Five- and six-coordinate high-spin iron(III) porphyrin complexes with teflate (OTeF5-) ligands

Six-Coordinate Thallium(III) Porphyrin Triflate: Synthesis, Physiochemical Characteristics, and X-ray Crystal Structure of (Trifluoromethanesulfonato)(tetrahydrofuran)(meso-tetraphenylporphyrinato)thallium(III) Tetrahydrofuran Solvate, [Tl(tpp)(OSO2CF3)(THF)·THF]

“…This longer Tl···O(4) contact is described as the effective coordination (or as “semicoordinated”). , The short Tl(1)−O(1) distance and the displacement of the thallium atom toward the triflate are consistent with a much stronger metal ligand bond to the triflate anion than to the THF molecule. This type of asymmetry in bond lengths was also observed for Fe(tpp)(OTeF 5 )(THF) with Fe−O(OTeF 5 ) = 1.967 Å and Fe−O(THF) = 2.334 Å . In compound 1 , the interaction of CF 3 SO 3 - with thallium is purely unidentate, the second (or the third) triflate oxygen i.e.…”

Horizontal and Vertical Push Effects in Saddled Zinc Porphyrin Complexes: Implications for Heme Distortion

“…Also note that because of the unique five-coordinate nature of zinc­(II) in porphyrins, it is suitable to independently examine the push role of imidazole or pull role of O 2 ; however, it is unsuitable to examine the synergistic effect originating from these two ligands in the same molecule. This synergy should be present in heme because of the flexible interconversion of iron species between the five- and six-coordinate forms …”

“…This synergy should be present in heme because of the flexible interconversion of iron species between the fiveand sixcoordinate forms. 49 The single-point energy comparison also provides important information about the abnormal energy level alternation of the complexes (Figure 4a). On the one hand, unlike the orbital splitting between the antibonding d orbitals (d γ ) and bonding ones (d ε ) described by the Jahn−Teller effect, 50 the relative E d between zinc d γ and d ε is almost unchanged during the push/ pull processes induced by the geometric and/or electronic effects, but almost either rises or falls simultaneously, which means that the five d orbitals jointly participate in a redistribution of the accumulated charge.…”

A “Magnetochemical” Series. Ligand Field Strengths of Weakly Binding Anions Deduced from S = 3/2, 5/2 Spin State Mixing in Iron(III) Porphyrins

“…OEP is only a marginally stronger field macrocycle than TPP. Nevertheless, the 1 H NMR spectrum of Fe(OTeF 5 )(OEP) hints that X = OTeF 5 - is shifted into the admixed regime . The effect of phthalocyanine is more dramatic.…”

“…Since stronger field axial ligands such as halides, alkoxides, azide, thiocyanate, η 2 -nitrate, thiolates, carboxylates, sulfonates, μ-oxide, sulfate, bisulfate, and teflate (OTeF 5 - ) all form high-spin complexes in the FeX(TPP) series, they can be grouped at the high-field end of the series but not ranked. However, while it is not possible to form a more extended magnetochemical series from data on tetraphenylporphyrin complexes, the series can be extended to other sequences by changing the macrocycle.…”