42965-72-0Relevant academic research and scientific papers
Manganese(0) radicals and the reduction of cationic carbonyl complexes: Selectivity in the ligand dissociation from 19-electron species
Kuchynka,Amatore,Kochi
, p. 4087 - 4097 (2008/10/08)
Products and stoichiometry for the cathodic reduction of the series of carbonylmanganese(I) cations Mn(CO)5L+, where L - CO, MeCN, pyridine, and various phosphines, derive from 1-electron transfer to generate the 19-electron radicals Mn(CO)5L? as reactive intermediates. The CO derivative Mn(CO)6+ affords mainly the anionic Mn(CO)5- by the facile ligand dissociation of Mn(CO)6? to the 17-electron radical Mn(CO)5? followed by reduction. The acetonitrile and pyridine derivatives Mn(CO)5NCMe+ and Mn(CO)5py+ produce high yields of the dimer Mn2(CO)10 by an unusual and highly selective heterolytic coupling of Mn(CO)5- and the reactant cation. Structural factors involved in the conversion of 19-electron radicals to their 17-electron counterparts are examined in the reduction of the graded series of phosphine derivatives Mn(CO)5P+, where P = triaryl- and trialkylphosphines. The formation of the hydridomanganese complexes HMn(CO)4P is ascribed to hydrogen atom transfer to the 19-electron radicals Mn(CO)5P? followed by extrusion of CO. The lability of carbonylmanganese radicals is underscored by rapid ligand substitution to afford the bis(phosphine) byproduct HMn(CO)3P2.
Binuclear iron-manganese acetyl and hydride complexes from the reactions of Cp(CO)2FePPh2 with CH3Mn(CO)5 and HMn(CO)5
Rosen, Richard P.,Hoke, Jeffrey B.,Whittle, Robert R.,Geoffroy, Gregory L.,Hutchinson, John P.,Zubieta, Jon A.
, p. 846 - 855 (2008/10/08)
The new heterobimetallic bridging acetyl complex Cp(CO)Fe(μ-C(O)CH3)(μ-PPh2)Mn(CO)4 (1) has been prepared by the reaction of CH3Mn(CO)5 with PPh2FeCp(CO)2. It has been spectroscopically and structurally characterized. Complex 1 crystallizes in the space group P1 with a = 11.485 (4) A?, b = 12.989 (4) A?, c = 16.932 (5) A?, α = 68.22 (2)°, β = 87.17 (2)°, γ = 88.88 (2)°, V = 2342 (1) A?, and Z = 4. The structure has been refined to R = 0.044 and Rw = 0.042 for the 3353 reflections with I > 3σ(I). The acetyl ligand bridges the Fe and Mn centers with the acetyl carbon attached to Fe and the oxygen bound to Mn. The nonbonded metals (Fe?Mn = 3.718 A?) are also bridged by the μ-PPh2 ligand. The chemistry of complex 1 has been examined with HBF4, [(CH3)3O]BF4, [Ph3C]BF4, H2, PPh2Me, and MeLi, and these reactions are discussed. Reaction of HMn(CO)5 with PPh2FeCp(CO)2 gives the bridging hydride complex Cp(CO)Fe(μ-H)(μ-PPh2)Mn(CO)4 (3), which has also been structurally characterized. It crystallizes in the monoclinic space group P21/n with a = 10.795 (4) A?, b = 13.931 (2) A?, c = 14.497 (4) A?, β = 102.08 (3)°, V = 2132 (2) A?3, and Z = 4. The structure has been refined for the 2412 reflections with I > 2σ(I) to R = 0.057 and Rw = 0.063. The Fe and Mn atoms are separated by 2.806 (1) A? and are bridged by the hydride and the μ-PPh2 ligand. The Fe atom is further coordinated by the Cp ligand and one CO, and Mn has four additional CO ligands.
