16457-30-0Relevant articles and documents
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.
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.
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.
