Tetrabenzoporphyrins

Blau and co-workers first reported observations of RSA in toluene solutions of Zn11 or Co11 meso-tetraphenylporphyrins with 80 ps pulses at 532 nm,147 and also proposed a theoretical mechanistic description for the cubic NLO properties of these complexes.148 RSA in Fe11 meso-tetraphenylporphyrin was later described by Fei et al.149 Other early 532 nm DFWM studies150-152 involve complexes of tetrabenzoporphyrins which were found in THF to display (3) values... 

Amongst the synthetic magnesium(II) complexes, a comparison of bis(pyridine)magnesium(II)-tetrabenzoporphyrin (26) with bis(pyridine)magnesium(II)-octamethyltetrabenzoporphyrin (10) in vitro (HeLa cells), and in vivo using liposomal delivery, showed that while (26) was more effective than (10) in cell kill, (10) had the greater tumor selectivity ([tumor]/[muscle] = 36.0 after 24 h). Zinc(II) tetrabenzoporphyrin also showed promising activity nickel(II) tetrabenzoporphyrin derivatives were inactive.117... 

L. Lee, N. H. Sabelli, and P. R. LeBreton, Theoretical characterization of phthalocyanine, tetraazaporphyrin, tetrabenzoporphyrin, and porphyrin electronic spectra, J. Phys. Chem, 86, 3926-3931 (1982). 

Metallooctaethylporphyrins Zinc tetra(benzo-15-crown-5)porphyrin See also Metallotetraphenylporphrins dimerization effects, 141,147 Zinc tetrabenzoporphyrin—See Metalloporphyrins Zinc tetraphenylporphyrin See also Metalloporphyrins See also... 

Platinum porphyrin complexes can be prepared by reaction with PtCl2(PhCN)2. Purification of the final complex is by medium pressure liquid chromatography on alumina. The strongly phosphorescent platinum(II) porphyrin complexes are efficient sensitizers for stilbene isomerization. The quantum yields for the cis to trans process are greater than unity because of a quantum chain process in which the metalloporphyrin serves both as an energy donor and an acceptor.1110 Picosecond laser spectroscopy has been used to obtain time-resolved excited-state spectra of platinum octaethylporphyrin complexes, and to probe the excited-state energy levels.1111 Tetrabenzoporphyrin complexes have been prepared for platinum in both the divalent and tetravalent oxidation states. The divalent complex shows strong phosphorescence at 745 nm.1112... 

On the preparative side, template reactions are again useful for example, the template condensation of phthalimide (or its potassium salt) with malonic acid or arylacetic acids in the presence of zinc or cadmium acetate has been shown to result in the formation of [ML] (H2L = tetrabenzoporphyrin or maso-tetraaryltetrabenzoporphyrin).1134,1135... 

The metallation of TPPH2 in D20 or H20 has been studied, and the rate difference (kn/kD = 2.3) shown to be due to differences in the concentration of OH and OD complexes, and not due to intrinsic differences in the reactivity of TPPH and TPPD.1149 The synthesis and properties of porphyrins bearing cationic or anionic substituents are areas of active interest, and zinc complexes of the ligands (172), tetrabenzoporphyrin and octamethylporphyrin have been studied.1150-1154... 

Several syntheses of tetrabenzoporphyrin complexes make use of similar template strategies to those used in phthalocyanine synthesis, so they will be discussed here. An isoindole has been found to undergo a very complex series of reactions promoted by a range of metal ions in refluxing 1,2,4-trichlorobenzene to produce tetrabenzoporphyrin complexes (Scheme 55).240 In contrast, an extremely simple synthesis of tetrabenzoporphyrin can be achieved from 2-acetylbenzoic acid, using zinc as templating metal (equation 44).241... 

New PHB materials are composed of Zn-tetrabenzoporphyrin—aromatic cyanide—poly (methyl methacrylate) (180) or of tetraphenylporphyrin derivatives dispersed in polymer matrices such as PMMA and polyethylene (181). A survey of such materials has been given (181). 

Fig. 1 Energy level diagram forthe zinc tetrabenzoporphyrin donor/chloroform acceptor system.

In comparison with MOEP and H2TPP, the increased planarity and tt conjugate system associated with the attached benzene rings on the pyrroles of porphyrin core render tetrabenzoporphyrins (TBPs) the most widely studied molecules among porphyrin derivatives for OFET devices. In 2004, Ono and co-workers... 

Single crystals of a number of other iodinated phthalocyanines, tetrabenzoporphyrins, and triazatetrabenzoporphyrins have also been prepared127,131,133, as have crystals of Co(pc)Br127,131. Typically, these compounds have the stoichiometry M(L)Ilo, and it is likely that the structures are the same as for Ni(pc)I and Ni(tbp)I. All these compounds conduct well, but with a variety of temperature responses. 

The enormous amount of work on phthalocyanins1 reflects their prime importance to the dye and pigment industry and is attested to by the numerous patents in the literature. It is our experience, however, that these materials are rarely pure and that their purification, from unknown impurities, is invariably more troublesome than performing the complete synthesis. Phthalocyanins are stronger o-donors than porphines, and the former stabilize higher oxidation states of coordinated metals,2 while the tetrabenzoporphyrins have properties more characteristic of porphines. 

Carter and co-workers demonstrated spectral hole burning via an intermolecular electron transfer mechanism. In this experiment poly (methyl methacrylate) (13) films were doped with zinc tetrabenzoporphyrin (14) electron donors and chloro-... 

Figure 3. Energy level diagram for the zinc tetrabenzoporphyrin donor-chloroform acceptor...

A number of reports on phthalocyanines and porphyrins have been published. Spectral diffusion and thermal recovery of spectral holes burnt into phthalocyanine doped Shpol skii systems has been examined . An absorption, emission, and thermal lensing research on carboxylated zinc phthalocyanine shows the influence of dimerization on these properties. Fourier transformation of fluorescence and phosphorescence spectra of porphine in rare gas matrices has yielded much structural and electronic state data on this compound . Exciton splitting is an effect which is seen in the spectra of covalently linked porphyrins . A ps fluorescence study of the semirigid zinc porphyrin-viologen dyad has provided evidence for two dyad conformers . Spectral diffusion in organic glasses has been measured by observing the hole recovery kinetics over the time scale of 1 to 500 ms for zinc tetrabenzoporphyrin in PMMA . 

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