108796-72-1Relevant academic research and scientific papers
Low-temperature photochemistry of [Fe2(CO)7(L)] (L = bpy, phen) and [Fe2(CO)6(L′)] (L′ = R-PyCa, R-DAB) complexes. Stabilization of [Fe2(CO)7(R-PyCa)]
Van Dijk, Hans K.,Stufkens, Derk J.,Oskam, Ad,Rotteveel, Marc,Heijdenrijk, Dick
, p. 1665 - 1672 (2008/10/08)
The low-temperature photochemistry of [Fe2(CO)7(L)] (L = 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen)) and [Fe2(CO)6(L′)] (L′ = pyridine-2-carbaldehyde imine (R-PyCa), 1,4-diaza-1,3-butadiene (R-DAB)) complexes in 2-MeTHF is described. Irradiation of the [Fe2(CO)7(L)] complexes into the low-energy MLCT band causes the substitution of CO by nucleophiles, such as phosphines and N-donor ligands. The structures of the photoproducts appear to depend on the electronic properties of the substituting ligand. The crystal structure of one such a photoproduct, viz., the complex [Fe2(CO)6(bpy)(P(n-Bu)3)] has been determined. The crystals are triclinic, space group P1, with a = 10.727 (1) ?, b = 14.517 (2) ?, c = 10.306 (2) ?, α = 97.30 (1)°, β = 96.53 (1)°, γ = 74.13 (2)°, V = 1525.9 (7) ?3, and Z = 2. A total of 2425 intensities above the 3σ(I) level were used to refine the structure to a final R value of 0.057. The Fe-C bond trans to the phosphine ligand in this complex (2.244 (6) ?) is shorter than the corresponding bond in the parent compound [Fe2(CO)7(bpy)]. The substitution of CO by a phosphine ligand has hardly any influence on the Fe-Fe bond length, which is 2.6048 (14) ? in this complex and 2.611 ? in [Fe2(CO)7(bpy)]. The [Fe2(CO)6(R-PyCa)] complexes do not show release of CO but instead show a change of coordination of the R-PyCa ligand from σ-N, μ-N′, η2-CN′ (6e) into σ,σ-N,N′ (4e) upon irradiation of a 133 K solution in 2-MeTHF at 488 nm. When the temperature of the solution with the photoproduct is raised to 173 K in the presence of free CO, [Fe2(CO)7(R-PyCa)] complexes are formed, which have the same structure as [Fe2(CO)7(L)] (L = bpy, phen) and are stable up to 260 K. The [Fe2(CO)6(R-DAB)] complexes show a similar change in coordination of the DAB ligand, which is however accompanied here by release of CO.
