Metal salophen

Oligosaccharide-salicylaldehyde conjugates 5-8 (Table 15.1) are ready for one-step metal-salophen hydrosoluble complex formation by metal-templated reductive amination with 1,2-diaminobenzene. 

A mild aerobic palladium-catalyzed 1,4-diacetoxylation of conjugated dienes has been developed and is based on a multistep electron transfer46. The hydroquinone produced in each cycle of the palladium-catalyzed oxidation is reoxidized by air or molecular oxygen. The latter reoxidation requires a metal macrocycle as catalyst. In the aerobic process there are no side products formed except water, and the stoichiometry of the reaction is given in equation 19. Thus 1,3-cyclohexadiene is oxidized by molecular oxygen to diacetate 39 with the aid of the triple catalytic system Pd(II)—BQ—MLm where MLm is a metal macrocyclic complex such as cobalt tetraphenylporphyrin (Co(TPP)), cobalt salophen (Co(Salophen) or iron phthalocyanine (Fe(Pc)). The principle of this biomimetic aerobic oxidation is outlined in Scheme 8. 

The two oxygen-activating complexes [Co(L)j [L = salophen, tetra-tert-butylsalo-phen (55)] have been prepared and were also synthesized within dehydrated zeolite NaY using the intrazeolite ligand synthesis method [164]. These encapsulated metal complexes were shown to be capable of oxidizing hydroquinone and so were then used in a triple catalytic system to mediate the palladium-catalyzed aerobic 1,4-diacetoxylation of 1,3-dienes (Figure 5.28) [165]. The catalytic system involved [Pd(OAc)2], hydroquinone and the [Co(salophen)] complex in acetic acid (Co Pd diene hydroquinone LiOAc = 1 2.23 50 8.3 690, acetic acid, 25 °C,... 

The alkali metals Li and Na promote the dimerization of the complex N,N -o phenylenebis(salicylideneiminato)nickel(II), [Ni(salophen)], by means of the reductive coupling of two imino groups between two Ni(salophen) molecules (Scheme 29).2352... 

Recently, there is a unique Mb reconstituted with the non-porphyrinoid metal complex. Watanabe and co-workers successfully inserted [Crra(salo-phen)]+ (salophen N, A -bis(salicylidene)-l,2-phenyl-enediamine into apoMb to yield a semisynthetic metalloenzyme (88). They used a H64D/A71G mutant as the apoprotein, because the H64D mutation may allow easy access of a substrate and oxidant and the A71G mutation increases the binding affinity of... 

The majority of the devices mentioned thus far rely on the Hofmeister series for anion selectivity. However, for anions that deviate from this series, organometallic receptors can be utilised. The type of ligand or metal centre will influence the sensor selectivity due to the characteristics of the electron acceptance of the complex. An interesting development that is being explored here is the use of calixarenes. These have previously found use as cation-selective species, but with suitable substitution are now being incorporated within anion-selective devices. Compounds suitable as receptors for halides [61],benzoate [61] and acetate [62] have been developed. Reinhoudt and his co-workers have reported the production of a POj-selective CHEMFET based on a uranyl cation immobilised within a salophene ligand (Fig. 5), which shows selectivity over more lipophilic anions such as Br" and NOj [63]. 

The activities of the zeolite-encapsulated catalysts were compared to the fi ee complexes. In the oxidation of hydroquinone to benzoquinone the amount of Co-salophen/zeolite catalyst just necessary for the same reaction rate as in the case of fi ee metal complex was used. The same amount of catalysts was used for the triple catalytic oxidation reactions, too. 

Screening of an impressive series of polymers derived from different bulky methacrylate esters, e.g., 42 (Chart 8), and using a variety of chiral ligands has revealed the scope of the process of forming helical poly(methacrylate ester)s and their applicability in, for example, the separation of chiral compounds.151 These polymers were prepared not only by anionic polymerization, but also by cationic, free-radical, and Ziegler—Natta techniques. Recently, Nakano and Okamoto reported the use of a co-balt(II)—salophen complex (43) in the polymerization of methacrylate ester 41.155 The free-radical polymerization in the presence of this optically active metal complex resulted in the formation of an almost completely isotactic polymer with an excess of one helical sense. 

Several metal macrocycles, like iron phthalocyanine and cobalt salophen were tested in these palladium-catalyzed aerobic oxidation of olefins and dienes. These tnacrocycles were able to activate the molecular oxygen, but in the homogeneous system several problems have arised, such as poor solubility, self-degradation and the difficulty to reuse theses complexes. A... 

Analysis of the cobalt content allowed the determination of the amount of cobalt(salophen) present in the zeolite. It was found that the metal content of the zeolite was 0.485 mmol/g catalyst. 

The chiral framework that has been the centerpiece of the development of metal salens as asymmetric oxidation catalysts (224, 225) cannot be installed in the HSX platform since the acid functionalized xanthene is bound to a salophen... 

Asfari, Z. Thuery, P. Nierlich, M. Vicens. J. Unsym-metrical calix[4]- /5-crowns-6 with unequivalent crown loops. Tetrahedron Lett. 1999. 40. 499-502. van Axel Castelli. V. Cort, A.D. Mandoliai. L. Rein-houdt, D.N. Schiaffino. L. Catalysis of the addition of benzenethiol to 2-cyclohexen-I-ones by uranyl-salophen complexes A catalytic metallocleft with high substrate specificity. Chem. Eur. J. 2000, 6. 1193-1198. Albrecht, M. Hovestad, N.J. Boersma, J. van Koten. G. Multiple use of soluble rnetallodendritic materials as catalysts and dyes. Chem. Eur. J. 2001, 7. 1289-1294. Haino. T. Araki. H. Yamanaka. Y. Fukazawa, Y. Fullerene receptor based on calix[5]arene through metal-assisted self-assembly. Tetrahedron Lett. 2001. 42, 3203-3206. 

Coordination compounds of metals incorporated in polyorganosiloxane matrices. XIII. (Co)(II) complexes with salen salophen and molecular oxygen... 

Early contributions in this area came from Reinhoudt s group and refer to cases in which the ion-pair-binding mechanism is of the host-separated type (Figure 19c) (for original references see reviews ). They first exploited cone calix[4]arene tetraesters or 1,3-alternate calix[4] crowns as binding units for alkali metal ions and uranyl-salophen complexes as anion-binding sites. 

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