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The spin states of the iron(III) complexes with a highly ruffled porphyrin ring, [Fe(TEtPrP)X] where X = F-, Cl-, Br-, I-, and ClO4(-), have been examined by 1H NMR, 13C NMR, EPR, and Mössbauer spectroscopy. While the F-, Cl-, and Br- complexes adopt a high-spin (S = 5/2) state, the I- complex exhibits an admixed intermediate-spin (S = 5/2, 3/2) state in… (More)
Six-coordinate low-spin iron(III) porphyrinates adopt either common (d(xy))(2)(d(xz),d(yz))(3) or less common (d(xz),d(yz))(4)(d(xy))(1) ground state. In this review article, three major factors that affect the electronic ground state have been examined. They are (i) nature of the axial ligand, (ii) electronic effect of peripheral substituents, and (iii)… (More)
1H NMR, (13)C NMR, and EPR spectra of six-coordinate ferric porphyrin complexes [Fe(Por)L2]ClO4 with different porphyrin structures are presented, where porphyrins (Por) are planar 5,10,15,20-tetraphenylporphyrin (TPP), ruffled 5,10,15,20-tetraisopropylporphyrin (TiPrP), and saddled 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin (OETPP), and… (More)
Isocyanide-bound model hemes always adopt the (dxz, dyz)4(dxy)1 ground state, however, we have found that the replacement of porphyrin by diazaporphyrin leads to the formation of an unprecedented low-spin bis(tert-butylisocyanide) complex with the (dxy)2(dxz, dyz)3 ground state.
Bis(pyridine)[meso-tetrakis(heptafluoropropyl)porphyrinato]iron(III), [Fe(THFPrP)Py(2)](+), was reported to be the low-spin complex that adopts the purest (d(xz), d(yz))(4)(d(xy))(1) ground state where the energy gap between the iron d(xy) and d(π)(d(xz), d(yz)) orbitals is larger than the corresponding energy gaps of any other complexes reported previously… (More)
The electronic structures of six-coordinate iron(III) octaethylmonoazaporphyrins, [Fe(MAzP)L 2] (+/-) ( 1), have been examined by means of (1)H NMR and EPR spectroscopy to reveal the effect of meso-nitrogen in the porphyrin ring. The complexes carrying axial ligands with strong field strengths such as 1-MeIm, DMAP, CN (-), and (t)BuNC adopt the low-spin… (More)
The electronic states of a series of saddle-shaped porphyrin complexes [Fe(OMTPP)L(2)](+) and [Fe(TBTXP)L(2)](+) have been examined in solution by (1)H NMR, (13)C NMR, and EPR spectroscopy and by magnetic measurements. While [Fe(OMTPP)(DMAP)(2)](+) and [Fe(TBTXP)(DMAP)(2)](+) maintain the low-spin (S = (1)/(2)) state, [Fe(OMTPP)(THF)(2)](+) and… (More)
To determine the factors affecting the ground-state electron configuration of low-spin Fe(III) porphyrin complexes, we have examined the (1)H NMR, (13)C NMR, and EPR spectra of a series of low-spin bis-ligated Fe(III) porphyrin complexes [Fe(Por)L(2)](+/-), in which the positions of porphyrin substituents and the coordination ability of axial ligands are… (More)
The title complex, (diethyl 3,4,8,15,19,20-hexamethyl-21,22,23,24-tetraazopentacyclo[22.214.171.124(2,5).1(7,11).1(14,17)]tetracosa-1(20),2(22),3,5,7,9,11,13(24),14,16,18-undecaene-9,14-dicarboxylate-kappa4N)iodoiron(III) chloroform solvate, [Fe(C32H32N4O4)I].CHCl3, shows an almost planar arrangement of the corrphycene moiety with a slightly distorted trapezoid… (More)
A novel spin transition between S = 5/2 and S = 3/2 has been observed for the first time in five-coordinate, highly saddled iron(III) porphyrinates by EPR and SQUID measurements at extremely low temperatures.