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Crown ether-porphyrins

Chelation itself is sometimes useful in directing the course of synthesis. This is called the template effect (37). The presence of a suitable metal ion facihtates the preparation of the crown ethers, porphyrins, and similar heteroatom macrocycHc compounds. Coordination of the heteroatoms about the metal orients the end groups of the reactants for ring closure. The product is the chelate from which the metal may be removed by a suitable method. In other catalytic effects, reactive centers may be brought into close proximity, charge or bond strain effects may be created, or electron transfers may be made possible. [Pg.393]

B. Iron Complex of a Crown Ether-Porphyrin Conjugate Suitable for... [Pg.59]

The combination of crown ether and porphyrin has also been carried out by Bogatskii et al. , who have prepared the ffi o-tetra(benzo-18-crown-6)porphyrin 223 by two routes (Scheme 66). Condensation of 4 -formylbenzo-18-crown-6 220 with pyrrole in refluxing acetic acid or reaction of tetra(3,4-dihydroxyphenyl)porphyrin (221) with the dichloride 222 provided the tetra-crown ether porphyrin 223 in 4% and 10% yield respectively. This compound is reported to form complexes with transition and group I, II metals. [Pg.186]

Calcium-binding proteins, 6, 564, 572, 596 intestinal, 6, 576 structure, 6, 573 Calcium carbonate calcium deposition as, 6, 597 Calcium complexes acetylacetone, 2, 372 amides, 2,164 amino acids, 3, 33 arsine oxides, 3, 9 biology, 6, 549 bipyridyl, 3, 13 crown ethers, 3, 39 dimethylphthalate, 3, 16 enzyme stabilization, 6, 549 hydrates, 3, 7 ionophores, 3, 66 malonic acid, 2, 444 peptides, 3, 33 phosphines, 3, 9 phthalocyanines, 2,863 porphyrins, 2, 820 proteins, 2, 770 pyridine oxide, 3,9 Schiff bases, 3, 29 urea, 3, 9... [Pg.97]

Fig. 3a,b. Template cyclization reactions of a crown ethers and b CPOs. The coordination bonds are illustrated by black arrows. In the crown ether synthesis, ethylene glycols coordinate toward the metal acting as the template (normal template reaction) however, the template coordinates to the incorporated metals of porphyrin In CPO synthesis (inverse-template reaction)... [Pg.72]

A methanofullerene derivative possessing an ammonium subunit has been prepared and subsequently shown to form a supramolecular complex with a porphyrin-crown ether conjugate <06T1979>. The synthesis and study of these fullerene-containing supramolecular photoactive devices have also been reported <06CRC1022>. [Pg.468]

D Souza, F., et al., Self-assembled single-walled carbon nanotube-.Zinc-porphyrin hybrids through ammonium ion-crown ether interaction Construction and electron transfer. Chemistry - A European Journal, 2007.13(29) p. 8277-8284. [Pg.159]

The study of the complexing of macrocycle ligands should be considered for its intrinsic importance rather than for its value in illuminating the mechanism of substitution. Kinetic (but much more thermodynamic °) data are available for the reactions of the different macrocycle ligand types, shown in Fig. 4.5, including azamacrocycles,crown ethers and cryp-tands, and porphyrins. ... [Pg.224]

Reaction of 175 with Cgg yields a hydroxy-functionalized fullerene that can be further derivatized. This hydroxy-fullerene was coupled with a porphyrine unit via a polyethyleneglycol-Hnker. This linker can be arranged similarly to a crown-ether to complex metal cations. Complexation is used to tune the distance between the porphyrin imit and the Cgg-moiety and thus tune the donor-acceptor properties of this porphyrin-fuUerene hybrid [177]. [Pg.138]

The conjugation in the molecular wire may be disrupted or modulated to create systems with different properties. For example, a porphyrin Ceo donor-acceptor system linked with a conjugated binaphthyl unit, has a preference for the atropi-somer where the fullerene unit is closer to the porphyrin system, thus increasing the through space interactions [82]. The charge transfer process on a dyad containing a crown ether in the linker structure can be modulated by complexation/ decomplexation of sodium cations [83] but even more interesting is the construction of supramolecular systems where the donor and acceptor moieties are... [Pg.135]

Porphyrin-based self-assembled molecular squares 389 can form mesoporous thin films in which the edge of a square, thus the size of the cavity, can be adjusted by appropriate choice of substituents [8]. Fibers that form coil-coiled aggregates with distinct, tunable helicity are built from crown ethers bearing porphyrins 390 [9]. In addition to the porphyrin applications discussed in Sections 6.3.2.2 and 6.4, dendrimer metalloporphyrins 391 to be applied in catalysis [10] and the water-soluble dendritic iron porphyrin 319 modelling globular heme proteins [11] can be mentioned. [Pg.270]


See other pages where Crown ether-porphyrins is mentioned: [Pg.384]    [Pg.89]    [Pg.316]    [Pg.1295]    [Pg.143]    [Pg.2620]    [Pg.384]    [Pg.89]    [Pg.316]    [Pg.1295]    [Pg.143]    [Pg.2620]    [Pg.592]    [Pg.749]    [Pg.907]    [Pg.100]    [Pg.144]    [Pg.156]    [Pg.203]    [Pg.224]    [Pg.232]    [Pg.123]    [Pg.334]    [Pg.341]    [Pg.70]    [Pg.72]    [Pg.68]    [Pg.281]    [Pg.466]    [Pg.207]    [Pg.384]    [Pg.89]    [Pg.89]    [Pg.273]    [Pg.144]    [Pg.106]    [Pg.352]    [Pg.356]    [Pg.59]    [Pg.246]    [Pg.251]    [Pg.269]   
See also in sourсe #XX -- [ Pg.275 ]




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