Zirconium-carbon-nitrogen system

Intramolecular addition of amine N-H bonds to carbon-carbon multiple bonds would afford nitrogen heterocycles. To realize catalytic cyclization of a,co-aminoalkenes or aminoalkynes, various catalytic systems have been developed especially with early transition metals such as titanium, zirconium, lanthanide metals, and actinide metals [ 12], Late-transition-metal catalysis based on Ni, Pd, and Rh has also proved to be efficient [ 12], Recently, the ruthenium-catalyzed intramolecular hydroamination of aminoalkynes 15 was reported to afford 5-7-membered ring products 16 in various yields (Eq. 6) [13]. Among... 

With few exceptions there have been no studies of the effect of oxygen and nitrogen impurities on the Hf-C system. It is not unreasonable, however, to expect this system to behave like the other members of Group 4 in this regard. An additional difficulty is created by the frequent presence of zirconium, which generally depresses the various properties. When the zirconium content is given, the reported measurements have been corrected assuming the mixed system to have a linear variation of the property between end members of equal carbon content. 

Another catalyst system found in the patent literature involves the deposition of halides such as zirconium tetrachloride, vanadium tetrachloride, titanium tetraiodide, or oxyhalides such as chromium oxychloride or vanadium oxychloride on a finely divided particulate inorganic substrate having surface hydroxyl groups. Among such solids are alumina, zirconia, silica (particularly a pyrogenic silica such as Cab-O-SiF ), or a carbon black such as channel black or furnace black. A toluene slurry of this material is added, under dry nitrogen, to a toluene solution of A -vinyl-pyrrolidone containing a small amount of triisobutylaluminum. After 24 hr at 80°C, a 25% yield of polymer is produced [73]. 

Boron, carbon and nitrogen from this polymer can not only react with the zirconium to form solids but also with the release of oxygen and hydrogen. Thermal dynamic calculations were carried out for the pyrolysis of [Zr(acac)2(C4HgO)2] and ZrB precursor with a B/Zr molar ratio of 2. Solids formed in the systems... 

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