Iron complexes supramolecular

The interest in polynuclear supramolecular iron complexes mainly arises from the importance of oxo-centered polyiron aggregates as model compounds for iron-oxo proteins. In principle, / 3-oxo-centered complexes related to [Fe30(02CR)6(H20)3] [11] should also be accessible with doubly negatively charged bis-bidentate ligands. 

THE ROLE OE SUPRAMOLECULAR NANOSTRUCTURES EORMATION IN THE MECHANISMS OF HOMOGENOUS AND ENZYMATIC CATALYSIS WITH NICKEL OR IRON COMPLEXES... 

Supramolecular polymers which iron-complexes along the anionic main chain were complexed with cationic block copolymers (Fig. 23) [272,273]. However, the applied redox reaction hardly changed the micellar morphologies, although the payload could be released and entrapped upon a chemical redox stimulus. Similarly, nanoparticles were developed for the redox-triggered release of drugs (here by redox-induced scission of polymer-attached trimethyl-locked benzoquinone) [274],... 

Chiper M, Meier MAR, Kranenburg JM, Schubert US. New insights into nickel(II), iron(II), and cobalt(II) bis-complex-based metaUo-supramolecular polymers. Macromol Chem Phys 2007 208 679-689. 

A chromophore such as the quinone, ruthenium complex, C(,o. or viologen is covalently introduced at the terminal of the heme-propionate side chain(s) (94-97). For example, Hamachi et al. (98) appended Ru2+(bpy)3 (bpy = 2,2 -bipyridine) at one of the terminals of the heme-propionate (Fig. 26) and monitored the photoinduced electron transfer from the photoexcited ruthenium complex to the heme-iron in the protein. The reduction of the heme-iron was monitored by the formation of oxyferrous species under aerobic conditions, while the Ru(III) complex was reductively quenched by EDTA as a sacrificial reagent. In addition, when [Co(NH3)5Cl]2+ was added to the system instead of EDTA, the photoexcited ruthenium complex was oxidatively quenched by the cobalt complex, and then one electron is abstracted from the heme-iron(III) to reduce the ruthenium complex (99). As a result, the oxoferryl species was detected due to the deprotonation of the hydroxyiron(III)-porphyrin cation radical species. An extension of this work was the assembly of the Ru2+(bpy)3 complex with a catenane moiety including the cyclic bis(viologen)(100). In the supramolecular system, vectorial electron transfer was achieved with a long-lived charge separation species (f > 2 ms). 

When triethanolamine H3L13 (35) was reacted with sodium hydride and iron(III) chloride, the hexanuclear centrosymmetric ferric wheel [Nac Fe6(L13)6 )Cl (36) was isolated. Amidst a set of possibilities in the template-mediated self-assembly of a supramolecular system, the one combination of building blocks is realized that leads to the best receptor for the substrate [112]. Therefore, the six-membered cyclic structure 36 is exclusively selected from all the possible iron triethoxyamine oligomers, when sodium ions are present. The iron(III) complex 36 is present as an Sg-symmetric wheel, with an encapsulated sodium ion in the center and a chloride counterion. Consequently, the trianion (L13)3- acts as a tripodal, tetradentate, tetratopic ligand, which each links three iron(III) ions and one sodium ion. In the presence of cations with different ionic radii, different structures are expected. Therefore, when triethanolamine H3L13 (35) was reacted with cesium carbonate and iron(III) chloride, the octanuclear centrosymmetric ferric wheel [Csc Fe8(L13)8 ]Cl (37) was isolated (Scheme 13) [113]. 

Most of the components involved in electron transport in mitochondria are contained in four supramolecular protein complexes that traverse the inner mitochondrial membrane. Complex I, which contains FMN and various iron-sulfur clusters as active sites, transfers electrons from NADH to ubiquinone (Fig. 6-8). Complex II, which contains FAD, various iron-sulfur clusters, and a Cyt >, transfers electrons from succinate also to a ubiquinone. Ubiquinone functions as a pool of two-electron carriers, analogous to the function of plastoquinone A in the lamellar membranes of chloroplasts, which accepts electrons from Complexes I and II and delivers them to the... 

Krische MJ, Lehn JM (2000) The Utilization of Persistent H-Bonding Motifs in the Self-Assembly of Supramolecular Architectures. 96 3-30 Krumholz P (1971) Iron(II) Diimine and Related Complexes. 9 139-174 Kuhn FE, Herrmann WA (2000) Rhenium-Oxo and Rhenium-Peroxo Complexes in Catalytic Oxidations. 97 213-236 Kubas GJ, see Ryan RR (1981) 46 47-100 Kuki A (1991) Electronic Tunneling Paths in Proteins. 75 49-84... 

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