16800-46-7Relevant academic research and scientific papers
Electrochemical generation of 17-electron cation radicals from arene-M(CO)3 (M = Cr, Mo, W) and thiophene-Cr(CO)3 complexes in MeCN: Conventional cyclic voltammetric studies with digital simulation and microelectrode voltammetry in the absence of supporting electrolyte
Rourke, Frank,Gash, Rosslyn,Crayston, Joe A.
, p. 223 - 239 (1992)
One-electron electrochemical oxidation of arene-M(CO)3 (M = Cr, Mo, W) and thiophene-M(CO)3 complexes in acetonitrile produces 17-electron cations (MeCN)nM(CO)6-n+.Thus oxidation of LCr(CO)3, (L = C6H6, PhCl, PhNMe2, thiophene, 3-methylthiophene) in acetonitrile leads to a rapid follow-up reaction in which the intermediate (MeCN)3Cr(CO)3+ is detected by cyclic voltammetry.Oxidations in MeCN are not affected by redox catalysis, confirming a simple substitution mechanism.Increasing the concentration of the complex has no effect on the yield of MeCN substituted product, again ruling out bimolecular decomposition pathways.The reaction is very rapid and quite distinct from photochemical or thermal substitution of these complexes.Microelectrode steady-state voltammetry shows that all the arene complexes undergo two successive one-electron transfers in MeCN.Reproducible microelectrode voltammograms could only be obtained in MeCN in the absence of supporting electrolyte; addition of supporting electrolyte rapidly diminished the electrode response owing to electrode coating.
Electrochemical Detection of the Cr(CO3)3(MeCN)3+ Intermediate in the One-electron Oxidation of Arene- and Thiophene-chromiumtricarbonyl Complexes
Rourke, Frank,Crayston, Joe A.
, p. 1264 - 1266 (1988)
Oxidation of LCr(CO)3, (L=C6H6, C6H5Cl, dimethylaniline, thiophene, 3-methylthiophene) in acetonitrile leads to a rapid follow-up reaction in which the intermediate Cr(CO)3(MeCN)3+ is detected by cyclic voltammetry.
Heterobimetallic indenyl complexes. Synthesis and carbonylation reaction of anti-[Cr(CO)3-μ,η:η-indenyl-Ir(COD)]
Cecchetto, Pierluigi,Ceccon, Alberto,Gambaro, Alessandro,Santi, Saverio,Ganis, Paolo,Gobetto, Roberto,Valle, Giovanni,Venzo, Alfonso
, p. 752 - 762 (1998)
The reaction of the anti-[Cr(CO)3-μ,η:η-indenyl-Ir(COD)] (I) complex with an excess of CO in CH2Cl2 at 203 K produces quantitatively the η1-[η6-Cr(CO) 3-indenyl]-Ir(COD)(CO)2 intermediate which above 273 K converts into the fully carbonylated complex η1-[η6-Cr-(CO)3-indenyl]Ir(CO) 4; this in turn is stable up to 313 K. Carbonylation of the anti-[Cr-(CO)3-μ,η:η-indenyl-Ir(COE)2] analogue (II) gives the η1-[η6-Cr(CO)3-indenyl]-Ir(CO) 4 (VII) species in a single fast step. In contrast to the behavior of the corresponding rhodium complexes, for which η1 intermediates have never been observed and the aromatized substitution product is the stable product, the rearomatization of the cyclopentadienyl ring in iridium complexes to give the normal substitution product, viz., anti-[Cr(CO)3-μ,η:η-indenyl-Ir-(CO)2] (III) is a difficult process which takes place only on bubbling argon through the solution. The final product III is barely stable in solution. If the carbonylation is carried out using a blanket of CO over the solution of complexes I and II, viz., failing CO, the scarcely soluble iridium dimer [η6-Cr(CO)3-indenyl-η3-Ir(CO) 3]2 (IX) stable in the solid state is obtained, probably by dimerization of the unstable intermediate anti-[η6-Cr(CO)3-indenyl-η3-Ir(CO) 3] (X).
Alternating α-Olefin Distributions via Single and Double Insertions in Chromium-Catalyzed Ethylene Oligomerization
Tomov, Atanas K.,Nobbs, James D.,Chirinos, Juan J.,Saini, Prabhjot K.,Malinowski, Robert,Ho, Sarah K. Y.,Young, Craig T.,McGuinness, David S.,White, Andrew J. P.,Elsegood, Mark R. J.,Britovsek, George J. P.
, p. 510 - 522 (2017)
The catalytic oligomerization of ethylene with chromium-based complexes containing bis(benzimidazolemethyl)amine (BIMA) ligands results in alternating distributions of linear α-olefins (LAOs). Extremely high activities are obtained (>100 000 g mmol-1 h-1 bar-1) with N-alkyl-substituted BIMA ligands, whereas bulky groups on the central nitrogen or alternative central donors result in much lower activities. Variations in the ligand backbone, as well as methylation of the benzimidazole units, lead to reduction in activity. The alternating LAO distributions have been mathematically analyzed using second-order recurrence relations. The shape of the distributions is affected by ethylene pressure (1-4 bar) and by the cocatalyst to some degree. On the basis of the results and analysis presented herein, we propose that the alternating behavior originates from the ability of these chromium BIMA catalysts to undergo single as well as double ethylene insertion reactions. A minor second distribution (3 and the N-methyl BIMA ligand 2 have shown that deprotonation of the benzimidazole N-H units can occur, which suggests a change in coordination of the BIMA ligand under oligomerization conditions.
Structures and rearrangement mechanisms for some bicyclo[6.1.0]nona-2,4,6-triene complexes of chromium, molybdenum, and tungsten
Liotta Jr., Frank J.,Van Duyne, Gregory,Carpenter, Barry K.
, p. 1010 - 1023 (1987)
The structures of (bicyclo[6.1.0]nona-2,4,6-triene)tricarbonylmolybdenum and (endo-9-bromobicyclo-[3.1.0]nona-2,4,6-triene)tricarbonylmolybdenum have been investigated by X-ray crystallography. The first crystallized in the orthorhombic space group Pnma: a = 14.185, b = 10.417, c = 7.230 ?; Z = 4; 1143 reflections were measured, of which 756 were considered observed; the final structure had R = 0.115 and Rw = 0.137. The second complex crystallized in monoclinic space group P21/m: a = 8.740, b = 10.038, c = 13.742 ?; β = 85.9°; Z = 4; 1736 reflections were measured, of which 1494 were considered observed; R = 0.068 and Rw = 0.077. Both are shown to have geometries in which the cyclopropane ring is syn to the metal. In the 9-bromo complex only two of the three C=C bond are coordinated to the metal; the third coordination site is occupied by the halogen. The mechanism of thermal rearrangement of (bicyclo[6.1.0]nona-2,4,6-triene)tricarbonylmolybdenum to (bicyclo[4.2.1]nona-2,4,7-triene)tricarbonylmolybdenum has been investigated by deuterium-labeling and kinetic studies. A new, degenerate rearrangement of the starting complex has been discovered in the course of this investigation. Similar processes are shown to occur for the corresponding chromium and tungsten complexes. It is concluded that both types of rearrangement are sigmatropic processes in which the metal does not directly participate in cleavage of the C-C bond. The difference in thermal chemistry of the complexed and uncomplexed hydrocarbon is proposed to be due to selective inhibition of certain reaction pathways by the metal.
Spectroscopic studies of the complexes of acrylonitrile and acetonitrile with the carbonyls of chromium, molybdenum, and tungsten
Ross, Bonnie L.,Grasselli, Jeanette G.,Ritchey, William M.,Kaesz, Herbert D.
, p. 1023 - 1030 (1963)
Infrared and proton magnetic resonance spectroscopic studies of acrylonitrile complexes of the carbonyls of Cr, Mo, and W are used to assign the geometrical isomerism and manner of attachment of the ligand in these derivatives. Similar studies are also re
Electrode potentials and the thermodynamics of isodesmic reactions
Parker, Vernon D.,Handoo, Kishan L.,Roness, Frode,Tilset, Mats
, p. 7493 - 7498 (1991)
The free energies of isodesmic reactions can be calculated from appropriate electrode potential differences without the necessity of evaluating reference electrode potentials or the free energies of any chemical or physical processes. Class I rections inv
Aryl Oligogermanes as Ligands for Transition Metal Complexes
Zaitsev, Kirill V.,Lam, Kevin,Tafeenko, Viktor A.,Korlyukov, Alexander A.,Poleshchuk, Oleg Kh.
, p. 4911 - 4924 (2018/12/11)
The ligand properties of a series of aryl oligogermanes R3Ge-GeAr3, 3–7 [Me3Ge-GePh3 (3), Me3Ge-Ge(pTol)3 (4), Ph3Ge-GePh3 (5), (C6F5)3Ge-GePh3 (6), Ph3Ge-GeMe2GePh3 (7)] for the synthesis of transition metal carbonyl complexes such as R3Ge-GeAr2(R′C6H4-η6)M(CO)3 (M = Cr, 3a–7a; M = Mo, 3b; M = W, 3c) were investigated. The target complexes were obtained in moderate yields using several different synthetic approaches. The physicochemical properties of these new derivatives were investigated by IR, UV/Vis, NMR spectroscopy, electrochemistry, and DFT calculations. The molecular structures of 3c, 4a, and 5a were studied by single-crystal X-ray diffraction analysis. A comparative analysis of donor and acceptor properties of aryl oligogermanes as ligands for transition metal carbonyl complexes is reported.
On the coordination chemistry of corannulene, the smallest "buckybowl"
Stoddart, Michael W.,Brownie, John H.,Baird, Michael C.,Schmider, Hartmut L.
, p. 3440 - 3450 (2007/10/03)
A variety of methods, conventional and non-conventional, are used in attempts to prepare the compounds (η6-corannulene)M(CO) 3 (M = Cr, Mo, W), all unsuccessful. Conventional methods are also utilized in attempts to prepare the compound [CpFe(η6- corannulene)]PF6, but these result in mixtures of cationic CpFe(arene) complexes containing partially hydrogenated corannulene; similar results have been reported for other polyaromatic hydrocarbons. DFT calculations on the compound (η6-corannulene)Cr(CO)3 suggest that the (η6-corannulene)-Cr linkage is only a few kcal/mol weaker than the corresponding bond in (η6-benzene)Cr(CO)3, implying that failures in syntheses arise from kinetic, not thermodynamic problems.
Syntheses, characterization and structures of chromium group carbonyl complexes containing a multifunctional Ph2P(o-C6H4)CH=N(CH2) 2(o-C6H4N) ligand
Yang, Ching-Chao,Yeh, Wen-Yann,Lee, Gene-Hsiang,Peng, Shie-Ming
, p. 353 - 358 (2007/10/03)
Reactions of the phosphine-imine-pyridine-containing ligand Ph2P(o-C6H4)CH=N(CH2) 2(o-C6H4N) (PNN) with M(CO)3(NCMe)3 (M=Cr, Mo, W) produce the tridentate complexes fac-M(CO)3(η3-PNN). On the other hand, treating W(CO)4(NCMe)2 with PNN results in the bidentate complex W(CO)4(η2-PNN), which converts to fac-W(CO)3(η3-PNN) upon heating, but no facial→meridional isomerism is evidenced. The new compounds have been characterized by elemental analysis and mass, IR, and NMR spectroscopy. The molecular structures of W(CO)4(η2-PNN), fac-W(CO)3(η3-PNN) and fac-Mo(CO)3(η3-PNN) are determined by an X-ray diffraction study.
