Aluminum-zirconium organic metal

An aluminum-zirconium organic metal complex coupling agent with the brand name of Cavedon Mod is one new type of coupling agent developed by American Cavedon chemical companies in the early 1980s. It was synthesized from zirconium oxychloride, chlorohydrin aluminum hydrate, propylene glycol, carboxylic acid, and so forth. Its molecular structure is shown below. 

Hydrozirconation of alkenes. This organic metallic reagent reacts with olefins at 25-40° to form alkylzirconium complexes of the type (C5115)2 Zn(R)Cl, in which the transition metal moiety is attached to the least hindered position of the olefin. For example, when a suspension of (1) in benzene is shaken with 1-octene or either cis- or tran -4-octene, (2) is formed in quantitative yield. Thus internally metalated zirconium compounds undergo rearrangement much more rapidly than organoboron or aluminum analogs. Other examples of hydrozircon-ation are formulated. Very hindered olefins e.g., tetramethylethylene) fail to react at 40°. 

Protons are released upon heating which in part balance the negative charge of the host clay layers. A number of review articles have recently appeared which summarize the synthesis and physical properties of metal oxide pillared days derived fix>m the intercalation of polyoxocations of aluminum, zirconium, chromium and many other metals [10-12]. The Lewis acid sites provided by coordinatively unsaturated metal ion sites on the pillar and the Bronsted addity formed upon thermolysis imparts novel chemical catalytic properties [13,14]. Since the pores between pillars often are larger than those foimd in conventional zeolites, there is considerable interest in the use of metal oxide pillared clays for the processing of large organic molecules, espedally petroleum [14-17]. 

Vol. 3 Photometric Determination of Traces of Metals. Fourth Edition Part I General Aspects. By E. B. Sandell and Hiroshi Onishi Part IIA Individual Metals, Aluminum to Lithium. By Hiroshi Onishi Part IIB Individual Metals, Magnesium to Zirconium. By Hiroshi Onishi Vol. 4 Organic Reagents Used in Gravimetric and Volumetric Analysis. By John F. Flagg (out ofprint)... 

Concomitant with continued olefin insertion into the metal-carbon bond of the titanium-aluminum complex, alkyl exchange and hydrogen-transfer reactions are observed. Whereas the normal reduction mechanism for transition-metal-organic complexes is initiated by release of olefins with formation of hydride followed by hydride transfer (184, 185) to an alkyl group, in the case of some titanium and zirconium compounds a reverse reaction takes place. By the release of ethane, a dimetalloalkane is formed. In a second step, ethylene from the dimetalloalkane is evolved, and two reduced metal atoms remain (119). 

Carr, D. B., Schwartz, J. Transmetalation preparation of organometallic reagents for organic synthesis by transfer of organic groups from one metal to another. Transmetalation from zirconium to aluminum. J. Am. Chem. Soc. 1977, 99, 638-640. 

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