Tetraphenyl zinc porphyrin

The covalent anchoring of a benzo-15-crown-5 moiety to the meta or para phenolic oxygen of a zinc tetraphenyl porphyrin via ether formation has produced m-29 and p-29, respectively. These heteroditopic receptors can bind NaCN in a ditopic fashion with a visible color change, in contrast with other sodium salts (including F, CF, BF, I-, and SCN-), which are bound in a monotopic fashion without a color change <2002CC512>. 

Another dyad was obtained by the axial complexation of zinc tetraphenyl-porphyrin by a pyridine Ceo derivative as shown in Scheme 14.14 [268]. 

The donor-acceptor complexes formed between electron acceptors (such as iodine or tetracyanoethylene) and electron donors (such as aliphatic amines or aromatic hydrocarbons) have, been extensively studied from various points of view -spectroscopic 5 structural and thermodynamic (3). Kinetic investigation has lagged behind, because the reactions are extremely fast and the equilibrium constants small the rate constant of one such reaction had been measured by means of our microwave apparatus (without the recent improvements), at -83 C (U). We have now determined rate constants, in 1-chlorobutane, as solvent for the reactions of zinc tetraphenyl-porphyrin with pyridine and 2-methyl pyridine, which have been well characterised by spectrophotometric methods (5, 6). They are less than the diffusion-controlled value by an order of magnitude. Further investigations are in progress. 

Recently, spherical porphyrin arrays were assembled through coordina-tive interaction between a dendrimer bearing 16 pyridyl-terminated units and zinc porphyrins [125]. Detailed investigation revealed that this pyridyl dendrimer is unable to form stable assemblies with simple zinc tetraphenyl-porphyrin, while a globular macromolecular assembly containing 12 terminal porphyrins is supposed to be formed by the coordination with a porphyrin trimer. 

The zinc(II) complexes of meso-tetraphenyltetrabenzoporphyrin (38) and of meso-tetraphenyl-tetranaphthoporphyrin (39) have been prepared 173-175 some photophysical properties of this interesting series are given in Table 11176 Photooxidation of zinc(II) porphyrins causes cleavage of the macrocycle with formation of bilinone derivatives.122 206 207... 

Pertinent to this discussion are recent studies on porphyrin- r-oation radicals derived from magnesium and cobaltic octaethyl porphyrins (171, 172), and zinc and magnesium tetraphenyl porphyrins (J71). In all cases, the optical spectra of such radicals share features also found in Compound I (Fig. 7). These are (a) a decrease of w-w transitions associated with the Soret band and (b) the appearance of bands between 600 and 700 nm. The chief objection to the proposal implicating a free radical moiety stems from the absence of a distinct EPR signature for Compound... 

One of the first reported Ceo-based donor-acceptor systems is also the H2P-C60 and the analog ZnP-Cso dyad (20), in which H2P denotes the metal-free base tetraphenyl porphyrin and ZnP is the corresponding zinc tetraphenylporphyrin... 

Whitlock et al. developed a new method to synthesize bacteriochlorins and isobacteriochlorins selectively it involved diimide reduction of porphyrins. 2 Di-imide reduction of metal-free tetraphenyl-chlorin H2(TPC) afforded tetraphenyl-bacteriochlorin H2(TPBC) 140 in 84% yield, while reduction of zinc tetraphenyl-chlorin Zn(Xrc) produced the Zn(II) complex of tetraphenyl-isobacteriochlorin 141 in 57% yield (Scheme 40). 

Figure 13 Schematic representation of a family of dedrimers having a tetraphenyl porphyrin as a core and four identical dendronized wedges containing a variable number of zinc porphyrins. (Reprinted by permission of John Wiley Sons, Inc. from Ref. 31.)...

Figure 9 (a) Conceptualized depiction of metal tetraphenyl porphyrin (M-TPP) jt ji stacking to a SWNT. (b) Structure of zinc... 

Porphyrin, tetrahydro-metal complexes geochemistry. 6, 862 Porphyrin, tetraphenyl-indium complexes radiopharmacology, 6, 971 iron complexes, 4, 260,1266 zinc complexes spectra, 6, 617... 

Having previously discussed the lack of redox activity of Zn(II) derivatives (Chapter 5, Section 8), we shall start with zinc-porphyrins. Figure 50 shows the planar geometry of Zn(II)-5,10,15,20-tetraphenyl-porphyrininato complex, [Zn(TPP)].91,92... 

The photoinduced reduction of some quinones by zinc porphyrin and also by its tetraphenyl derivative has been studied in micellar systems. The mean time for intramicellar electron transfer has been established as 0.2 ps, and for duroquinone the rates of entry and exit from the micelle have been found to be 5 x 10 m s and6 x 10 m s respectively. Quinones possessing long chains are less mobile and partial charge separation could be achieved. Irradiation of anthraquinone in aqueous sodium dodecyl sulphate leads to anthraquinol and the surfactant-anthrahydroquinone ether as major products via the triplet state of the anthraquinone. ... 

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