1.3- Diimines oxygenation

The requirement of hydrogen peroxide or oxygen in diazaquinone chemiluminescence appears to be another argument against the hypothesis of Albrecht 128> or of Kautsky and coworkers 132> that the diazaquinone is simply hydrolyzed to yield aminophthalate and diimine which in turn reduces other diazaquinone molecules to luminol in an excited state so that it then emits. 

One very fast and reliable method for the reduction of double bonds is that of transfer hydrogenation with diimine (Scheme 20.30). Under the influence of traces of copper ion and oxygen from air, hydrazine is rapidly transformed into diimine. This compound is able to hydrogenate double bonds with great success under the formation of nitrogen [120],... 

For the replacement of oxygen by hydrogen in ketones and aldehydes the method of Kishner and Wolff is used as often as is that of Clemmensen. In the former method the hydrazone or semicarbazone of the carbonyl compound is heated for several hours—preferably in the presence of hydrazine hydrate—in a sealed tube or autoclave with sodium ethoxide at about 160°. The explanation of the reaction is that, under the catalytic influence of the ethoxide, the hydrazone is transformed into a diimine which then decomposes in the same way as does phenyldiimine (p. 286) ... 

The ferrocene-linked bis-bipy and bis-phen ligands (181) and (182) form very stable iron(II) complexes in which the ligands are bonded to the metal through two carbonyl oxygens in addition to the two diimine groups." ... 

The oxygenation of the fi-diimine complex to give compound (66) (Scheme 71) could be a more general process as both the diheteroarylmethanes (69) and (70) undergo metal-catalyzed oxygenation to the related products (71) and (72) respectively.225-226... 

Bis(salicylaldehyde)diimine complexes of cobalt take up and release molecular oxygen with such efficiency that they have been made use of for the purification of oxygen.66... 

Aza-analogues of oxygen compounds frequently show related reactivity patterns, and this is certainly seen in a comparison of the chemistry of imines and carbonyl compounds. For example, 1,3-diimines are readily deprotonated to yield the 1,3-diketonate analogues. The most frequent consequence of this is that reactions which are expected to yield 1,3-diimine complexes often lead to those of the deprotonated species. This is seen in the formation of the gold(m) complex of a deprotonated macrocycle in the reaction of 1,2-diaminoethane with 2,4-pentanedione in the presence of Na[AuCl4] (Fig. 5-4). The exact sequence of events in this reaction is not known, but note that the product is a square-planar gold(in) complex of the doubly-deprotonated macrocycle, rather than a gold(i) species ... 

Figure 9-37. The oxidation of an iron(n) diimine complex with cerium(iv) results in an oxygen atom transfer to give a complex of the hydroxyimine tautomer of amide 9.22,...

Figure 4-26. Unconstrained MD simulations for methyl acrylate bound to the palladium/nickel diimine complex through the oxygen (top-right/bottom-right) and the C=C (top-left/bottom-left) functionalities. The three panels in each of the four graphs represent variations in the metal-carbon (top two panels) and metal-oxygen (bottom panel) distances. The simulations were carried out at 300 K for all the systems, and 700 K for the local minima, as indicated...

Figure 4-27. Changes in the two distances between the olefin carbons and the metal (M — C(ir) and M — C tt)) as well as the metal-oxygen distance M-O from constrained MD and die following relaxation (unconstrained) simulations for the methyl acrylate ir-complex — > a-complex interconversion with the Ni-based diimine catalyst. The initial and finalgeometries are shown in the figure...

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