Porphyrin complexes research

Porphyrin-metal complexes are natural mimetic substances that have attracted much attention during the past decade. The epoxidation of olefins by porphyrin complexes proceeds well, but with only modest enantioselectivity. As this area of research is growing, description of a few selected publications may be useful.96... 

These researchers found that the nucleophilicity of the complex depended on the electronic nature of the porphyrin. While a [(TPFPP)Fe (02)] (TPFPP equals the dianion of me5 o-tetrakis(pentafluorophenyl)porphyrin) complex did not epoxidize alkenes, adding dimethylsulfoxide (DMSO) as an axial ligand restored the complexes nucleophilicity and ability to epoxidize alkenes. The authors ascribed this restored capability to push the side-on peroxo into a more open, end-on, nucleophilic conformation. Watanabe and co-workers... 

Phthalocyanine complexes are organic macrocycles with 18 7t-electrons, structurally resembling the naturally-occuring porphyrins complexes [1-3], Electrodes modified with transition metal (notably Fe, Co, Mn, Ni) phthalocyanine (MPc, Fig.l) complexes have continued to generate immense research interests because of their well-established electrocatalytic properties [3-6],... 

The discussion of porphyrin complexes in the activation of dioxygen in solution can be readily subdivided into discussions of monomeric systems and dimeric systems. The dimeric systems (cofacial metallodi-porphyrins) have recently been reviewed by Collman, Wagenknecht, and Hutchison (73). That review highlights the significant amount of research stimulated by the initial discovery by Collman and co-workers (74), confirmed later by Chang and co-workers (75), that dicobalt cofacial diporphyrins can promote the direct four-electron reduction of dioxygen to water. 

In 2009, our research interest in the interaction of NO, molecules with metaUoporphyrins was extended to investigating the role of the heme active site independent of the nonheme site in the mechanism of action of the NORs. To this end, we sought to prepare and isolate the hyponitrite-bridged porphyrin complex [(0EP)Fe]2(A<-N202). The [(0EP)Fe]2(//-N202) complex was successfully prepared by treating a toluene solution of (OEP)Fe-(OMe) or the oxo-dimer complex [(0EP)Fe]2( -0) with hyponitrous acid (Equations 10 and 11) which may be viewed as a category 3 hyponitrite complex synthesis. See Section 3.4.1. 

Several researchers have reported on the use of porphyrin complexes as... 

Results of carried out researches demonstrate the possibility of receiving the lanthanide porphyrin complexes by use of microwave radiation technique. Thus, the time of process is considerably reduced, energy consumptions decreased, reactions are carried out at lower temperatures, there is no need for an inert atmosphere. 

Several research groups reported that various ILs could be effective cocatalysts in the copolymerization of CO2 and epoxides with metal salen or metal porphyrin complexes [126-130]. In some cases, it was shown that the activities of theses metal complexes were drastically enhanced by the co-presence of IL, although they had no or a very low activity for the coplymerization in the absence of IL. 

Chemical transformations at the macroeyclic chromophorc of expanded porphyrins are still not known. The complexation behavior of expanded porphyrins is very different from that of nonexpanded porphinoid macrocycles. The coordination hole of the expanded porphyrins is often too big for the complexation of a single metal ion, so in fact two metal ions can be chelated. With some expanded porphyrins, anion binding is observable, a striking difference to the nonexpanded porphyrins. The complexation behavior and the host-guest chemistry of expanded porphyrins is a rapidly growing field of research. The work in this field has been reviewed. Ie f... 

A key step proposed in the radical chain mechanism for the formation of the formyl complex is the coordination of CO to the Rh(OEP)- monomer, to give an intermediate carbonyl complex, Rh(OEP)(CO)- which then abstracts hydride from Rh(OEP)H to give the formyl product.This mechanism was proposed without direct evidence for the CO complex, and since then, again from the research group of Wayland, various Rh(fl) porphyrin CO complexes, Rh(Por)(CO), have been observed spectroscopically along with further reaction products which include bridging carbonyl and diketonate complexes. 

---