Zinc porphyrins synthesis

An interesting variation on this theme has been reported by Lehn and coworkers. In 1986, they reported the synthesis of macrocycle 33, which consists of a zinc porphyrin bearing two linked cyclic binding subunits [87]. It was later found that addition of silver triflate to a solution of 33 in methanol resulted in the incorporation of a silver ion in each of the binding subunits [88], Thus, the complex may be represented as Ag+-P-Ag+. The porphyrin fluorescence of the silver complex was quenched, and transient absorption studies demonstrated that the porphyrin singlet state was quenched with a rate constant of 5.0 x 109 s 1 to yield a charge separated state Ag°-P+-Ag+. Some quenching of the porphyrin triplet... 

In 2007, a photoresponsive molecular tweezer, zinc porphyrin-dithienylethene-zinc porphyrin (ZnP-DTE-ZnP) triad was reported by Park and Shin (Scheme 4) [32], The main synthesis procedure was the Wittig reaction between 5-(4-bromo-methylphenyl)-10,15,20-tris (4-methylphenyl)-porphyrin and l,2-di(2-methyl-4-formyl-3-thiophenyl) perfluorocyclopentene. 

In 2005, Rowan, Nolte, and coworkers described an efficient and templated synthesis of porphyrin boxes using DCC and reversible metathesis reaction [54]. Cyclic tetramers were successfully prepared in good yields (62%) from an olefin-functionalized zinc porphyrin in the presence of first generation Grubb s catalyst and upon addition of a tetrapyridyl porphyrin (TPyP) serving as a template. While a mixture of linear and cyclic oligomers was obtained in the absence of template, addition of TPyP resulted in a reorganization of the DCL to favor the formation of the desired tetrameric box (Fig. 7a). 

The photophysics and photochemistry of gaseous PuFe have been ex-amined. Studies involving zinc porphyrins have been reported and include photo-oxidations in aqueous solution, photoreductions of Zn-TPP with hydrazines, and the role of Zn-TPPSa/ethyl viologen in photoredox processes. The mechanism of the photo-oxidation of water to oxygen with silver chloride has been discussed, and the synthesis of bis(chlorosilyl)-mercury compounds described. Colloidal CdSe has been shown to sensitize the photoreduction of O2 and of methyl viologen by cysteine. ... 

Onitsuka and Takahashi reported the synthesis and characterization of zinc porphyrin core dendrimers with platinum acetylide based dendrons... 

Representative examples of dendrimers with metal-containing cores include the materials 8.1-8.6, which were reported in the mid- to late 1990s. For example, first- (8.1), second- (8.2), third- (8.3), and fourth- (8.4) generation zinc porphyrin dendrimers (M = Zn) have been prepared by a convergent synthesis approach [18, 19]. Although the electrochemical and photophysical nature of the metalloporphyr-in core was found to be preserved in the resultant materials, the rate of interfacial electron transfer was found to be reduced due to the separation of the electroactive centers from the electrode surface. Second- (8.5) and third-generation (8.6)... 

Yamamoto, T., et al. 2000. Synthesis and chemical properties of pi-conjugated zinc porphyrin polymers with arylene and aryleneethynylene groups between zinc porphyrin units. Macromolecules 33 5988. 

Inspired by previous rotaxane assemblies, Ito and Tanaka have reported the synthesis and the properties of triad 130 incorporating two zinc porphyrins and a mechanically attached Ceo electron acceptor. The behavior of the assembly depicted in Figure 13.70 is impressive in terms of lifetime of the CS state. The charge separation quantum yield is efficient (95%), and excitation of the zinc porphyrins leads to an eT process from their first singlet excited state of ZnP to... 

Based on this concept, Krebs and coworkers [197] reported a synthesis of a light-harvesting material that consists of three structural domains. Two of them are conjugated homopolymers that are linked with a zinc porphyrin ... 

Yamamoto and co-workers have studied the synthesis of zinc porphyrin polymers (57) by polycondensation of 56 using Ni and Pd catalysts (128) (eq. 16). Functionalizing the zinc porphyrins and aromatic spacers with alkyl groups enhanced the solubility of these polymers. In addition, various aromatic spacers were studied in order to decrease the steric crowding surroimding the porphyrins. The molecular weights of these polymers were between 4600 and 37,900 (PDI = 1.3-1.8), and thin films of these polymers were electrochemically active and exhibited electrochromism. 

Lee C-W, Lu H-P, Lan C-M et al (2009) Novel zinc porphyrin sensitizers for dye-sensitized solar cells synthesis and spectral, electrochemical, and photovoltaic properties. Chem Eur J 15(6) 1403-1412... 

Seo KD, Lee MJ, Song HM et al (2012) Novel D-a-A system based on zinc porphyrin dyes for dye-sensitized solar cells synthesis, electrochemical, and photovoltaic properties. Dyes Pigm 94(1) 143-149... 

Sandanayaka, A. S. D. et al. Synthesis and photoindnced electron transfer processes of rotaxanes bearing [60]fullerene and zinc porphyrin Effects of interlocked structure and length of axle with porphyrins. J. 

In related work, Harriman et al. [77] reported the synthesis of a cytosine derivative possessing an appended benzo-l,4-quinone moiety (14). Mixing in chloroform solution with the zinc porphyrin bearing a guanine residue resulted in the formation of a 1 1 complex due to formation of a 3-point hydrogen bond between the nucleic acid bases. The association constant was found to be 1290 M and fluorescence from the porphyrin was found... 

Takeuchi explored a very interesting system consisting of a monoboronic acid zinc porphyrin 243 and monoboronic acid pyridine unit 244." Self-assembly of the porphyrin and pyridine results in a diboronic acid . This system is particularly interesting since the synthesis of monoboronic acids is much easier than that of diboronic acids. Modification of each constituent monoboronic acid is therefore much easier than that required in the direct... 

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