26743-81-7Relevant articles and documents
Mixed-valence dimolybdenum complexes containing hard oxo and soft carbonyl ligands: synthesis, structure, and electrochemistry of Mo2(O)(CO)2(μ-κ2-S(CH2)nS)2(κ2-diphosphine)
Haque, Mohd. Rezaul,Ghosh, Shishir,Rahman, Md. Matiar,Siddiquee, Tasneem A.,Nesterov, Vladimir N.,Richmond, Michael G.,Hogarth, Graeme,Kabir, Shariff E.
, p. 10102 - 10112 (2018)
Mixed-valence dimolybdenum complexes Mo2(O)(CO)2{μ-κ2-S(CH2)nS}2(κ2-Ph2P(CH2)mPPh2) (n = 2, 3; m = 1, 2) (1-4) have been synthesized from one-pot reactions of fac-Mo(CO)3(NCMe)3 and dithiols, HS(CH2)nSH, in the presence of diphosphines. The dimolybdenum framework is supported by two thiolate bridges, with one molybdenum carrying a terminal oxo ligand and the second two carbonyls. The dppm (m = 1) products exist as a pair of diastereomers differing in the relative orientation of the two carbonyls (cis and trans) at the Mo(CO)2(dppm) center, while dppe (m = 2) complexes are found solely as the trans isomers. Small amounts of Mo(CO){κ3-S(CH2CH2S)2}(κ2-dppe) (5) also result from the reaction using HS(CH2)2SH and dppe. The bonding in isomers of 1-4 has been computationally explored by DFT calculations, trans diastereomers being computed to be more stable than the corresponding pair of cis diastereomers for all. The calculations confirm the existence of Mo= O and Mo-Mo bond orders and suggest that the new dimeric compounds are best viewed as Mo(v)-Mo(i) mixed-valence systems. The electrochemical properties of 1 have been investigated by CV and show a reversible one-electron reduction associated with the Mo(v) centre, while two closely spaced irreversible oxidation waves are tentatively assigned to oxidation of the Mo(i) centre of the two isomers as supported by DFT calculations.
Reactivity of [Mo(CO)3(NCMe)3] towards pyrimidine-2-thiol (pymSH) and thiophenol (PhSH) in the presence of phosphine auxiliaries: Synthesis of mono- and dinuclear complexes bearing κ2 and μ,κ2-pymS coordination
Roknuzzaman,Abedin, S.M. Tareque,Haque, Mohd. Rezaul,Ghosh, Shishir,Tocher, Derek A.,Richmond, Michael G.,Kabir, Shariff E.
, p. 55 - 63 (2019/03/11)
The reaction of [Mo(CO)3(NCMe)3] with added thiol in the presence of a phosphine auxiliary has been investigated. Treatment of [Mo(CO)3(NCMe)3] with pyrimidine-2-thiol (pymSH) and PPh3 at 60 °C in MeC
Synthesis, structure and bonding of new mono- and dinuclear molybdenum complexes containing pyridine-2-thiolate (pyS) and different P-donors
Haque, Mohd. Rezaul,Ghosh, Shishir,Hogarth, Graeme,Richmond, Michael G.,Kabir, Shariff E.
, p. 150 - 157 (2015/06/22)
Three new molybdenum complexes have been synthesized from one-pot reactions between Mo(CO)3(NCMe)3 and pyridine-2-thiol (pySH) in the presence of different P-donors. Reaction with P(OMe)3 in MeCN at ca. 55 °C gives Mo(CO)
Rapid synthesis of Group VI carbonyl complexes by coupling borohydride catalysis and microwave heating
Birdwhistell, Kurt R.,Schulz, Brian E.,Dizon, Paula M.
, p. 69 - 71 (2013/01/15)
Several Group VI tetracarbonyl phosphine and tertiary amine complexes [M(CO)4 L2, M = Cr, Mo, W, L2 = 2PPh 3, dppm, dppe, dppp, dppb, bpy, phen, dppf] were synthesized in minutes in the microwave at moderate temperature, atmospheric pressure, and utilizing NaBH4 as a catalyst. The reactions were optimized by careful solvent selection. The octahedral complexes were isolated in percent yields ranging from 17 to 95. The lower temperatures, shorter reaction times, benign solvents, and lower pressures as compared to the traditional thermal syntheses provide a rapid, eco-friendly synthetic route to these common Group VI complexes.
Organometallic chemistry in a conventional microwave oven: The facile synthesis of group 6 carbonyl complexes
Ardon, Michael,Hogarth, Graeme,Oscroft, Daniel T.W.
, p. 2429 - 2435 (2007/10/03)
Syntheses proceeding by reflux may be improved, accelerated and simplified, by carrying out the reaction in a modified conventional microwave oven. To demonstrate the potential of this method, the synthesis of over 20 group 6 organometallic compounds is reported. Hexacarbonyls, most notably Mo(CO)6, react with a range of mono, and bi, and tridentate ligands in a modified conventional microwave oven. They generally proceed without an inert atmosphere, yields are high and reaction times are short. For example, cis -[Mo(CO)4(dppe)] is prepared in >95% yield in 20 min. Reaction of Mo(CO)6 with dicyclopentadiene affords a simple one-step synthesis of [CpMo(CO)3]2 in >90% yield, which reacts further with alkynes in toluene to produce dimetallatetrahedrane derivatives, [Cp2Mo2(CO)4 (μ-RC2R)]; presumably via the in situ formation of air-sensitive [CpMo(CO)2]2. Dimolybdenum tetra-acetate is also prepared in 48% yield in 45 min, however, this reaction requires an inert atmosphere. While W(CO)6 reacts rapidly with amines to give cis diamine adducts in high yields, direct reactions with phosphines are not so clean. Bis(phosphine) complexes are, however, cleanly formed when a small amount of piperidine is added to the reaction mixture, presumably via the bis(piperidine) complex cis-[W(CO)4(pip)2]. Reactions with Cr(CO)6 generally require an inert atmosphere and proceed less cleanly, although the important synthon [Cr(CO)5 Cl][NEt4] was prepared in 30 min (74% yield), while [(η6-C6H5OMe)Cr(CO)3] can be prepared in 45% after 4 h.
Microwave-assisted synthesis of group 6 (Cr, Mo, W) zerovalent organometallic carbonyl compounds
VanAtta, Sky L.,Duclos, Brian A.,Green, David B.
, p. 2397 - 2399 (2008/10/08)
The microwave-assisted synthesis of a series of compounds of the form ML(CO)4 (M = Cr, Mo, W; L = en, bipy, dppm, dppe), results in the reduction of reaction times and an increase in yields over previously published syntheses. Reaction times are reduced by a factor of 5 to over 500.
Ligand substitution kinetics in M(CO)4 (η2:2-1,5-cyclooctadiene) complexes (M=Cr, Mo, W) - Substitution of 1,5-cyclooctadiene by bis(diphenylphosphino)alkanes
Kayran, Ceyhan,Kozanoglu, Ferda,Oezkar, Saim,Saldamli, Saltuk,Tekkaya, Aysin,Kreiter, Cornelius G.
, p. 229 - 236 (2008/10/08)
The thermal substitution kinetics of 1,5-cyclooctadiene (COD) by bis(diphenylphosphino)alkanes (PP), (C6H5)2P(CH2)nP(C 6H5)2 (n = 1, 2, 3) in M(CO)4(η2:2-COD) complexes (M = Cr, Mo, W), were studied by quantitative FT-IR spectroscopy. The reaction rate exhibits first-order dependence on the concentration of the starting complex, and the observed rate constant depends on the concentration of the leaving COD ligand and on the concentration and the nature of the entering PP ligand. In the proposed mechanism, the rate determining step is the cleavage of one metal-olefin bond of the COD ligand. A rate-law is derived from the proposed mechanism. The evaluation of the kinetic data gives the activation parameters which support an associative mechanism in the transition states. Both the observed rate constant and the activation parameters show little variation with the chain length of the diphosphine ligand.
Ligand substitution kinetics in M(CO)4(η2:2-norbornadiene) complexes (M=Cr, Mo, W): Displacement of norbornadiene by bis(diphenylphosphino)alkanes
Tekkaya, Aysin,Oezkar, Saim
, p. 208 - 216 (2007/10/03)
The thermal substitution kinetics of norbornadiene (NBD) by bis(diphenylphosphino)alkanes (PP), (C6H5)2P(CH2)nP(C 6H5)2 (n=1, 2, 3) in M(CO)4(η2:2-NBD) complexes (M=Cr, Mo, W), were studied by quantitative FT-IR spectroscopy. The reaction rate exhibits first-order dependence on the concentration of the starting complex, and the observed rate constant depends on the concentration of the leaving NBD ligand and on the concentration and the nature of the entering PP ligand. In the proposed mechanism there are two competing initial steps: an associative reaction involving the attachment of the entering PP ligand to the transition metal center and a dissociative reaction involving the stepwise detachment of the diolefin ligand from the transition metal center. A rate law is derived from the proposed mechanism. The activation parameters are obtained from the evaluation of the kinetic data. It is found that at higher concentrations of the entering ligand, the associative path is dominant, while at lower concentrations the contribution of the dissociative path becomes significant. Both the observed rate constant and the activation parameters show noticeable variation with the chain length of the diphosphine ligand.
Investigation of complexes of diphenylphosphine derivatives by thermal and other physicochemical methods of analyses
Zayed,Arifien,Hassan
, p. 205 - 212 (2008/10/08)
Six heteroatomic complexes of diphenylphosphine derivatives with heavy metals (Ni, Pd, Pt, Mo and W) were prepared and subjected to elemental spectral and thermal analyses. The different physicochemical methods used indicated the formulae [NiCl2(dppm)], [PtCl2(dppm)] and [Mo(CO)4(dppm)] (dppm = bis(diphenylphosphine)methane, the dppm in these complexes behaving as a bidentate ligand), [Pd(CN)2(dppm)2] (in which the dppm behaves as a monodentate ligand), [W(CO)4(dppe)2] and [Mo(CO)4(dppe)2] (dppe = 1,1-bis(diphenylphosphine)ethene, the dppe in these complexes behaving as a bidentate ligand). The thermal analyses (DTA and TG) confirmed these structures. The results of spectral and thermal analyses were compared.
Neighboring metal-induced oxidative addition in conjunction with a hydride trap: Formation of [(η5-MeC5H4)Fe(CO)(μ-η 1:-PPh2CH2PPh2)(μ-H)M(CO) 4] (M = W, Mo)
Liu,Wen, Yuh-Sheng,Liu, Ling-Kang
, p. 155 - 157 (2008/10/08)
The reaction of(η4-MeC5H5)Fe(CO)2(η 1-dppm), 1, with M(CO)3L3 produced (η 5c?5-I?€a?5C?4)N?a?(€ I?)(i?-c?1:c?1-dppm)(μ-H)M(CO)4, 3 (L3 = (C2Hsub
