88271-82-3Relevant academic research and scientific papers
Substituted metal carbonyls. 26.1 One-step synthesis, structures, NMR, and dynamic laser-light scattering of Re2(μ-OMe)2[μ-Ph2P(CH2) nPPh2](CO)6 (n = 1-4)
Low, Pauline M. N.,Yong, Yuk Lin,Yan, Yaw Kai,Hor, T. S. Andy,Lam, Sik-Lok,Chan, Kam Kwong,Wu, Chi,Au-Yeung, Steve C. F.,Wen, Yuh-Sheng,Liu, Ling-Kang
, p. 1369 - 1374 (2008/10/08)
Oxidative decarbonylation of Re2(CO)10 by Me3NO in a mixture of THF and MeOH followed by addition of alkyl-chained diphosphine Ph2P(CH2)nPPh2 (PP) (n = 1-4) gives Re2(μ-OMe)2-(μ-PP)(CO)6 in 34, 29, 28, and 10% yields, respectively. This methanolytic oxidation across the Re-Re bond provides a general and one-step route for the synthesis of these dirhenium hexacarbonyl complexes with diphosphine and methoxo bridges. The molecular structure of Re2(μ-OMe)2(μ-Ph2PCH2PPh 2)(CO)6 was determined by single-crystal X-ray diffraction analysis. It contains two fac-[Re(CO)3] moieties bridged by dppm and two methoxo ligands. The {Re2O2} core is significantly more planar than that in the Fe(C5H4PPh2)2 analogue. That such a dinuclear core is maintained in spite of the different steric demands of the different bridging diphosphines illustrates the great geometric tolerance of the bridging methoxo groups. The fluxionality of the dppm, dppe, and dppp complexes has been studied and compared by molecular modeling and solution 1H NMR spectroscopy. Dynamic laser-light scattering (DLS) shows that the dppe complex aggregates in CH2Cl2 to form small clusters with an average radius of ～370 nm. The use of a combination of DLS and NMR in organometallic chemistry is unprecedented.
Bridging phosphorus ligand substituted dirhenium octacarbonyl compounds. Preparation and reactions with water and methanol
Lee, Kang-Wook,Pennington, William T.,Cordes, A. Wallace,Brown, Theodore L.
, p. 404 - 413 (2008/10/08)
The bridging ligand substituted dirhenium octacarbonyl compounds, 1,2-eq,eq-Re2(CO)8(L-L), L-L = bis(dimethylphosphino)methane (dmpm), bis(diphenylphosphino)methane (dppm), bis(dimethylphosphino)ethane (dmpe), and bis(diphenylphosphino)ethane, (dppe), have been synthesized in high yield from L-L and (μ-H)(μ-CH=CHC4H9)Re2(CO)8. Re2(CO)8(dppe) and Re2(CO)8(dmpe) undergo rapid intramolecular exchange involving a twist about the Re-Re axis. The relative photochemical reaction rates of Re2(CO)8(L-L) with water or methanol are in the order dppe > dmpe > dppm > dmpm. The major products are (μ-H)(μ-OR)Re2(CO)6(L-L) and (μ-OR)2Re2(CO)6(L-L) (R = H or CH3). However, these products could be isolated from the reaction mixtures only for the dmpm and dppm compounds. The structure of (μ-H)(μ-OH)Re2(CO)6(dppm) was determined by conventional crystallographic techniques by using Mo Kα X-rays. The crystals belong to the triclinic space group P1 with a = 10.904 (2) A?, b = 11.099 (2) A?, c = 14.646 (2) A?, α = 84.69 (1)°, β = 83.18 (1)°, γ = 60.69 (1)°, and Z = 2. RF = 0.031 for 5547 reflections having 2θ 6σ(I). The molecular structure consists of two Re(CO)3 units bridged by hydrido, hydroxo, and dppm ligands. The Re-Re distance is 3.030 (1) A?, the Re-H distances of the H-bridge are 1.84 (8) and 2.00 (8) A?, and the Re-O distances are 2.177 (5) and 2.160 (5) A?. Formation of (μ-H)(μ-OR)Re2(CO)6(L-L) and other products in the reactions is thought to proceed via two pathways, one involving metal-metal bond rupture and the other involving CO dissociation. The stability of (μ-H)(μ-OH)Re2-(CO)6(dppm) or (μ-H)(μ-OH)Re2(CO)6(dmpm) is ascribable to the presence of the relatively rigid bridging phosphine ligand that maintains the metal atoms in close proximity. Reactions of (μ-H)(μ-OR)Re2(CO)6(L-L) and (μ-OR)2Re2(CO)6(L-L) with dry HCl leads to formation of (μ-H)(μ-Cl)Re2(CO)6(L-L) and (μ-Cl)2Re2(CO)6(L-L), respectively.
