Novel Iron Porphyrin−Alkanethiolate Complex with Intramolecular NH···S Hydrogen Bond:  Synthesis, Spectroscopy, and Reactivity

Direct Observation of a Novel Perturbed Oxyferrous Catalytic Intermediate during Reduced Putidaredoxin-initiated Turnover of Cytochrome P-450-CAM

“…The role of H-bonding to the proximal Cys by peptide amide N-H groups has been examined by Ogliaro et al (42) using density functional theory; these studies concluded that H-bonding strengthens the iron-sulfur bond while enhancing the porphyrin -cation radical character of compound I at the expense of a diminished thiyl radical component. Experimental investigations have also revealed a link between H-bonding to the thiolate sulfur in P-450 and mono-oxygenase activity (23,24,43).…”

Homogeneous and Heterogeneous Free-Based Porphyrins Incorporated to Silica Gel as Fluorescent Materials and Visible Light Catalysts Mimic Monooxygenases

“…The porphyrins have become an indispensable component in the evolution of living organisms, due to many types of chemical reactions, characteristic of this group of compounds, such as coordination, polymerization, aggregation, oxidation and reduction, catalysis, sorption and photochemical changes. Several synthetic models based on porphyrins for heme oxidases have been developed in order to understand principles of the complex mechanism of dioxygen activation and oxygen atom transfer processes, and to obtain valuable information on the nature and reactivity of intermediates produced in the catalytic cycles of metalloenzymes in living organisms (Hessenauer-Ilicheva at al., 2007;Dallacosta et al, 2007;Nam, 2007;Suzuki et al, 1999). The extensive investigation of metalloporphyrins catalyzed oxidation reaction has concentrated on using iron (III) and manganese (III) and the role of pyridine and imidazole ligands.…”

“…The monooxygenation by metalloporphyrins with these oxidants requires the presence of pyridine or 1-methylimidazol, 4-butylpyridine, imidazole, or ammonium acetate, which were shown to act both as axial ligands and cocatalyst used to promote the desired heterolytic cleavage of peroxide and also to stabilize the active species Mn(V)=O formed in the oxidation cycle (Meunier, 1992;Gonsalves et al, 1996;Maraval et al, 2002;Susana et al, 2003;Cantonetti et al, 2004). These agents substantially increased the rate of the regio-and stereoselectivity reaction, and their role resembles somewhat the action of the strongly nucleophilic thiolate axial ligand in cyt-P450, which is crucial for heterolytic cleavage of the O-O bond of hydroperoxo intermediate by donating the electron density to this bond (Suzuki at al., 1999;Watanabe, 2000). Cytochromes P450 mimics using O 2 itself as an oxygen atom donor has also been developed.…”

Electronic features and hydrogen bonding capacity of the sulfur acceptor in thioureido-based compounds. Part 2. Further insight by theoretical charge density study

“…Although a number of studies indicate the significance of DAHÁ Á ÁS interactions for structure and function of biological systems [1][2][3][4][5][6][7][8][9][10][11] as well as inorganic materials [12][13][14][15][16] the acceptor abilities of the S atom are not sufficiently explored. In general, due to a low electronegativity, the sulfur is rarely considered as a relevant hydrogen bonding acceptor.…”