield of a target product and its molecular structure and physicochemical properties is studied. In the neutral complex with cis-arrangement of the bridging acetate and terminal chloride ligands with respect to the multiply bonded Re26+ complex-forming center, the Re-Re bond length is 2.2418(3) A. Dimethylacetamide molecules are in the axial positions, the Re-O bond lengths being 2.304(3) and 2.321(4) A. The influence of the donor ability of the axial substituents in analogous structures of the rhenium(III) binuclear clusters on the Re-Re and Re-Lax bond lengths is analyzed.
- Mel'nik,Filinchuk,Shtemenko
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p. 786 - 791
(2008/10/09)
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- Reactions of the polyhydrides Re2H8(PPh3)4 and ReH7(PPh3)2 with acetic acid/acetic anhydride. Isolation and characterization of the rhenium(I) carbonyl complexes Re(O2CCH3)(CO)1+x(PPh3) 3-x (x = 0, 1) and the homoleptic dirhenium(III) ...
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Full title: Reactions of the polyhydrides Re2H8(PPh3)4 and ReH7(PPh3)2 with acetic acid/acetic anhydride. Isolation and characterization of the rhenium(I) carbonyl complexes Re(O2CCH3)(CO)1+x(PPh3) 3-x (x = 0, 1) and the homoleptic dirhenium(III) carboxylate complex Re2(μ-O2CCH3)4(O 2CCH3)2. The dirhenium octahydride Re2H8(PPh3)4 reacts with acetic acid/acetic anhydride mixtures in dichlorobenzene to give the homoleptic acetate complex Re2(μ-O2CCH3)4(O 2CCH3)2 as the major product together with small quantities of the carbonyl complex Re(O2CCH3)(CO)2(PPh3)2. The related reaction with propionic acid/propionic anhydride gives only Re(O2CC2H5)-(CO)2(PPh 3)2 in very low yield. Treatment of ReH7(PPh3)2 with these same acid/anhydride mixtures in THF, in the presence of PPh3, affords yellow Re(O2CR)(CO)(PPh3)3 (R = CH3, C2H5) in high yield. Solutions of these complexes in 0.1 M n-Bu4NPF6/CH2Cl2 show a reversible couple in their cyclic voltammograms associated with a one-electron oxidation to their 17-electron cations. Chemical oxidation of Re(O2CR)(CO)(PPh3)3 to the paramagnetic, orange salts [Re(O2CR)(CO)(PPh3)3]PF6 has been accomplished by using [(η5-C5H5)2Fe]PF6 in acetone. The acetate complex [Re(O2CCH3)(CO)(PPh3)3]PF 6·THF has been characterized structurally by X-ray crystallography. Crystal data at 20°C: space group Pnma, a = 15.785 (4) A?, b = 22.577 (3) A?, c = 23.824 (3) A?, V = 5656 (5) A?3, and Z = 4. The structure was refined to R = 0.033 and Rw = 0.040 for 2600 data with F2 > 3.0σ(F2).
- Cameron, Charles J.,Fanwick, Phillip E.,Leeaphon, Malee,Walton, Richard A.
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p. 1101 - 1104
(2008/10/08)
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- Studies of the photoinduced ligand substitution reactions of [Re(CNxyl)6]+ (xyl = 2,6-dimethylphenyl) in the presence of halide ions
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Irradiation of [Re(CNxyl)6]+ with UV light at 20°C in dichloromethane and in the presence of halide ions yields complexes of the type Re(CNxyl)5X, where X = Cl, Br, or I. The quantum yields are quite respectable, φp = 0.2-0.3, and isolated product yields are in the range of 30-40%. The photoproducts have been characterized by spectroscopic methods and, in the case of the new derivatives Re(CNxyl)5Cl and Re(CNxyl)5Br, by elemental microanalyses. The magnitudes of the quantum yields suggest that ligand substitution occurs by a dissociative mechanism involving a reactive d-d excited state.
- Stacy, Nathan E.,Conner, Kay A.,McMillin, David R.,Walton, Richard A.
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p. 3649 - 3652
(2008/10/08)
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- Formation of mononuclear and dinuclear halide complexes of rhenium from reactions of the polyhydrides Re2H8(PR3)4 and ReH7(PR3)2 with allyl halides and other halogen-containing reagents
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Reactions occur between ReH7(PPh3)2 and the allyl halides C3H5X (X = Cl, Br, and I) to afford the rhenium(IV) salts (Ph3PC3H5)2ReX6; H2 and propene (plus a trace of propane) are the principal gaseous products. Allyl thiocyanate reacts in an analogous fashion. The pentahydride complexes ReH5(PPh3)2L (L = C6H11NH2 and C5H10NH) are also converted to (Ph3PC3H5)2ReCl6, H2, and propene by allyl chloride. The dinuclear core of Re2H8(PPh3)4 is preserved upon reaction with allyl chloride and bromide to give the quadruply bonded dirhenium species (Ph3PC3H5)2Re2X 8 (X = Cl or Br) plus H2 and propene. In contrast to this, the reaction with allyl iodide results in the cleavage of the Re-Re bond and the formation of (Ph3PC3H5)2ReI6. The mononuclear polyhydride complex ReH7(PPh3)2 also reacts with the chlorocarbons CCl4, CHCl3, CH2Cl2, Me3CCl, and C6H5Cl to produce trans-ReCl4(PPh3)2 with the concomitant evolution of H2 and some hydrocarbons. The treatment of Re2H8(PPh3)4 with gaseous hydrogen chloride in methanol is unusual in that crystals of the mixed rhenium(III)-rhenium(IV) salt (Ph3PH)2Re2Cl8-5(Ph 3PH)ReCl5(PPh3) are formed. The course of these reactions is discussed, and the properties of the rhenium-containing complexes are described.
- Allison, Joe D.,Cameron, Charles J.,Walton, Richard A.
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p. 1599 - 1603
(2008/10/08)
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