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1.10- Phenanthroline catalysis

In contrast, investigation of the effect of ligands on the endo-exo selectivity of the Diels-Alder reaction of 3.8c with 3.9 demonstrated that this selectivity is not significantly influenced by the presence of ligands. The effects of ethylenediamine, 2,2 -bipyridine, 1,10-phenanthroline, glycine, L-tryptophan and L-abrine have been studied. The endo-exo ratio observed for the copper(II)-catalysed reaction in the presence of these ligands never deviated more than 2% from the endo-exo ratio of 93-7 obtained for catalysis by copper aquo ion. [Pg.91]

Holmium, tris(2,2,6,6-tetramethyl-3,5-heptanedione)-photosubstitution, 1,408 Holmium complexes 1,3-diketones, 2,387 phenanthroline, 3,1069 Homoazaporphyrins synthesis, 2, 817 Homolytic cleavage catalysis... [Pg.139]

Preparation by oxidising tris(phenanthroline)cobalt(III) tetrafluoroborate with nitric acid in sulfuric acid with potassium bromide catalysis is potentially explosive. See Nitric acid... [Pg.1182]

A few additional Pd-catalyzed schemes have been employed for Ilac type cyclization chemistry. Palladium-phenanthroline complexes were used by the Ragaini group to prepare indoles via the intermolecular cyclization of nitroarenes and alkynes in the presence of carbon monoxide <06JOC3748>. Jia and Zhu employed Pd-catalysis for the annulation of o-haloanilines with aldehydes <06JOC7826>. A one-pot Ugi/Heck reaction was employed in the preparation of polysubstituted indoles from a four-component reaction system of acrylic aldehydes, bromoanilines, acids, and isocyanides <06TL4683>. [Pg.155]

Considerable attention has been paid to this transformation (which is sometimes referred to as hydration ) in the past 15 years. 2. early example of the effect was the marked acceleration of the base hydrolysis of 2-cyanophenanthroline by Ni +, Cu + and Zn " " ions. The second-order rate constant is lO -fold higher for the Ni complex than for the free ligand, residing mainly in a more positive AS An external OH attack on the chelate was favored but an internal attack by Ni(II) coordinated OH cannot be ruled out. Nickel-ion catalysis of the hydrolysis of the phenanthroline-2-amide product is much less effective, being only about 4 x 10 times the rate for spontaneous hydrolysis. ... [Pg.313]

In 17, X may be POj (but COCH3, SO3 and other groups have also been examined by this means). In the type of structure shown in 18 we have already encountered the 2-nitrile hydrolyses. With X = POf in 18, divalent metal ions show a pronounced catalysis of the hydrolysis of the dianionic species. The metal is strongly chelated to the phenanthroline but in the product it is unlikely that the 0 is coordinated since a four-membered ring would result (see Sec. 6.8). The monoanionic form (X = POjH ) is the reactive species (Prob. 3). Reaction of the dianion in the absence of metal ion cannot be observed and with Cu +, for example, accelerating effects of >10 are estimated. ... [Pg.316]

More synthetic interest is generated by the potentially very useful hydration of dienes. As shown on Scheme 9.6, methylethylketone (MEK) can be produced from the relatively cheap and easily available 1,3-butadiene with combined catalysis by an acid and a transition metal catalyst. Ruthenium complexes of several N-N chelating Hgands (mostly of the phenanthroline and bipyridine type) were found active for this transformation in the presence of Bronsted acids with weakly coordinating anions, typically p-toluenesulfonic acid, TsOH [18,19]. In favourable cases 90 % yield of MEK, based on butadiene, could be obtained. [Pg.223]

SDS), and indeed SDS-catalysis of Hg " -catalyzed replacement of cyanides in [Fe(C1 6]" 1 1,10-phenanthroline has been proposed as an analytical method for the determination of mercury. ... [Pg.422]

Applications for the 1,10-phenanthroline nucleus are widespread for example, they have been used as chelating agents (see Section 10.23.5.2), ligands for catalysis (see Section 10.23.5.2), as cytotoxic drugs <2002T9095>, and, when complexed with molybdenum, as cancer therapeutics <2005W0087783>. [Pg.1263]

The NAD+-dependent alcohol dehydrogenase from horse liver contains one catalytically essential zinc ion at each of its two active sites. An essential feature of the enzymic catalysis appears to involve direct coordination of the enzyme-bound zinc by the carbonyl and hydroxyl groups of the aldehyde and alcohol substrates. Polarization of the carbonyl group by the metal ion should assist nucleophilic attack by hydride ion. A number of studies have confirmed this view. Zinc(II) catalyzes the reduction of l,10-phenanthroline-2-carbaldehyde by lV-propyl-l,4-dihy-dronicotinamide in acetonitrile,526 and provides an interesting model reaction for alcohol dehydrogenase (Scheme 45). The model reaction proceeds by direct hydrogen transfer and is absolutely dependent on the presence of zinc(II). The zinc(II) ion also catalyzes the reduction of 2- and 4-pyridinecarbaldehyde by Et4N BH4-.526 The zinc complex of the 2-aldehyde is reduced at least 7 x 105 times faster than the free aldehyde, whereas the zinc complex of the 4-aldehyde is reduced only 102 times faster than the free aldehyde. A direct interaction of zinc(II) with the carbonyl function is clearly required for marked catalytic effects to be observed. [Pg.475]

The chemical reactivity of 2,2 -bipyridyl anion-radicals has recently attracted attention in a comparative study, again with 1,10-phenanthroline, the rates of exchange of ring protons for D at 100° were determined and related to their catalysis of equilibration of H2-D2.114 Others have made a mechanistic study of the same reaction.115... [Pg.236]

Phase transfer catalysis, applications in heterocyclic chemistry, 36, 175 Phenanthridine chemistry, recent developments in, 13, 315 Phenanthrolines, 22, 1 Phenothiazines, chemistry of, 9, 321 Phenoxazines, 8, 83 Photochemistry of heterocycles, 11, I of nitrogen-containing heterocycles, 30, 239... [Pg.348]

The most interesting catalytic data available are those of Rund et al. (608, 609) on the catalyzed decarboxylation of dimethyloxalacetic acid. Phenanthroline enhances Mn(II) and Ni(II), but not Zn(II) and Mg(II) catalysis, while ligand substituents appear to alter the ratedetermining step. The catalytic process suggested is... [Pg.158]

It was suggested that the addition of 1,10-phenanthroline or dba as ligands to the copper salt creates a soluble, stable, and more active copper catalyst species in situ, which in turn improves the turnover rate of the reaction and lowers the activation barrier, in comparison to the classical Ullmann-type catalysis. Though only a catalytic amount of copper is needed, a stoichiometric amount of 1,10-phenanthroline (relative to aryl halide) is required to provide efficient catalysis. [Pg.187]

In another study, these workers found that cis complexes of palladium acetate with bidentate ligands such as o-phenanthroline will catalyze the exchange at higher temperatures (190). As trans complexes were inactive, it is likely that two adjacent cis coordination positions are required for catalysis. These new catalysts are extremely interesting and deserve further mechanistic study. [Pg.413]


See other pages where 1.10- Phenanthroline catalysis is mentioned: [Pg.76]    [Pg.468]    [Pg.359]    [Pg.384]    [Pg.653]    [Pg.656]    [Pg.558]    [Pg.1239]    [Pg.21]    [Pg.70]    [Pg.441]    [Pg.1018]    [Pg.175]    [Pg.73]    [Pg.341]    [Pg.306]    [Pg.157]    [Pg.509]    [Pg.468]    [Pg.441]    [Pg.1018]   
See also in sourсe #XX -- [ Pg.243 ]




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1 : 10-Phenanthroline

1 : 10-phenanthrolin

1.10- Phenanthroline, 2-cyanohydrolysis metal catalysis

Asymmetric catalysis, 1,10-phenanthroline

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