Catalytic decarbonylation of aldehydes using iron(II) porphyrin complexes, and the crystal structure of (5,10,15,20-tetraphenylporphinato)bis(tri-n-butylphosphine)iron(II)

• Published in: Canadian journal of chemistry 1988-08, Vol.66 (8), p.2072-2078
• Main Authors: Belani, Ramesh M, James, Brian R, Dolphin, David, Rettig, Steven J
• Format: Article
• Language: English
• Subjects: Chemistry; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Inorganic compounds; Kinetics and mechanisms; Metal complexes; Organic chemistry; Physics; Reactivity and mechanisms; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v88-332

The complex (5, 10, 15, 20-tetraphenylporphinato)bis(tri-n-butylphosphine)iron(II), 1 , has been isolated in a triclinic crystal form, a = 12.499(3), b = 12.528(2), c = 12.039(2) Å, α = 116.39(1), β = 109.79(1), γ = 98.13(1)°, Z = 1, space group . The structure was solved by conventional heavy atom methods and was refined by full-matrix least-squares procedures to R = 0.060 and R w  = 0.070 for 3551 reflections with I ≥ 3σ(I). The molecule, which has crystallographic , symmetry, displays a relatively undistorted pseudo-octahedral coordination geometry with FeP = 2.346( 1 ) and FeN = 1.998(3) and 1.993(3) Å. In CH 2 Cl 2 solution, 1 reacts with CO and aldehydes to generate the carbonyl(phosphine) derivative, and decarbonylation of phenylacetaldehyde to toluene becomes catalytic under an Ar stream. The aldehyde decarbonylations involve radical pathways via carbonyl loss from . The hydrogen abstraction/initiation reaction probably utilizes trace O 2 (and possibly trace (water); speculative mechanisms are discussed.