98703-44-7Relevant academic research and scientific papers
Conversion of η6-arylphosphine to η6-benzene complexes of molybdenum by use of strong acids to cleave the phosphorus-carbon bonds. The crystal and molecular structure of [Mo(H)(η6-C6H6)(PPh2CH 2CH2PPh2)(PPh2F)]BF4
Morris, Robert H.,Sawyer, Jeffery F.,Schweitzer, Caroline T.,Sella, Andrea
, p. 2099 - 2106 (2008/10/08)
The major products (～60%) in solution from the reaction between aqueous HBF4 or HF and Mo-(η6-PhPPh2){PPh2(CH2) nPPh2}(PPh3) [n = 1 (dppm, 1a), n = 2 (dppe, 1b), or n = 3 (dppp, 1c)] are the fluxional cations [Mo(H)(η6-C6H6){PPh2(CH 2)nPPh2}(PPh2OH)]+ (2a-c, respectively) and HPPh3+ (or [PPh3CMe2CH2C(O)Me]BF4 (4) if acetone is present). [MoO(F)(dppe)2]BF4 was identified in some reaction mixtures. Similar reactions of Mo(η6-PhPMePh){PPh2(CH2) nPPh2}(PMePh2) [n = 1, 1d; n = 2, 1e; n = 3, 1f] give [Mo(H)(η6-C6H6){PPh2(CH 2)nPPh2}(PMePhOH)]+ (2d-f, respectively) and HPMePh2+. The reaction of 1b or 1e with HBF4-Et2O under anhydrous conditions yields [Mo(H)(η6-C6H6)(dppe)(PRPhF)]BF4 (R = Ph, 3b, or R = Me, 3e) mixed with 2b or 2e. The structures are based on 31P, 1H, and 19F NMR spectra and spectral similarities to 3b whose structure has been determined by single-crystal X-ray diffraction [monoclinic, P21/c, a = 18.603 (5) A?, b = 15.774 (2) A?, c = 28.011 (8) A?, β = 100.41 (2)°, V = 8084 A?3, Dcalcd = 1.42 g cm-3 for Z = 8, R = 0.081 for 3266 reflections with I ≥ 3σ(I)]. Also reported is a preliminary structure of 4 [triclinic, P1, a = 10.122 (2) A?, b = 13.186 (3) A?, c = 18.889 (3) A?, α = 83.75 (1)°, β = 82.65 (1)°, γ = 76.99 (2)°, V = 2428 A?3, Dcalcd = 1.24 g cm-3 for Z = 4, R = 0.085 for 2416 reflections with I ≥ 3σ(I)] and some structural data for [MoO(F)(dppe)2]BF4 [monoclinic Cc, a = 9.921 (1) A?, b = 22.618 (4) A?, c = 21.313 (3) A?, β = 92.69 (2)°, V = 4777 A?3] which is isomorphous with [MoO(OH)(dppe)2]BF4. The reactions involve facile P-C bond cleavage and likely proceed by release of a PRPhXH+ group (X = F or OH) in an exo fashion from the ring since a crossover of PPh2 and PMePh fragments occurs when mixtures of complexes are treated with HBF4(aq); reaction with 1d and Mo(η6-PhPPh2)(dppe)(PMePh2) produces 2a, 2b, 2d, and 2e; reaction with 1b and 1f gives 2b, 2c, 2e, and 2f; reaction of 1b and Mo(η6-PhPMePh)-(PR2CH2CH2PR 2)(PMePh2) (R = p-tol, 1g) also gave the four crossover products. The crossover products do not exchange PPh2OH and PPhMeOH ligands.
THE INFLUENCE OF THE STERIC PROPERTIES OF THE LIGANDS PR2Ph AND L ON THE FORMATION AND PROPERTIES OF THE COMPLEXES Mo(η6-PhPR2)(L)(PPh2CH2CH2PPh2), R = Et, L = PPhEt2 and R = Ph, L = PPh3, PR'3, CO, CNR, N2, H2
Frizzell, James J.,Luck, Rudy L.,Morris, Robert H.,Peng, Shane H.
, p. 243 - 256 (2007/10/02)
The reduction of MoCl4(DPPE) (DPPE = PPh2CH2CH2PPH2) with Mg or Na/Hg in the presence of 2 PPhR2 under Ar results in the formation of the new complexes Mo(η6-PhPR2)(PPhR2)(DPPE) when R is Ph(Ia) or Et(II).No η6-PhPR2 complex is obtained when R is Me because this small ligand forms strong Mo-P ?-bonds; nor is one obtained for R = Cy because of too much steric crowding.The limits for η6-complexation can be quantified in terms of cone angle sums.Complex Ia is very similar to Mo(η6-PhPMePh)(PMePh2)3 (IIIa) in that both react at similar rates with a variety of small ligands L = PMePh2, PMe2Ph, PMe3, P(OMe)3, N2, CO, CNBut and H2 via dissocation of a labile ?-bonded ligand.Several other less crowded η6-arylphosphinemolybdenum complexes including II do not have labile ligands at 25 degC.The new complexes Mo(η6-PhPPh2)(L)(DPPE) have been characterized by 31P and 1H NMR, IR and gas uptake measurements.Ia has a higher affinity for H2 than IIIa possibly because Mo(η6-PhPPh2)(H)2(DPPE) adopts a non-fluxional trans-configuration.The 31P chemical shift of the η6-bonded ligand in 8 derivatives of Ia and 12 of IIIa correlate with the sum of cone angles of the three ?-bonded ligands in each complex.
