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RESEARCH PRODUCT

Electrochemical, Spectroelectrochemical, and Structural Studies of Mono- and Diphosphorylated Zinc Porphyrins and Their Self-Assemblies

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International audience; Three series of porphyrins containing a Zn(II) central metal ion and zero, one or two phosphoryl groups at the meso-positions of the macrocycle were characterized as to their electrochemical, spectroscopic and structural properties in non-aqueous media. The investigated compounds are represented as 5,15-bis(4'-R-phenyl)porphyrinatozinc, 10-(diethoxyphosphoryl)-5,15-bis(4'-R-phenyl)porphyrinatozinc and 5,15-bis(diethoxyphosphoryl)-10,20-bis(4'-R-phenyl)porphyrinatozinc, where R = OMe, Me, H or CN. Linear-free energy relationships are observed between the measured redox potentials at room temperature and the electronic nature of the substituents at the 5 and 15 meso-phenyl groups of the macrocycle. The mono-and bis-phosphoryl derivatives with two p-CNPh substituents provide electrochemical evidence for aggregation at low temperature, a greater degree of aggregation being observed in the case of 5,15-bis(diethoxyphosphoryl)-10,20-bis(4'-CN-phenyl)porphyrinatozinc(II). This compound was characterized in further detail by variable temperature 1 H and 31 P{1H} NMR spectroscopy in solution combined with single crystal X-ray analysis in the solid state. The data obtained from these measurements indicating that this porphyrin has a dimeric structure in CDCl3 at 223-323 K but forms a 2D polymeric network when it is crystalized from a CHCl3/MeOH mixture.