15529-62-1Relevant academic research and scientific papers
Metal to ligand charge-transfer photochemistry of metal-metal-bonded complexes. 10. Photochemical and electrochemical study of the electron-transfer reactions of Mn(CO)3(α-diimine)(L)? (L = N-, P-Donor) radicals formed by irradiation of (CO)5MnMn(CO)3(??-diimine) complexes in the presence of L
Van Der Graaf,Hofstra,Schilder,Rijkhoff,Stufkens,Van Der Linden
, p. 3668 - 3679 (2008/10/08)
This article describes the catalytic properties of Mn(CO)3(α-diimine)(L)? radicals, formed by irradiation with visible light of the complexes (CO)5MnMn(CO)3(α-diimine) (1) in the presence of L (L = N-, P-donor). The radicals initiate the catalytic disproportionation of complexes 1 in an electron transfer chain (ETC) reaction to give Mn(CO)5- and [Mn(CO)3(α-diimine)(L)]+. The efficiency of this reaction is low if L is a hard base; it increases for ligands having smaller cone angles and, for phosphines, higher basicities. The Mn(CO)3(α-diimine)(L)? radicals also reduce several of the cluster compounds M3(CO)12-x(PR3)x (M = Fe, Ru; x = 0-2) and catalyze the substitution of CO by PR3. In that case the efficiency of the reaction is mainly determined by the reduction potentials of the [Mn(CO)3(α-diimine)(PR3)]+ cation and the cluster. These potentials have been measured with cyclic voltammetry and differential pulse voltammetry.
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.
CARBONYLATION AND HYDROGENATION OF cis-CH3Mn(CO)4L, SUBSTITUTIONAL REACTIVITY OF cis-HMn(CO)4L, AND BINUCLEAR ELIMINATION BETWEEN cis-CH3Mn(CO)4P(OPh)3 AND cis-HMn(CO)4P(OPh)3 (L = CO, PPh3, P(OPh)3, PBu3 AND P(OMe)3)
Ruszczyk, Ronald J.,Huang, Bih-Lian,Atwood, Jim D.
, p. 205 - 212 (2007/10/02)
Several reactions of cis-CH3Mn(CO)4L and cis-HMn(CO)4L, have been investigated.The carbonylation of cis-CH3Mn(CO)4L (L = CO, P(OPh)3, P(OMe)3, and PBu3) shows a very small ligand effect, indicating a transition state that has little unsaturation.Reaction with H2 has very similar observed rate constants and activation parameters to the carbonylation.The hydrides, cis-HMn(CO)4L (L = P(OPh)3, PPh3 and PBu3), are remarkably unreactive toward substitution, requiring temperatures of 100 deg C.A radical mechanism is most likely.Reactions of cis-HMn(CO)4P(OPh)3 with cis-CH3Mn(CO)4P(OPh)3 and cis-HMn(CO)4PBu3 with CH3C(O)Mn(CO)5 occur at temperatures where methyl migration is readily established and the hydride complexes are unreactive.Thus methyl migration, followed by coordination to a bridging hydride, is indicated for these binuclear reductive elimination reactions.
