Tungsten reaction with oximes

We found [44, 46, 47] that the course of the reactions of WOF4 (M0OF4) with oximes is similar to that found for secondary amines and ketimines. These data and the findings reported in [45] make it possible to present the reaction of simple oximes with tungsten or molybdenum oxotetrafluorides by the overall equation... 

In the class of hydrazones, the properties of molecules are primarily determined by the behavior of the atomic triad N-N=C. In reactions with tungsten halides, these compounds behave similarly to hydrazines and simple oximes. 

Irradiation (with a tungsten lamp) of the oximes (154) under oxidative conditions (PhI(OAc)2-l2 in dichloromethane) yields the adduct (155). The reaction can also be brought about using HgO-Ii and irradiation with a medium pressure Hg arc lamp. The formation of the naphthisoxazoles (155) can be interpreted as the addition of a nitrile oxide to an aryl ring. Such a 1,3-addition is unprecedented under such conditions. 

The group of potential 0,N-two-center ligands includes oximes (>C=N-OH), as well as hydroxylamine NH2OH, and its derivatives. The iri -coordination of simple oximes and substituted hydroxylamines in d transition metal complexes was reported almost simultaneously in Russia [9] and elsewhere [42,43]. More speciflcally, it was found [9,44,45] that the flnal product of the reaction between tungsten (molybdenum) oxotetrafluoride and simple oximes and p-phenylhydroxylamine is a complex anion with the deprotonated organic ligand [M0F4L] (where M=Mo, W HL stands for acetoxime, acetaldoxime, benzal-doxime, 2- and 4-pyridinaldoxime, and p-phenylhydroxylamine). 

Spec A = 665 nm of the titanium-methylene blue-ascorbic acid redox reaction Spec A= 420 nm of the yellow Tiron derivative (pH = 5.2 to 5.6) Spectrophotometric determination of tungsten with thiocyanate after both tungsten(VI) and molybdenum(VI) are extracted into chloroform as benzoin a-oxime complexes... 

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