Meso-Tetraphenylporphyrin

As an example heme-models have been reported to catalyze the epoxidation of olefins to the corresponding epoxides in good yield [16, 17]. In particular, [Fe TPP)Cl] (TPP = 5,10,15,20-meso-tetraphenylporphyrin) was reported to oxidize naturally occurring propenylbenzenes to the corresponding epoxides up to 98% selectivity (conversion 98%) using H2O2 as oxidant [16]. The major drawback... 

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... 

A heta-substituted porphyrin, such as hefa-nitro-meso-tetraphenylporphyrin le, also reacts with o-benzoquinodimethane to give the corresponding nitrochlorin 2e, together with the naphthoporphyrin 4a and the bis-naphthoporphyrin (bisadduct) 7 the formation of these 4a and 7 derivatives imply HNO2 elimination and dehydrogenation reactions <06TL8437>. 

In 1995, Boyd and co-workers <95TL7971 > covalently linked a porphyrin to fullerene Cgo through a 1,3-dipolar cycloaddition reaction involving the porphyrinic azomethine ylide 28 (Scheme 8). The ylide was generated in situ from befa-formyl-meso-tetraphenylporphyrin 27 and A -methylglycine, and provided the porphyrin-C6o diad 29 in good yield. 

Extension of the 1,3-DC approach to the synthesis of novel pyrazoline-fused chlorin 78 by the reaction of P-nitro-meso-tetraphenylporphyrin le with diazomethane has also been explored by Cavaleiro and co-workers (Scheme 27) <02S 1155>. The resulting chlorin 78 could be further converted into the pyrazole-fused porphyrin 79 by treatment with DBU or into the methanochlorin 80 by refluxing in toluene. 

A.V. Kashevskii, J. Lei, A.Y. Safronov, and O. Ikeda, Electrocatalytic properties of meso-tetraphenylporphyrin cobalt for nitric oxide oxidation in methanolic solution and in Nafion film. J. 

In order to prepare and isolate solid-state, crystalline, oxygenated iron-heme model complexes, chemists learned to synthesize (by self-assembly methods) and oxygenate many types of hindered porphyrins. For instance, capped porphyrins were synthesized by direct condensation of a suitable tetraaldehyde with four pyrrole molecules.37 Picket-fence porphyrins such as I e(TPP)((V-MeIm) (where TPP = meso-tetraphenylporphyrin and /V-Melm = (V-methylimidazole)... 

Time-resolved fluorescence studies were also carried out on a series of zinc(II) complexes of meso-tetraphenylporphyrins covalently linked to 1,3-dinitrobenzene and 1,3,5-trinitrobenzene as acceptors to study the photoinduced electron transfer process, which is the initial process for the photosynthesis10. 

Shimada et al. (3) first found that a synthetic porphyr., non meso-tetraphenylporphyrin (FeTPP (I)) catalyzed C-C bond cleavage of/ -l type... 

The rhodium complex [CpRh(bipy)Cl2] is reported (162) to act as one-half of a redox couple that, in concert with a manganese porphyrin system, catalyzes the epoxidation of olefins by dioxygen. In this two-phase system, the aqueous phase contains sodium formate, and the organic phase is a trichloroethane solution of [Mnm(tpp)]1+ and the rhodium complex (tpp = meso-tetraphenylporphyrin). Apparently, the rhodium complex catalyzes the reduction of [Mnin(tpp)]1+ by formate, and the manganese(II) species thus formed binds dioxygen and reacts with the substrate olefin to form the epoxide. However, the intermedi-... 

The meso-tetraphenylporphyrin complex [Zr(TPP)Cl2] has been prepared by reaction of H2TPP with ZrCl4 in boiling benzonitrile. The electronic spectrum of [Zr(TPP)Cl2] and the facile kinetics of TPP dissociation in acidic media suggest that the zirconium atom lies considerably out of the plane of the TPP ligand with both chlorine atoms being located on the same side of the TPP plane.708... 

The properties of [MoOCl(TPP)] (H2TPP = meso-tetraphenylporphyrin) and related complexes are covered in Section 36.4.3.2.4. 

Temperature not reported. 1 Rjdt — 4-morpholinodithiocarboiylate. 11TPP = dianion of meso-tetraphenylporphyrin. 

Except for a few examples [103], see below, the focus of synthetic P450 chemistry has been on the meso-tetraphenylporphyrin system mainly because free meso-positions can easily be oxidized in the presence of O donors employed in the shunt pathway . 

NMO NMP Nu PPA PCC PDC phen Phth PPE PPTS Red-Al SEM Sia2BH TAS TBAF TBDMS TBDMS-C1 TBHP TCE TCNE TES Tf TFA TFAA THF THP TIPBS-C1 TIPS-C1 TMEDA TMS TMS-C1 TMS-CN Tol TosMIC TPP Tr Ts TTFA TTN N-methylmorpholine N-oxide jV-methyl-2-pyrrolidone nucleophile polyphosphoric acid pyridinium chlorochromate pyridinium dichromate 1,10-phenanthroline phthaloyl polyphosphate ester pyridinium p-toluenesulfonate sodium bis(methoxyethoxy)aluminum dihydride (3-trimethylsilylethoxy methyl disiamylborane tris(diethylamino)sulfonium tetra-n-butylammonium fluoride f-butyldimethylsilyl f-butyldimethylsilyl chloride f-butyl hydroperoxide 2,2,2-trichloroethanol tetracyanoethylene triethylsilyl triflyl (trifluoromethanesulfonyl) trifluoroacetic acid trifluoroacetic anhydride tetrahydrofuran tetrahydropyranyl 2,4,6-triisopropylbenzenesulfonyl chloride 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane tetramethylethylenediamine [ 1,2-bis(dimethylamino)ethane] trimethylsilyl trimethylsilyl chloride trimethylsilyl cyanide tolyl tosylmethyl isocyanide meso-tetraphenylporphyrin trityl (triphenylmethyl) tosyl (p-toluenesulfonyl) thallium trifluoroacetate thallium(III) nitrate... 

Many examples are known in which multiple components are brought together about a metal ion to form macrocyclic complexes. Typical examples include the formation of meso-tetraphenylporphyrin (6.21) from benzaldehyde and pyrrole (Fig. 6-20, [4+4]), or phthalocyanine (6.6) from phthalonitrile (Fig. 6-21). The formation of the tetraphenyl-porphyrin is catalysed by a range of Lewis acids, and the facile preparation from aldehydes and pyrroles has obvious implications for the bioevolution of porphyrin pigments. Virtually any benzene derivative with ortho carbon-bearing substituents can be converted to a phthalocyanine complex on heating with a metal or metal salt in the presence of ammonia or some other nitrogen source. 

Figure 6-20. The [4+4] condensation of benzaldehyde and pyrrole in the presence of Lewis acids yields meso-tetraphenylporphyrin.

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