Formation of dodecaphenylporphodimethene via facile protonation of saddle-distorted dodecaphenylporphyrin

Abstract

A saddle-distorted dodecaphenylporphyrin undergoes protonation followed by two-electron reduction by SnCl(2) to give a roof-shaped dodecaphenylporphodimethene which exhibits reversible one-electron reduction and oxidation behaviour in benzonitrile to allow us to observe an ESR spectrum of pi-cation radical in the course of electrochemical oxidation.

Synthesis, Electrochemistry, and Reversible Interconversion among Perhalogenated Hydroxyphenyl Ni(II) Porphyrins, Porphodimethenes, and Porpho-5,15-bis-paraquinone Methide

“…This similarity between potentials for the one-electron reduction of NiTPPCl 8 at E 1/2 = −0.82 V and the proposed electrogenerated porphodimethene product generated from 2 ( E 1/2 = −0.88 V) is not unexpected on the basis of data in the literature showing almost identical reduction potentials for free-base do­deca­phenyl­porphyrin ( E 1/2 = −1.28 V) and its do­deca­phenyl­porpho­dimethene product ( E 1/2 = −1.30 V) in CH 2 Cl 2 or between the first one-electron reduction of NiOEP in CH 2 Cl 2 ( E 1/2 = −1.46 V) and the meso -dimethyl Ni­(II) porphodimethene product in the same solvent ( E 1/2 = −1.52 V) …”

“…The first reduction of 2 and 3 in CH 2 Cl 2 with increasing H + concentration was further investigated by plotting the measured peak potential in the CH 2 Cl 2 /TFA mixtures as a function of increasing acid concentration in solution, which varied from 10 −3 to 10 −1 M. These plots are shown in Figure 9, where E p vs log[H + ] is linear with a slope close to the theoretical Nernstian value of −60 mV expected for a rate-determining step involving the addition of one electron and one proton or two electrons and two protons. 30 This result and the known chemistry which occurs during the reduction of porphyrins in acidic nonaqueous media 31 strongly suggest an overall two-electron, two-proton transfer and the formation of porphodimethenes as probable products of the electron-transfer reactions.…”

Construction of SnIV Porphyrin/Trinuclear Ruthenium Cluster Dyads Linked by Pyridine Carboxylates: Photoinduced Electron Transfer in the Marcus Inverted Region

“…Crystallographic data for 1 – 4 are also summarized in Table 4. CCDC‐702272 ( 1 ⋅CHCl 3 ),42 752023 ( 2⋅ CH 2 Cl 2 ), 752024 ( 3 ), and 752025 ( 4 ) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/cgi-bin/catreq.cgi.…”

Nonplanar porphyrins: synthesis, properties, and unique functionalities

“…Dodecaarylporphyrins, 81 such as those reported by Kojima and co-workers, 189 result in saddle-shaped porphyrins in only some cases; these more conformationally flexible examples adopt saddle, ruffle or wave conformations, dependent on the intermolecular packing arrangement of the crystal structure. 134,166 b Structures of dodecaarylporphyrins have been reported with M = 2H, 81,190 3H, 191 4H, 189 b V IV , 189 a Mn III , 192 Fe III , 193 Co II , 81 Ni II , 148,190 Cu II , 81 Zn II , 194 Mo V , 195 Sn II , 142 Sn IV , 196 Rh, 197 Ru 198 and Os. 198…”