97170-33-7Relevant academic research and scientific papers
Proton nuclear magnetic resonance studies of iron porphyrin complexes with a vinyl carbene inserted between iron and a pyrrole nitrogen
Balch, Alan L.,Cheng, Ru-Jen,La Mar, Gerd N.,Latos-Grazynski, Lechoslaw
, p. 2651 - 2656 (2008/10/08)
Proton NMR spectra have been obtained for the paramagnetic (S = 3/2) iron(III) complexes P[C=C(p-C6H4Cl)2]FeX (X = Cl, Br, I; P = porphyrin dianion from meso-tetraarylporphyrin, or protoporphyrin IX dimethyl ester). Functional group assignments have been made with use of selective deuterium and methyl labeling. More detailed assignments have been made on the basis of the temperature dependence of the spectra and analysis of the line widths, which are dominated by dipolar relaxation. The spectra are indicative of Cs symmetry for these complexes in solution. This result is in accord with the solid-state structure of these complexes but requires some oscillatory motion of one of the P-ClC6H4 groups. The dominant π-spin transfer to the pyrroles indicates that, of the alternate ground states (dxy)2(dxz)1(dyz) 1(dx2-y2)1 and (dxy)2(dxz)1(dyz) 1(dz2)1, the latter is present. The complexes exhibit axial magnetic anisotropy dominated by negative zero-field splitting. For the protoporphyrin IX derivative, the spectrum indicates that the four isomers resulting from carbene insertion into each of the four distinct Fe-N bonds are present.
