16457-30-0Relevant academic research and scientific papers
Hydride participation in electron transfer processes between metal carbonyl anions and cations
Harrigan, Marcus J.,Atwood, Jim D.
, p. 846 - 849 (2008/10/09)
Kinetic studies of selected metal carbonyl anions establish their reactivity as nucleophiles or for electron transfer. The iron species, [HFe(CO)3L]- (L = CO, PPh3), behave as metal-centered nucleophiles when reacted with [M(CO)6]+ (M = Mn, Re). Determination of the deuterium kinetic isotope ratio from kinetic studies of [HFe(CO)4]- and [DFe(CO)4]-, kH/kD = 2.8, indicates primary isotope effects for reaction with Mn(CO)6+. Initial products from transfer of a CO and back transfer of two electrons are observed in some cases. For Re-(CO)6+ exclusive formation of HRe(CO)5 as a rhenium product strongly indicates a hydrogen transfer mechanism.
Transition-metal hydrides and carbonyl anions as ligands toward a Pt centre in rhenium-platinum triangular clusters: A qualitative order of 'thermodynamic nucleophilicity'
Bergamo, Mirka,Beringhelli, Tiziana,Ciani, Gianfranco,D'Alfonso, Giuseppe,Moret, Massimo,Sironi, Angelo
, p. 291 - 303 (2008/10/08)
Six novel mixed-metal spiked-triangle complexes [Re2Pt(μ-H)2(CO)9{X}] have been obtained. The metallo-ligands X bound to the Pt vertex are either transition-metal hydrides, such as HMn(CO)5, HRe(CO)4(PPh3), HRe(CO)3(PPh3)2, or carbonyl anions, such as [Mn(CO)5]-, [WCp(CO)3]- and [Co(CO)4]-. Two main synthetic routes have been used to prepare these complexes: (i) replacement of the labile ligand 1,5-cyclooctadiene (COD) of [Re2Pt(μ-H)2(CO)8(COD)] with CO and X; (ii) substitution of the labile 'ligand' HRe(CO)5 in [Re2Pt(μ-H)2(CO)9{HRe(CO)5}] by the ligands X. The neutral species [Re2PtMn(μ-H)3(CO)14] has been obtained by protonation of [Re2Pt(μ-H)2(CO)9{Mn(CO)5}] -. Variable temperature 1H NMR investigations showed that it exists in solution as two isomers a and b, likely differing in the location of one hydride, a having the structure [Re2Pt(μ-H)2(CO)9{HMn(CO)5}], and b the structure [Re2Pt(μ-H)3(CO)9{Mn(CO)5}]. The ligand HMn(CO)5 of a shows a high lability, being in fast exchange with free [HMn(CO)5] even at 193 K. At higher temperature interconversion between the two isomers and exchange between the hydrides bound to Pt in b is observed. The treatment of [Re2Pt(μ-H)2(CO)9{WCp(CO)3}] - with strong acids failed to give the protonated derivative. The strong nucleophile [FeCp(CO)2]- reacted with [Re2Pt(μ-H)2(CO)9{HRe(CO)5}] as a Broensted base rather than as a nucleophile, giving deprotonation instead of substitution of the labile HRe(CO)5 ligand bound to Pt. The complex [Re2Pt(μ-H)2(CO)9{HRe(CO) 4(PPh3)}] has been characterised by X-ray single crystal analysis. It crystallises in the monoclinic space group P21/c (No. 14) with a=9.229(3), b=30.700(8), c=12.915(3) A, β=98.05(2)°, V=3623(2) A3 and Z=4. A series of displacement reactions of the type [Re2Pt(μ-H)2(CO)9{X}]+X′ ? [Re2Pt(μ-H)2(CO)9(X′)] + X allowed the following qualitative order of affinity of the metallo-ligands X for the Pt atom (a scale of 'thermodynamic nucleophilicity') to be established: [Re(CO)5]- > [HRe2(CO)9]-≈[Mn(CO)5] ->[WCp(CO)3]->[Co(CO)4] -> [HRe(CO)4(PPh3)]>[HRe(CO)3(PPh 3)2]>[HRe(CO)5]>[HMn(CO) 5]>[HWCp(CO)3].
Low-temperature neutron diffraction study of HMn2Re(CO)14 and studies of a metal metal exchange equilibrium that converts HMn2Re(CO)14 into HMnRe2(CO)14
Bullock, R. Morris,Brammer, Lee,Schultz, Arthur J.,Albinati, Alberto,Koetzle, Thomas F.
, p. 5125 - 5130 (2007/10/02)
The crystal and molecular structure of (CO)5Re(μ-H)Mn(CO)4Mn(CO)5, prepared from reaction of Mn2-(CO)9(η1-tolualdehyde) with HRe(CO)5, has been determined from neutron diffraction measurements at 15 K: unit-cell constants, a = 9.145 (1) A?, b = 15.557 (3) A?, c = 14.040 (3) A?, β = 106.60 (2)°, monoclinic, space group P21/n, Z = 4, V = 1914.2 (6) A?3, R(F2) = 0.110 for 4859 reflections with F02 ≥ 3σ(F02) and (sin θ/λ)max = 1.054 A?-1. The Re-H distance (1.827 (4) A?) is longer than the Mn-H distance (1.719 (5) A?). Spectroscopic and crystallographic data indicate that a small amount (～9%) of (CO)5Re(μ-H)Mn(CO)4Re(CO)5 has cocrystallized with the major component. Further evidence for the identity of (CO)5Re(μ-H)Mn(CO)4Re(CO)5 comes from an independent synthesis by a known route. A mechanism is proposed that accounts for the formation of (CO)5Re(μ-H)Mn(CO)4Re(CO)5 from the reaction of (CO)5Re(μ-H)Mn(CO)4Mn(CO)5 with HRe(CO)5. The equilibrium constant for the metal-metal exchange equilibrium, (CO)5Re(μ-H)Mn(CO)4Mn(CO)5 + HRe(CO)5 = (CO)5Re(μ-H)Mn(CO)4Re(CO)5 + HMn(CO)5, has been determined; Keq = 1.00 ± 0.05 at 22 °C in C6D6.
DIRHENIUM COMPLEXES CONTAINING LINKED DIPHENYLACETYLENE MOLECULES FROM THE PHOTOREACTION OF H3Re3(CO)12 WITH PhCPhC. CRYSTAL AND MOLECULAR STRUCTURES OF Re2(CO)5(C4Ph4)(C2Ph2) AND Re2(CO)4(C6Ph6)(C2Ph2)*0.5 HEXANE
Pourreau, Daniel B.,Whittle, Robert R.,Geoffroy, Gregory L.
, p. 333 - 346 (2007/10/02)
Photolysis of H3Re3(CO)12 in presence of diphenylacetylene (DPA) yields Re2(CO)10, HRe(CO)5, and the three alkyne complexes Re2(CO)7(DPA)2, Re2(CO)5(C4Ph4)(DPA) (4) and Re2(CO)4(C6Ph6)(DPA) (3), the latter two which were shown by X-ray crystallography to possess linked DPA ligands.The complex Re2(CO)5(C4Ph4)(DPA) crystallizes in the triclinic space group P (No.2) with a 11.277(3), b 12.301(3), c 14.851(3) Angstroem, α 97.37(2), β 104.68(2), γ 104.49(2) deg, V 1889(2) Angstroem3, and Z = 2.The structure was refined using the 4548 reflections with I 2?(I) to give final residuals of R = 0.031 and Rw = 0.041.Complex 4 possesses a rhenacyclopentadiene group bonded to the second rhenium atom and an η2-DPA ligand bound to the rhenium atom of the metallacycle.The complex Re2(CO)4(C6Ph6)(DPA) crystallizes in the monoclinic space group P21/c (No.14) with a 17.048(4), b 16.676(2), c 18.569(4) Angstroem, β 106,70(2) deg, V 5056(3) Angstroem3, and Z = 4.For the 3568 reflections with I 2?(I), the structure refined to R = 0.078 and Rw = 0.074.Three of the DPA molecules in Re2(CO)4(C6Ph6)(DPA) are linked together to form a fly-over bridge between the two rhenium atoms.The fourth DPA molecules is η2-bound to one rhenium center.
Bimetallic anionic formyl complexes: Synthesis and properties
Tam, Wilson,Marsi, Marianne,Gladysz
, p. 1413 - 1421 (2008/10/08)
Three bimetallic anionic formyl complexes, Li+[Mn2(CO)9(CHO)]- (2), Li+[ReMn(CO)9(CHO)]- (3), and Li+[cis-Re2(CO)9(CHO)]- (4), are prepared by the reaction of Li(C2H5)3BH with the corresponding neutral metal carbonyl dimers MM′(CO)10. Whereas 2 has a half-life of ca. 8 min at room temperature, 4 is stable for days and is easily isolated as a THF solvate. When 2-4 are treated with electrophiles such as benzaldehyde, Fe(CO)5, and n-octyl iodide, hydride transfer occurs to give benzyl alcohol (after protonation), Li+[Fe(CO)4(CHO)]-, and octane, respectively. Heterobimetallic formyl 3 is a weaker hydride donor than 2 and 4. Reaction of 4 with CH3I gives CH4 (ca. 50%). However, complex reactions occur when 2 and 4 are treated with CH3SO3F and strong acids, contrary to our original report of CH4 and H2 evolution. Formyl 2 is stabilized by added (C2H5)3B and decomposes disproportionatively to Mn2(CO)10 (0.5 equiv), Li+[Mn(CO)5]- (1.0 equiv), and H2 (0.5 equiv). An initial Mn-Mn bond cleavage step is proposed. The only characterizable product from the thermolysis of 4 is Re2(CO)10, but photolysis gives Li+[Re2(CO)9(H)]-. When K+[Re2(CO)9(CHO)]- is treated with 1 equiv of K(sec-C4H9)3BH, reduction to formaldehyde (21%) and K2[Re2(CO)9] (92%) occurs.
Photochemical Reaction of Dirhenium Decacarbonyl with Water
Gard, David R.,Brown, Theodore L.
, p. 6340 - 6347 (2007/10/02)
The photochemical reaction of Re2(CO)10 with H2O in THF and other solvents has been studied, with use of radiation of varying wavelength.The initial reaction leads to Re2(CO)9(OH2), formed upon irradiation at 313 nm.This product is shown to form via a pri
