RESUMO
Iron(i) species are debated as key intermediates during the C-halide activation step in Kumuda type C-C cross-coupling catalysis. However, there is only limited knowledge on the reactivity of isolable iron(i) complexes towards organohalides. Using the known two-coordinate iron(i) complex K{18c6}[FeI(N(SiMe3)2)2] we disclose its proficiency to rapidly cleave different types of carbon halide bonds including even C-F bonds. Mechanistic studies indicate stepwise one-electron processes with the involvement of organoradicals.
RESUMO
Two known and two new ortho-phenyl phosphonium-sulfonate compounds have been synthesized and analyzed in solution and in the solid state. When the phosphonium moiety bears alkyl substituents, two rotamers are in equilibrium in solution. These two rotamers have been entirely characterized and are shown to differ by the spatial arrangement of the phosphonium proton relative to the sulfonate moiety. The phosphonium proton chemical shift and the 1JPH coupling constant are characteristic values for each rotamer. The kinetic and thermodynamic constants have been determined by means of NMR and DFT studies.
RESUMO
The coordination ability of the bis(2-picolyl)phenylphosphine (NPN) compound has been probed toward the iron precursor [Fe{N(SiMe3)2}2]. By a careful control of the experimental conditions we were able to isolate and characterize three complexes displaying different coordination modes of the NPN ligand as revealed in particular by X-ray diffraction, and multinuclear solution and solid state NMR analyses. It is shown that NPN can be used as a proton-responsive ligand with enough flexibility to allow the formation of the dinuclear complex [Fe{P(CH2(C5H4N))(CH(C5H4N))}(N(SiMe3)2)]2 with two NPN ligands spanning the two metal centres.