Electrosynthesis and electrochemical properties of porphyrin dimers with pyridinium as bridging spacer

Abstract

Two porphyrin dimers (more precisely two isomers) with pyridinium as bridging spacer have been obtained by controlled potential electrolysis. This method is based on a nucleophilic substitution of a porphyrin substituted by a pyridyl group (namely 5,10,15-tritolyl-20-(4-pyridyl)porphyrin (H 2 T 3 P-4-Py) or 5,10,15-tritolyl-20-(3-pyridyl)porphyrin (H 2 T 3 P-3-Py)) on an electrogenerated radical cation of a zinc b-octaethylporphyrin (ZnOEP). The new compounds have been characterized by HR-MS, 1 H NMR, UV-vis and fluorescence spectroscopies. Difference of electrochemical behaviour of the pyridinium spacers between the two dimers has been also discussed.

Synthesis and characterization of Lindqvist-type polyoxometalate–porphyrin copolymers

“…The C-C bond of the dipyridyl bridge can be formed inside the same copolymer chain or between two copolymer chains (intra-or intermolecular reaction). Similar reactivity has been reported in the literature [38,39]. Upon limitation to iterative scans between 0.00 V and +1.60 V, we don't have such a reaction and are sure to avoid the formation of the dipyridyl linker.…”

Electrochemical and Spectroelectrochemical Properties of Free‐Base Pyridyl‐ and N‐Alkyl‐4‐Pyridylporphyrins in Nonaqueous Media

“…[40][41][42][43][44][45][46] In each case, there are two one-electron reductions, with the E 1/2 values being dependentu pon the number of meso-pyridyl groups and the specific electron-donating or electron-withdrawing substituents on the phenylg roups at the other meso positions of the macrocycle. The pyridyl groups are highly electron withdrawing and the E 1/2 values progressively shift in ap ositive direction with increasei nt he number of meso-pyridyl substituents, from one in the case of 1,w hich is reduced at E 1/2 = À1.13 and À1.52 Vi np yridine, to four in the case of 4,w hichi sr educed at À0.93 and À1.22 V, under the same solution conditions.…”

Porphyrins functionalized by quaternary pyridinium units

“…4-py afford dimers 13 and 14, respectively. The electrooxidation of a porphyrin proceeds via two one-electron steps E 1 and E 2 generating radical cation and dication [63].…”