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This paper examines the modification of zeolites with superstoichiometric amounts of metals using multistep cluster synthesis. Ion-exchange sites in zeolite MFI-50 (SiO2/Al2O3 molar ratio of 50) have been modified with hydrazonium cations. Subsequent redox reaction with chromate anions has yielded a chromium-containing zeolite. The sample prepared by three ion-exchange/redox cycles contains 10 wt % chromium (Cr-MFI-50). EPR results show that most of the chromium in Cr-MFI-50 is in the form of fine Cr2O3 particles. In addition, the material contains isolated Cr5+ ions and, presumably, Cr3+ stabilized at aluminum vacancies.

A general approach has been proposed for incorporating high concentrations of modifier metals into high-silica zeolites. MFI zeolites have been modified with mono- and polymetallic sulfide clusters of copper, manganese, zinc, cobalt, and nickel. The metal incorporation sequence and the nature of the anion have been shown to influence both the total content and the ratio of the modifiers in the zeolite. Using multistep syntheses, we have prepared zeolites containing superstoichiometric amounts of modifier metals. Using a variety of physicochemical characterization techniques, the zinc-containing sample has been shown to have a uniform modifier distribution. The Cu-MFI-50 and Mn-MFI-50 zeolites have been characterized by electron paramagnetic resonance and shown to contain isolated Cu2+ and Mn2+ ions stabilized on the aluminum lattice site.

Unusual cascade cycloaddition reactions with dimethylhydrazones of α-trimethylsilyloxyalkylacroleins acting as azadienes were found. Depending on the nature of the dienophile, the reactions give either fused heterocyclic compounds (when two consecutive Diels—Alder reactions take place) or azabicyclic compounds, resulting from the [2+4]- and [2+3]-cycloaddition cascade.

The method for the preparation of α-substituted acrylonitrile derivatives by the quaternization of the nitrogen atom of both Me2N groups in the corresponding substituted 3-(dimethylamino)propanal dimethylhydrazones followed by the Hoffman decomposition of the resulting diiodides was developed.

The method for the preparation of α-substituted acrylonitrile derivatives by the quaternization of the nitrogen atom of both Me2N groups in the corresponding substituted 3-(dimethylamino)propanal dimethylhydrazones followed by the Hoffman decomposition of the resulting diiodides was developed.

Unusual cascade cycloaddition reactions with dimethylhydrazones of α-trimethylsilyloxyalkylacroleins acting as azadienes were found. Depending on the nature of the dienophile, the reactions give either fused heterocyclic compounds (when two consecutive Diels—Alder reactions take place) or azabicyclic compounds, resulting from the [2+4]- and [2+3]-cycloaddition cascade.