41133-30-6Relevant academic research and scientific papers
Formation of metal-metal bonds by ion-pair annihilation. Dimanganese carbonyls from manganate(-I) anions and manganese(I) cations
Lee,Kuchynka,Kochi
, p. 1886 - 1897 (2008/10/08)
The coupling of the anionic Mn(CO)5- and the cationic Mn(CO)6+ occurs upon mixing to afford the dimeric Mn2(CO)10 in essentially quantitative yields. Dimanganese decacarbonyl is formed with equal facility from the coupling of Mn(CO)5- with Mn(CO)5(py)+ and Mn(CO)5(NCMe)+. By way of contrast, the annihilation of Mn(CO)4PPh3- with Mn(CO)6+ yields a pair of homo dimers Mn2(CO)10 and Mn2(CO)8(PPh3)2 together with the cross dimer Mn2(CO)9PPh3. Extensive scrambling of the carbonylmanganese moieties also obtains with Mn(CO)4P(OPh)3- and Mn(CO)5PPh3+, as indicated by the production of Mn2(CO)8[P(OPh)3]2, Mn2(CO)8[P(OPh)3](PPh3), and Mn2(CO)8(PPh3)2 in more or less statistical amounts. These diverse Mn-Mn couplings can be accounted for by a generalized formulation (Scheme VI), in which the carbonylmanganese anions Mn(CO)4P- and the cations Mn(CO)5L+ undergo an initial electron transfer to produce Mn(CO)4P? and Mn(CO)5L?, respectively. The behaviors of these 17- and 19-electron radicals coincide with those independently generated in a previous study of the anodic oxidation of Mn(CO)4P- and the cathodic reduction of Mn(CO)5L+, respectively. The facile associative ligand substitution of 17-electron carbonylmanganese radicals by added phosphines provides compelling evidence for the interception of Mn(CO)4P? and its interconversion with 19-electron species in the course of ion-pair annihilation. The reactivity trend for the various ion pairs qualitatively parallels the driving force for electron transfer based on the oxidation and reduction potentials of Mn(CO)4P- and Mn(CO)5L+, respectively, in accord with the radical-pair mechanism in Scheme VI.
Mixed-metal dimers. 3. Substitution reactions of [(η5-C5H5)Fe(CO)2M(CO) 5] (M = Mn, Re) and the x-ray crystal structure determination of [(η5-C5H5)Fe(CO)2M(CO) 4(CNBu-t)] (M = Mn, Re)
Johnston, Peter,Hutchings, Graham J.,Denner, Louis,Boeyens, Jan C. A.,Coville, Neil J.
, p. 1292 - 1300 (2008/10/08)
The reaction between [(η5-C5H5)Fe(CO)2M(CO) 5] (M = Mn, 1; M = Re, 2) and L (L = t-BuNC, 2,6-Me2C6H3NC, PMePh2, P(OMe)3) under a variety of conditions is reported. Reaction between 2 and L (either thermally at 90°C, or in the presence of PdO as catalyst, or Me3NO) gives only the Re-substituted product [(η5-C5H5)Fe(CO)2Re(CO) 4L]. All attempts to synthesize the Fe-substituted complex, e.g., via the reaction between [(η5-C5H5)Fe(CO)(CNR)]+ and [Re(CO)5]-, failed. The thermal reaction between 1 and L yielded the Fe-substituted salts [(η5-C5H5)Fe(CO)L2]+ or [(η5-C5H5)FeL3]+. However, reaction of 1 with Me3NO followed by addition of L yielded either [(η5-C5H5)Fe(CO)2Mn(CO) 4(CNR)] (R = t-Bu 2,6-Me2C6H3NC) or [(η5-C5H5)Fe(CO)2]2 and [Mn2(CO)8L2] (L = P(OMe)3, PMePh2). Attempts to synthesize the Fe-substituted mixed-metal dimers failed. The new substituted mixed-metal dimers were completely characterized by IR NMR, and mass spectrometry as well as thermal and photochemical decomposition studies. The crystal and molecular structures of [(η5-C5H5)Fe(CO)2M(CO) 4(CNBu-t)] (M = Mn, 3; M = Re, 4) were determined. 3: space group P21/c, Z = 4, a = 8.715 (2) ?, b = 13.884 (2) ?, c = 15.579 (3) ?, β = 96.95 (2)°. 4: space group P21/n, a = 11.313 (2) ?, b = 11.055 (4) ?, c = 15.732 (3) ?, β = 107.03 (1)°. The structures were refined to R values of 0.050 and 0.037, respectively. In both structures the t-BuNC was attached to the non-Fe atom and in an equatorial site.
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.
Mechanisms of the carbon-hydrogen bond-forming binuclear reductive elimination reactions of benzyl- and hydridomanganese carbonyls
Nappa, Mario J.,Santi, Roberto,Halpern, Jack
, p. 34 - 41 (2008/10/08)
The reactions between RMn(CO)4L [R = p-MeOC6H4CH2; L = CO (1a), L = (p-MeOC6H4)3P (1c)] and HMn(CO)4L [L = CO (2a), L = (p-CH3OC6H4)s
