Viologen-linked Porphyrins Research Articles

Photoinduced hydrogen production with the system containing water-soluble viologen-linked porphyrins and hydrogenase

Water-soluble viologen-linked cationic porphyrins (ZnP(C n V) 4, n=3–6) and anionic porphyrins (TPPSC n V, n=3–6) were synthesized and their photochemical properties were characterized. The quenching processes of the photoexcited state of porphyrin moiety by the bonded viologen were measured by fluorescence lifetime and laser flash photolysis, and photoinduced hydrogen evolution with ZnP(C n V) 4 or TPPSC n V and hydrogenase from Desulfovibrio vulgaris (Miyazaki) was performed under steady state irradiation.

Preparation and characterization of viologen-linked zinc porphyrins

Preparation and characterization of viologen-linked zinc porphyrins

1H NMR Conformational Study of Viologen-Linked Porphyrins (p-FCnV)

Abstract Conformation of viologen-linked porphyrins (p-PCnV, n=4–7), which are capable of intramolecular electron transfer, was studied by 1H NMR in order to gain insight into the relative geometry of the donor and acceptor during the electron transfer process. The orientation of the viologen with respect to the porphyrin was interpreted in terms of the rate of the intramolecular electron transfer between the two π-systems.

Photoinduced electron transfer in viologen-linked porphyrins ( m-PC nV)

Compounds containing a viologen linked to a porphyrin via a number ( n = 3 – 6) of methylene groups were synthesized. Photoinduced long-range electron transfer between the porphyrin and the viologen is observed. The photoexcited singlet state of the porphyrin is quenched by the viologen in the viologen-linked porphyrins. The fluorescence decay profiles of the viologen-linked porphyrins consist of the sum of two first-order decays with short and long lifetimes. The short lifetime arises from the direct quenching of the photoexcited singlet state of the porphyrin by the linked viologen. The intramolecular electron transfer process from the porphyrin to the viologen becomes less effective with increasing methylene chain length.

Photoinduced electron transfer in viologen-linked porphyrins (p-PC n V)

Compounds containing a viologen linked to a porphyrin via a number (n= 4–7) of methylene groups have been synthesized and photoinduced long-range electron transfer between porphyrin and viologen was observed. The photoexcited singlet state of the porphyrin was quenched by the bonded viologen in viologen-linked porphyrins. The fluorescence decay profiles of the viologen-linked porphyrins consist of a sum of two first-order decays with shorter and longer lifetimes. The shorter lifetime arises from the direct quenching of the photoexcited singlet state of the porphyrin by the linked viologen. The intramolecular electron transfer process from the porphyrin to the bonded viologen becomes less effective when the methylene chain length becomes longer.

Photoinduced Hydrogen Evolution with Viologen-Linked Porphyrins

Abstract Viologen-linked water-soluble porphyrins with different methylene chain lengths between porphyrin and viologen were synthesized. These compounds were applied to photoinduced hydrogen evolution in a system containing NADPH, viologen-linked porphyrin, and hydrogenase under steady-state irradiation.