15444-76-5Relevant academic research and scientific papers
TRANSITION METAL NITROSYLS AS NITROSYLATION AGENTS. VI. LIGAND REARRANGEMENT BETWEEN THE CARBONYLMANGANESE COMPLEXES + AND 10-n(PR3)n>, AND BIS(HALOGENODINITROSYLCOBALT)
Oltmanns, Peter,Rehder, Dieter
, p. 263 - 272 (1985)
The UV-induced nitrosylation of neutral and cationic carbonylmanganese compounds by 2 (X = Cl, Br, I) is a complex reaction involving the transfer of ligands usually considered as two- (CO and PR3, PR3 = PEtPh3, P(i-Bu)3, P(O-i-Pr)3), one- (X), and three-electron donors (NO).The cationic complexes are converted into MnBr2, while and its mono- and disubstituted phosphine derivatives readily yield (L = CO, THF, PR3), cis- (X = Cl, Br, I) and (L = CO, PR3).Reactivity and product spectrum vary considerably with the starting materials.The only reaction of preparative interest is the conversion of to by 2. 55Mn and 59Co NMR characteristics are reported.An optimized preparative route to and its 55Mn NMR spectroscopic feature is also described.
Relative Rates of H? Transfer from Transition-Metal Hydrides to Trityl Radicals
Eisenberg, David C.,Lawrie, Christophe J. C.,Moody, Anne E.,Norton, Jack R.
, p. 4888 - 4895 (2007/10/02)
The tris(p-tert-butylphenyl)methyl radical can be made in quantitative yield by treating a toluene solution of the corresponding bromide with copper powder. This radical abstracts H? from all the common transition-metal hydrides but does not stick to the resulting metalloradicals, so that the latter form metal-metal-bonded dimers. The rates of these H? transfer reactions have been measured directly in a stopped-flow apparatus. At 25°C the H? transfer rate constants vary from -1 s-1 for HMn(CO)4(PEtPh2) to 12000 M-1 s-1 for HFe(CO)2Cp. As a whole these rate constants show that the rates of these H? transfer reactions are substantially influenced by steric factors as well as by bond strengths.
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.
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.
STERIC EFFECTS OF PHOSPHINE LIGANDS ON THE PHOTOCHEMISTRY PF Mn2(CO)10
Busetto, C.,Mattucci, A. M.,Cernia, E. M.,Bertani, R.
, p. 183 - 188 (2007/10/02)
The photochemistry of Mn2(CO)10 in the presence of phosphine ligands has been investigated.Steric hindrance by the phosphine molecules influences the products of the photolysis reaction.With ethyldiphenylphosphine disubstituted symmetrical species are obt
