64490-77-3Relevant academic research and scientific papers
Reactions of chloro complexes of dimolybdenum(II) containing quadruple metal-metal bonds with bidentate tertiary phosphines (C6H5)2P(CH2)n,P(C 6H5)2 (n = 1-3) and (C6H5)2P(CH2)2As(C 6H5)2 in alcohol media
Cole, Nancy F.,Derringer, Daniel R.,Fiore, Elizabeth A.,Knoechel, Donald J.,Schmitt, Rebecca K.,Smith, Thomas J.
, p. 1978 - 1982 (2008/10/08)
The reactions of K4Mo2Cl8 with the bidentate tertiary phosphines bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1-(diphenylphosphino)-2-(diphenylarsino)ethane (arphos), and 1,3-bis(diphenylphosphino)propane (dppp) in methanol, ethanol, and 1-propanol produce complexes of the type Mo2Cl4(LL)2. The reactions of Mo2Cl4(py)4 and Mo2Cl4(P(n-Pr)3)4 with dppe and dppp have also been explored. The only form of Mo2Cl4(dppm)2 isolated from the three alcoholic solvents is the species known to have a bridging dppm structure. In refluxing methanol both Mo2Cl84- and Mo2Cl4(py)4 yield α-Mo2Cl4(LL)2 complexes (LL = dppe, dppp), whose spectral properties are consistent with structures containing chelating phosphine ligands. In 1-propanol these reactants lead to β-Mo2Cl4(LL)2 complexes (LL = dppe, dppp), which are believed to exhibit structures with a trans disposition of donor atoms in the MoCl2P2 moiety and with the phosphine bridging the Mo2 unit. Reaction in ethanol gives rise to mixtures. Under refluxing conditions only β-Mo2Cl4(arphos)2 is produced in pure or nearly pure form from K4Mo2Cl8 and arphos, whereas in methanol at lower temperatures mixtures of α and β isomers result from reaction with (NH4)5[Mo2Cl8]Cl·H 2O. The chelating isomers are converted to the bridging forms on reflux in 1-propanol or prolonged reflux in methanol (arphos, dppp). These results indicate a thermodynamic stabilization of the β-Mo2Cl4(LL)2 species in the higher alcohols while the α isomers are the kinetically favored products in methanol. Although the reaction of Mo2Cl4(P(n-Pr)3)4 and dppe in methanol yields a mixture of α- and β-Mo2Cl4(dppe)2, the reaction with dppp produces Mo2Cl4(P(n-Pr)3)2(dppp), whose spectral properties are similar to those of the known Mo2Cl4(PR3)4 species.
Preparation of the crystalline β (bridged) isomer of Mo2Cl4(dppe)2 and determination of its crystal structure
Agaskar, Pradyot A.,Cotton, F. Albert
, p. 3383 - 3387 (2008/10/08)
It has been found that the α and β isomers of Mo2Cl4(dppe)2, dppe = (C6H5)2PCH2CH2P(C 6H5)2, can be prepared by the reaction of Mo2(O2CCF3)4 with (CH3)3SiCl and dppe. The isomer obtained is controlled by reaction conditions, primarily the solvent. It has also been found possible to obtain both isomers in crystalline form. The crystal structure of the β isomer, in which the dppe ligands bridge the Mo-4Mo unit, has been determined. It forms crystals in space group P21/n with a = 23.103 (45) A?, b = 13.258 (75) A?, c = 16.792 (62) A?, β = 107.19(7)°, V = 4913 (11) A?3, and Z = 4. The midpoints of the Mo-Mo quadruple bonds reside on a set of general positions. At each position there are two orientations, a principal one (87%) and a minor one (13%). In the principal orientation the helical molecule consists of two fused rings with chair conformations and a mean angle of twist about the Mo-Mo axis of 30.5°. In the minor orientation, the fused rings have twist conformations and the sense of the helix about the Mo-Mo bond is opposite to the one in the principal molecule with an angle of 27.7°. In the principal molecule, the Mo-Mo distance is 2.183 (3) A? and the mean Mo-P and Mo-Cl distances are 2.579 (8) and 2.385 (7) A?, respectively.
Synthetic Pathways in Binuclear Molybdenum Chemistry: μ-Acetato-, Chloro-, and Tertiary Phosphine Derivatives; X-Ray Structure Determination of trans-n3)(μ-O2CMe)>2>
Green, Malcolm L. H.,Parkin, Gerard,Bashkin, Jim,Fail, John,Prout, Keith
, p. 2519 - 2526 (2007/10/02)
The reaction between 2> and SiMe3Cl in the presence of a variety of donor ligands L n3, or Ph2P(CH2)nPPh2, where n = 1 or 2> yields binuclear compounds such as 2> or .The products may vary according to the stoicheiometry of the reaction.The new compounds described are 2>, 2>, isomers of 2>, trans-n3)(μ-OCOMe)>2>, and .Interconversion of some of these compounds by ligand-replacement reactions is also demonstrated.The crystal structure of trans-n3)(μ-OCOMe)>2> is described; the crystals are monoclinic, space group P21/n1 with a = 14.969(2), b = 15.146(2), c = 8.920(2) Angstroem, β = 105.14(1)deg, and Z = 2.Refinement converged with R = 0.048, R' = 0.063, for 1 762 observed reflections 3?(I)>.The Mo-Mo separation is 2.099(1) Angstroem.The presence of isomers of the various compounds is demonstrated from the hydrogen-1 n.m.r. spectra.
