[5,10,15,20-Tetra-kis(4-meth-oxy-phen-yl)porphyrinato]zinc di-chloro-methane disolvate.

In the title compound, [Zn(C48H36N4O4)]·2CH2Cl2, the Zn(II) ion lies on an inversion center and is coordinated in an almost ideal square-planar geometry. The asymmetric unit also contains one di-chloro-methane solvent mol-ecule. The unique meth-oxy-substituted benzene rings form dihedral angles of 59.

[5,10,15,20-Tetra-kis(4-tol-yl)porphyrin]zinc(II) dichloro-methane solvate.

In the title complex, [Zn(C(48)H(36)N(4))]·CH(2)Cl(2), the Zn(II) atom lies on an inversion center and the dichloro-methane solvent mol-ecule is disordered around an inversion center. The tolyl substituents are twisted compared to the central aromatic ring system of the porphyrin, similar to what is seen in previously published structures of this molecule [Dastidar & Goldberg (1996 ▶). Acta Cryst.

Tetrapyrrole singlet excited state quenching by carotenoids in an artificial photosynthetic antenna.

Two artificial photosynthetic antenna models consisting of a Si phthalocyanine (Pc) bearing two axially attached carotenoid moieties having either 9 or 10 conjugated double bonds are used to illustrate some of the function of carotenoids in photosynthetic membranes. Both models studied in toluene, methyltetrahydrofuran, and benzonitrile exhibited charge separated states of the type C*+-Pc*- confirming that the quenching of the Pc S1 state is due to photoinduced electron transfer. In hexane, the Pc S1 state of the 10 double bond carotenoid-Pc model was slightly quenched but the C*+-Pc*- transient was not spectroscopically detected.

Artificial photosynthetic reaction centers: mimicking sequential electron and triplet-energy transfer.

An artificial photosynthetic reaction center consisting of a carotenoid (C), a dimesitylporphyrin (P), and a bis(heptafluoropropyl)porphyrin (P(F)), C-P-P(F) , and the related triad in which the central porphyrin has been metalated to give C-P(Zn)-P(F) have been synthesized and characterized by transient spectroscopy. These triads are models for amphipathic triads having a carboxylate group attached to the P(F) moiety; they are designed to carry out redox processes across lipid bilayers. Triad C-P-P(F) undergoes rapid singlet-singlet energy transfer between the porphyrin moieties, so that their excited states are in equilibrium.