Ikezaki, Akira; Nakamura, Mikio published the artcile< Models for Cytochromes c': Spin States of Mono(imidazole)-Ligated (meso-Tetramesitylporphyrinato)iron(III) Complexes as Studied by UV-Vis, 13C NMR, 1H NMR, and EPR Spectroscopy>, HPLC of Formula: 36947-69-0, the main research area is cytochrome c model imidazole iron porphyrin complex; spin state imidazole iron porphyrin complex; ESR imidazole iron porphyrinato; solvent effect spin state imidazole iron porphinato; UV visible imidazole iron porphyrin complex; NMR chem shift imidazole iron porphyrin complex.
A number of mono(imidazole)-ligated complexes of (meso-tetramesitylporphyrinato)iron(III) perchlorate, [Fe(TMP)L]ClO4, were prepared, and their spin states were examined by 1H NMR, 13C NMR, and EPR spectroscopy as well as solution magnetic moments. All the complexes examined showed a quantum mech. spin admixed state of high and intermediate-spin (S = 5/2 and 3/2) states, though the contribution of the S = 3/2 state varies depending on the nature of axial ligands. While the complex with extremely bulky 2-tert-butylimidazole (2-tBuIm) has exhibited an essentially pure S = 5/2 state, the complex with electron-deficient 4,5-dichloroimidazole (4,5-Cl2Im) adopts an S = 3/2 state with 30% of the S = 5/2 spin admixture From the 1H and 13C NMR results, the S = 3/2 contribution at ambient temperature increases according to the following order: 2-tBuIm < 2-(1-EtPr)Im < 2-MeIm ≤ 2-EtIm ≤ 2-iPrIm < 4,5-Cl2Im. The effective magnetic moments determined by the Evans method in CH2Cl2 solution are 5.9 and 5.0 μB at 25° for [Fe(TMP)(2-tBuIm)]ClO4 and [Fe(TMP)(2-MeIm)]ClO4, resp., which further verify the order given above. Comparison of the NMR and EPR data revealed that the S = 3/2 contribution changes sensitively by the temperature; the S = 3/2 contribution decreases as the temperature is lowered for all the mono(imidazole) complexes examined The solvent polarity also affects the spin state; polar solvents such as MeOH and MeCN increase the S = 3/2 contribution while nonpolar solvents such as benzene decrease it. These results are explained in terms of the structurally flexible nature of the mono(imidazole) complexes; structural parameters such as the Fe(III)-Naxial bond length, displacement of the Fe from the N4 core, tilting of the Fe(III)-Naxial bond to the heme normal, orientation of the coordinated imidazole ligand, etc., could be altered by the nature of the axial ligands as well as by the solvent polarity and temperature Some mysteries on the spin states of cytochromes c' isolated from various bacterial sources are possibly explained in terms of the flexible nature of the mono(imidazole)-ligated structure. Inorganic Chemistry published new progress about ESR (electron spin resonance). 36947-69-0 belongs to class imidazoles-derivatives, and the molecular formula is C7H12N2, HPLC of Formula: 36947-69-0.
Referemce:
Imidazole – Wikipedia,
Imidazole | C3H4N2 – PubChem