- Electron and bromine transfer reactions between metal carbonyl anions and metal carbonyl bromides. Crystal and molecular structure of dimeric indenyl molybdenum tricarbonyl
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Reactions of metal carbonyl anions with metal carbonyl halides proceed by two separate paths. When the reactant anion is a strong nucleophile, the halogen is transferred, resulting in a new metal carbonyl halide and a new metal carbonyl anion as intermediates. The ultimate products, in this case, are the homobimetallic complexes. In cases where the reactant metal carbonyl anion is a poor nucleophile, a single electron transfer occurs, leading to the two homobimetallic complexes and to the heterobimetallic complex. Halide effects and possible indenyl effects are examined. The complex [Mo(indenyl)(CO)3]2 crystallizes in the noncentrosymmetric orthorhombic space group P212121 (No. 19) with a = 7.3572(7) ?, b = 14.4539(12) ?, c = 19.983(2) ?, V = 2125.0(4) ?3, and Z = 4. Diffraction data were collected on a Siemens R3m/V diffractometer for 2θ = 5-45° (Mo Kα), and the structure was solved and refined to R = 3.21% and Rw = 3.23% for all 2786 independent reflections (R = 2.26% and Rw = 2.81% for those 2314 reflections with |Fo|> 6σ(|Fo|). The complex is held together by a Mo-Mo single bond (Mo(1)-Mo(2) = 3.251(1) ?), and has Mo-CO distances ranging from 1.956(6) to 1.988(7) ?, averaging 1.970 ± 0.016 A. Molybdenum-carbon distances to the η5-indenyl rings range from 2.300(7) to 2.427(6) ? for Mo(1) and 2.306(7) to 2.430(6) ? for Mo(2).
- Striejewske, William S.,See, Ronald F.,Churchill, Melvyn Rowen,Atwood, Jim D.
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p. 4413 - 4419
(2008/10/08)
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- Steric and Electronic Factors That Control Two-Electron Processes between Metal Carbonyl Cations and Anions
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Reactions of metal carbonyl cations (Mn(CO)6(+), Re(CO)6(+), Mn(CO)5PPh3(+), Mn(CO)4(PPh3)2(+), Mn(CO)5PEt3(+), Mn(CO)5PPh2Me(+), Re(CO)5PPh3(+), and CpFe(CO)3(+)) with metal carbonyl anions (Co(CO)3PPh3(-), Co(CO)4(-), Mn(CO)5(-), Mn(CO)4PPh3(-), Mn(CO)4PEt3(-), Mn(CO)4PPh2Me(-), Mn(CO)3(PPh3)2(-), CpFe(CO)2(-), Re(CO)5(-), and Re(CO)4PPh3(-)) are reported.Peak potentials are reported for all ions, and nucleophilicites (as measured by reaction with MeI) are reported for the anions.Reaction of any metal carbonyl cation with any metal carbonyl anion leads ultimately to binuclear products, which are the thermodynamic products.The binuclear products are formed by single-electron transfer.In over half of the reactions between metal carbonyl cations and anions, a two-electron change results in a new metal carbonyl cation and anion.The two-electron change may be considered mechanistically as a CO(2+) transfer with the more nucleophilic of the two anions retaining the CO(2+).The kinetic and thermodynamic driving forces and the suggested mechanism are examined.
- Zhen, Yueqian,Feighery, William G.,Lai, Chung-Kung,Atwood, Jim D.
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p. 7832 - 7837
(2007/10/02)
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- Bimetallic anionic formyl complexes: Synthesis and properties
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Three bimetallic anionic formyl complexes, Li+[Mn2(CO)9(CHO)]- (2), Li+[ReMn(CO)9(CHO)]- (3), and Li+[cis-Re2(CO)9(CHO)]- (4), are prepared by the reaction of Li(C2H5)3BH with the corresponding neutral metal carbonyl dimers MM′(CO)10. Whereas 2 has a half-life of ca. 8 min at room temperature, 4 is stable for days and is easily isolated as a THF solvate. When 2-4 are treated with electrophiles such as benzaldehyde, Fe(CO)5, and n-octyl iodide, hydride transfer occurs to give benzyl alcohol (after protonation), Li+[Fe(CO)4(CHO)]-, and octane, respectively. Heterobimetallic formyl 3 is a weaker hydride donor than 2 and 4. Reaction of 4 with CH3I gives CH4 (ca. 50%). However, complex reactions occur when 2 and 4 are treated with CH3SO3F and strong acids, contrary to our original report of CH4 and H2 evolution. Formyl 2 is stabilized by added (C2H5)3B and decomposes disproportionatively to Mn2(CO)10 (0.5 equiv), Li+[Mn(CO)5]- (1.0 equiv), and H2 (0.5 equiv). An initial Mn-Mn bond cleavage step is proposed. The only characterizable product from the thermolysis of 4 is Re2(CO)10, but photolysis gives Li+[Re2(CO)9(H)]-. When K+[Re2(CO)9(CHO)]- is treated with 1 equiv of K(sec-C4H9)3BH, reduction to formaldehyde (21%) and K2[Re2(CO)9] (92%) occurs.
- Tam, Wilson,Marsi, Marianne,Gladysz
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p. 1413 - 1421
(2008/10/08)
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- Characterization of MnTc(CO)10 and TcRe(CO)10
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The heteronuclear decacarbonyls of MnTc and TcRe have been synthesized and characterized according to the infrared and mass spectra. Optimum conditions have been established for their preparation and purification, which may be applicable to the production of mixed-metal carbonyls in general.
- Michels, Gary D.,Svec, Harry J.
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p. 3445 - 3447
(2008/10/08)
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