Spiro porphyrin

More recently, porphyrinic azomethine ylide 28 (M = Ni) has been trapped with isatin to give a spiro porphyrin derivative 32 (Scheme 9) <06SC2655>. 

Because of its immense scope, a detailed description of corrins (and vitamin B12) will not be presented here. The reader is instead referred to reviews of B12 chemistry and its biosynthesis that have appeared recently. Further, because they are more directly related to the corrins than are the corroles, the chemistry of the dehydrocorrins will not be discussed here. Also not included in this review are the so-called artificial porphyrins of Floriani, et al. (e.g., 2.5), since it is deemed by these authors in their review that these macrocycles are more dehydrocorrin-like than corrole-like in their nature. Other systems omitted here include the spiro porphyrins of Battersby and coworkers, the tetraphosphole macrocycles of Mathey and coworkers and the tetrapyrrolic systems of Bartczak and Smith and co-workers. Thus, the emphasis will be on those contracted porphyrins that are most removed, in structural and chemical terms, from the macrocyclic unit found in coenzyme B12 and its analogs. 

Di- and tetra-9,9 -spirobifiuorene porphyrins 105-107, shown in Fig. 39, were synthesized by Poriel et al. [22]. These compounds show a hindered rotation about the porphyrin-spiro bond, which leads to the occurrence of at-ropisomers. Manganese and iron complexes of these spiro-porphyrins have been studied with respect to their properties as oxidation catalysts in heterogeneous catalysis [133,134]. 

For example, see T. G. Spiro, The resonance Raman spectroscopy of metalloporphyrins and heme proteins, in Iron Porphyrins (A. B. P. Lever and H. B. Gray, eds.), Part II. Addison-Wesley, Reading, MA, 1983. 

Key Words Ethylene oxide, Propylene oxide. Epoxybutene, Market, Isoamylene oxide. Cyclohexene oxide. Styrene oxide, Norbornene oxide. Epichlorohydrin, Epoxy resins, Carbamazepine, Terpenes, Limonene, a-Pinene, Fatty acid epoxides, Allyl epoxides, Sharpless epoxidation. Turnover frequency, Space time yield. Hydrogen peroxide, Polyoxometallates, Phase-transfer reagents, Methyltrioxorhenium (MTO), Fluorinated acetone, Alkylmetaborate esters. Alumina, Iminium salts, Porphyrins, Jacobsen-Katsuki oxidation, Salen, Peroxoacetic acid, P450 BM-3, Escherichia coli, lodosylbenzene, Oxometallacycle, DFT, Lewis acid mechanism, Metalladioxolane, Mimoun complex, Sheldon complex, Michaelis-Menten, Schiff bases. Redox mechanism. Oxygen-rebound mechanism, Spiro structure. 2008 Elsevier B.V. 

Su YO, Czemuczewicz RS, Miller LA, Spiro TG (1988) Effects of solvents, axial ligation, and radical cation formation on the V 0 stretching raman frequency in vanadyl porphyrins implications for peroxidase intermediates. J Am Chem Soc 110 4150-4157... 

Kincaid and Nakamoto observed the /(Fe-F) of Fe(OEP)F at 595 cm" with the 514.5 nm excitation. Kitagawa et al. also observed the (Fe-X) of Fe(OEP)X at 364 and 279 cm" for X = CI and Br, respectively and the y,(L-Fe-L) of [Fe(OEP)L2] (L= ImH) at 29axial vibrations can be enhanced via resonance with in-plane tt-tt transitions (a and /3 bands). According to the latter workers, vibrational coupling between these axial vibrations and totally symmetric in-plane porphyrin-core vibrations is responsible for their resonance enhancement. On the other hand, Spiro prefers electronic coupling, namely, the TT-TT transition induces the changes In the Fe-X (or L) distance, thus activating the axial vibration. 

Bands 1 and IV are an oxidation-state marker and a spin-state marker, respectively, ivhile Bands 11 and V are sensitive to both oxidation and spin states. Based on these results, Spiro and Strekas proposed thal the Fe-O bond in oxy-Hb should be formulated as Fe(lll)-Of. Bands I, II, IV, and V correspond to ihe v, w, and i/, , respectively, of Ni(OEP) shown in Fig. 111-16. According to normal coordinate calculations by Kitagawa el al. (Table 111-10), the oxidation-staie-sensiiive bands (1 3, P4, and p ) contain p(C C ) and p C C, ) or p(C N) as the major contrihutors in Iheir potential energy distribution. By lowering the oxidation state, back-donation of ti-electrons to the porphyrin tt orbital increases. Thus, the porphyrin 7r-bonds... 

Phthalocynanine-containing polymers are well-known [49] but till relatively recently, phthalocynanine-containing network polymers were generally rendered non-porous by strong non-covalent n-n stacking between sub-units. The introduction of contorted spiro centres allowed the preparation of phthalocynanine networks with BET surface areas in the range 500-1,000 m g (Fig. 6) [41,50]. These materials also demonstrated marked gas sorption hysteresis [50]. In the same study, dioxane-linked porphyrin network PIMs were produced with high BET surface areas (900-1,100 m g" ) [51]. An important aspect of these network polymers is their potential use in catalysis [52] (Sect. 4.1). 

Macor, K.A., YO. Su, L.A. Miller, and T.G. Spiro (1987). Electrochemical and resonance Raman-spectroscopic characterization of polyaniline and polyaniline metallo-porphyrin electrode films. Inorg. Chem. 26, 2594—2598. 

Piffat, C., D. Melamed, and T.G. Spiro (1993). Ruffling effect on porphyrin vibrations Normal mode analysis for nickel octaethyltetraphenylporphine from resonance Raman and Infrared spectra of isotopomers. J. Phys. Chem. 97,7441. 

Soldatova AV, Ibrahim M, Spiro TG (2013) Electronic structure and ligand vibrations in FeNO, CoNO, and FeOO porphyrin adducts. Inorg Chem 52 7478-7486... 

Spiro-linked CMPs functionalized with metal phthalocyanine units show enhanced catalytic activity towards different reactions." The Co-phthalocyanine-incorporated CMP acts as a catalyst with improved activity for cyclohexene oxidation, hydroquinone oxidation and H2O2 decomposition, whereas the spiro-linked Fe-porphyrin network shows increased catalytic activity for hydroquinone oxidation. The spiro linkages in these networks open up a lot of free space around the catalytic sites to enhance the accessibility of substrates to reach more catalytic sites. More functionalization in this vray of conjugated networks by various metals improves the scope of these networks in heterogeneous catalysis. Oxidation of sulfides, reductive aminations and photocatalyzed aza-Heniy reactions are reactions effectively catalyzed by different metal-incorporated CMPs" (Figure 10.6). 

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