Methylviologen-pendant iron porphyrins as models of a reduction enzyme: six-electron reduction of nitrobenzene to anilineElectronic supplementary information (ESI) available: time-courses of reduction, UV-VIS spectral changes, cyclic voltammograms, EPR spectra, conversion and yield percentages for the reduction of p-nitroanisole. See http://www.rsc.org/suppdata/dt/b2/b211125j/

Abstract

Methylviologen-pendant iron porphyrins, in which methylviologen was introduced to the meso-phenyl group through an amido-bridge at either the p-or m-position, were newly synthesized, in expectation that these methylviologenpendant iron porphyrins would be good functional models of a multi-electron reductase such as nitrite reductase since the methylviologen-pendant can play the role of an electron-trapping and storage unit like the iron-sulfur cluster of the nitrite reductase. These iron porphyrins were successfully applied to the six-electron reduction of nitrobenzene to aniline, which is a model reaction of nitrite reduction to ammonia catalyzed by nitrite reductase. Both p-and m-methylviologen-pendant iron porphyrins give somewhat larger yields of aniline in the reduction of nitrobenzene and much larger yields of p-methoxyaniline in the reduction of p-nitroanisole than does normal iron tetraphenylporphyrin. Though normal iron tetraphenylporphyrin can not catalyze well the reduction of p-nitroanisole in the presence of the dioxygen molecule, these methylviologen-pendant iron porphyrins can catalyze well the reduction of p-nitroanisole and give a considerably larger yield of p-methoxyaniline even in the presence of the dioxygen molecule. These methylviologen-pendant iron porphyrins give a much larger yield of aniline in the reduction of nitrosobenzene and somewhat larger yield of aniline in the reduction of phenylhydroxylamine than does iron tetraphenylporphyrin. m-Methylviologen-pendant iron porphyrin exhibits higher catalytic activity than does the p-pendant one. The role of methylviologen moiety is discussed, based on cyclic voltammograms and UV-VIS spectra of these iron porphyrins.

A Sn(iv) porphyrin with mitochondria targeting properties for enhanced photodynamic activity against MCF-7 cells

“…The starting compounds, 5-[4-(3-bromoethylcarboxyamidyl)phenyl]-10,15,20-triphenylporphyrin ( P1 ), 5-[4-(triphenylphosphonium) ethylcarboxyamidyl)phenyl]-10,15,20-triphenylporphyrin ( P2 ) were prepared according to previous reports (Scheme 1). 37 SnP and SnPH were synthesized by a slightly modified procedure reported previously (Scheme 1). 18 SnCl 2 (47.4 mg, 0.25 mmol) was added to 2 ml of 0.025 mmol solutions of the respective porphyrins in dry DMF [ P1 (19 mg) and P2 (25.6 mg)].…”

Accessible, Direct Photochemical Route for the Amine-Free Synthesis of Azoxybenzene and Functional Azoxy Derivatives via Nitroarene Homocoupling

“…For example, the catalytic reduction of a nitrocompound with H2 gas is often conducted at elevated temperatures (100-150 °C) and pressures (10-50 bar), which results in low product selectivity due to the nonselective hydrogenation of other functional groups. 43 Catalysis has played a crucial role in developing all areas of modern synthetic chemistry. 42 Approximately 85% of the world's aniline is created using catalytic processes.…”

Accessible, Direct Photochemical Route for the Amine-Free Synthesis of Azoxybenzene and Functional Azoxy Derivatives via Nitroarene Homocoupling

“…For example, the catalytic reduction of a nitrocompound with H2 gas is often conducted at elevated temperatures (100-150 °C) and pressures (10-50 bar), which results in low product selectivity due to the nonselective hydrogenation of other functional groups. 43 Catalysis has played a crucial role in developing all areas of modern synthetic chemistry. 42 Approximately 85% of the world's aniline is created using catalytic processes.…”