A new general one-pot method for the synthesis of various metalloporphyrins has been developed from pyrrole and substituted aldehydes using transition metal salts. This method allows higher working concentrations than those previously reported. Along with the reported metalloporphyrins, some new metalloporphyrins were synthesized in good yield.
Catalytic activity of carbon nanotube supported iron(III) and manganese(III) porphyrins in oxidation of olefins with tert-butyl hydroperoxide: Higher activity of the iron(III) porphyrin
作者:Saeed Rayati、Parisa Jafarzadeh、Saeed Zakavi
DOI:10.1016/j.inoche.2012.11.017
日期:2013.3
manganese and iron porphyrin. In comparison of the two metalloporphyrins, catalyticactivity of the manganese porphyrin is more sensitive to the type of solvent than the iron one. In spite of the crucial role of imidazole (ImH) on catalytic performance of the manganese porphyrin, the presence of ImH has a negative effect on the activity of the iron porphyrin. The nano-tube supported iron porphyrin may
Differential Sensing of Protein Influences by NO and CO Vibrations in Heme Adducts
作者:Mohammed Ibrahim、Changliang Xu、Thomas G. Spiro
DOI:10.1021/ja064859d
日期:2006.12.1
Heme proteins bind the gaseous ligands XO (X = C, N, O) via backbonding from Fe d(pi) electrons. Backbonding is modulated by distal interactions of the bound ligand with the surrounding protein and by variations in the strength of the trans proximal ligand. Vibrational modes associated with FeX and XO bond stretching coordinates report on these interactions, but the interpretive framework developed for CO adducts, involving anticorrelations of nu FeC and nu CO, has seemed not to apply to NO adducts. We have now obtained an excellent anticorrelation of nu FeN and nu NO, via resonance Raman spectroscopy on (N-methylimidazole)Fe(II)TPP-Y(NO), where TPP-Y is tetraphenylporphine with electron-donating or -withdrawing substituents, Y, that modulate the backbonding; the problem of laser-induced dissociation of the axial base was circumvented by using frozen solutions. New data are also reported for CO adducts. The anticorrelations are supported by DFT calculations of structures and spectra. When protein data are examined, the NO adducts show large deviations from the modeled anticorrelation when there are distal H-bonds or positive charges. These deviations are proposed to result from closing of the FeNO angle due to a shift in the valence isomer equilibrium toward the Fe(III)(NO-) form, an effect that is absent in CO adducts. The differing vibrational patterns of CO and NO adducts provide complementary information with respect to protein interactions, which may help to elucidate the mechanisms of ligand discrimination and signaling in heme sensor proteins.
A Green Process for Oxidation of <i>p</i>-Nitrotoluene Catalyzed by Metalloporphyrins under Mild Conditions
作者:Lanzhi Wang、Yuanbin She、Rugang Zhong、Hongbing Ji、Yanhui Zhang、Xufeng Song
DOI:10.1021/op060056z
日期:2006.7.1
A novel synthetic technology of p-nitrobenzoic acid has been investigated with dioxygen by using metalloporphyrins RTPP-(MCl)-Cl-III (M = Fe, Co, Mn) as biomimetic catalysts. Oxidation of p-nitrotoluene to p-nitrobenzoic acid under 2.0 MPa of O-2 in the presence of a microamount of metalloporphyrins (RTPP-(MCl)-Cl-III) at 55 degrees C was achieved with the highest ( up to 90.4%) yield. Further research results show that the catalytic activities were relative to the nature of the substituted groups and the central metal ions of metalloporphyrins. For the metalloporphyrins with the same center metal ions, the greater the electron-withdrawing degree of groups in the porphyrin ring, the higher the catalytic activities of the metalloporphyrins. The catalytic activities for metalloporphyrins with different center metal ions followed the order RTPPMn Cl-III > RTPP (FeCl)-Cl-III > RTPP (CoCl)-Cl-III.