Zirconium to Zinc

Non-racemic ligands screened in 1,2-additions of vinyl zirconocenes to aldehydes. 

Homoallylic amine formation resulting from a change in the mode of addition of reagents. 

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Before adding aldehyde 14 a transmetalation from zirconium to zinc is necessary because of low reactivity of the sterically hindered organozirconocene compounds like 18 toward most organic electrophiles.9 Resulting alkenylethylzinc 19 reacts in a 1,2-addition with the cr,y3-unsaturated aldehyde 14 transferring exclusively the alkenyl moiety. The formation of Z -allylic alcohol 20 reveals stereochemical retention of the double bond configuration in the transmetalation and addition steps. 

ALLYLIC ALCOHOLS BY ALKENE TRANSFER FROM ZIRCONIUM TO ZINC 1-[(tert-BUTYL-DIPHENYLSILYL)OXY]-... 

Wipf, P. Xu, W. Allylic Alcohols by Alkene Transfer from Zirconium to Zinc l-[(rert-Butyldiphenylsilyl)oxy]-dec-3-en-5-ol OS, (1996), 74,205. 

A wide array of ferroelectric, piezoelectric and pyroelectric materials have titanium, zirconium and zinc metal cations as part of their elemental composition Many electrical materials based on titanium oxide (titanates) and zirconium oxide (zirconates) are known to have structures based on perovskite-type oxide lattices Barium titanate, BaTiOs and a diverse compositional range of PZT materials (lead zirconate titanates, Pb Zr Tij-yOs) and PLZT materials (lead lanthanum zirconate titanates, PbxLai-xZryTii-yOs) are among these perovskite-type electrical materials. 

Just as silicon in the first group shows similarities with titanium on the one hand and with germanium on the other, there exists in exactly the same way a relationship between the elements of the 2nd and 3rd groups, for example from zirconium to cerium with an atomic weight of 140 on the one hand and from zirconium to an unknown element with an atomic weight aroimd 181 on the other. There are a large number of rare-earth elements in between these two elements which are related to one another like the central elements of the 3rd series placed between manganese and zinc. (Thomsen, 1895 Trifonov, 1966). 

True vein deposits of uranium are not very common except perhaps in Europe. Uranium in such deposits commonly occurs with. . minerals, such as tin, copper, cobalt, vanadium and arsenic. .. (Bowie, 1972, p. 3). In Europe, as in the U.S.A. (Walker and Osterwald, 1963), the assemblage commonly includes pyrite and other sulfide minerals. Moreover, there is an association of metals in veins which is significant. Walker and Adams (1963, pp. 76—77) state The positive correlation of certain metals — notably molybdenum, manganese, beryllium, tungsten, vanadium, niobium, yttrium, and zirconium — to uranium in veins seems to be reasonably well-established within some deposits, districts, or restricted geographic areas, but none of these metals can be shown to correlate with uranium in all or even a large percentage of vein deposits. In addition to the metals that, when present, appear to correlate intimately with uranium, many other metals such as lead, zinc, copper, silver, and cobalt are associated with uranium in many... 

This study compares the effect of catalysts on aliphatic and aromatic isocyanates. With the exception of di-n-butyltin dithiocarbonate, all the di-n-butyltin catalysts perform similarly. The DABCO catalyst shows excellent catalysis for aromatic isocyanates and is less effective for aliphatic isocyanates. Combining this amine catalyst with DBTDL gives excellent catalytic activity for both aliphatic and aromatic isocyanates. Stannous, zirconium, and zinc octanoate show reduced activity in comparison to organotin. 

Exchange of the zirconium for zinc allows addition to carbonyl compounds. A free alcohol group, as in 130, must be protected and the zirconium in the initial product 132 replaced by zinc before the aldehyde is added to give the allylic alcohol 134. Both reactions occur with retention of configuration.29... 

In addition to the elements discussed above, there have been claims in the literature for the framework incorporation of other elements, viz germanium (145,169), chromium, copper, zirconium, and zinc. However, except for germanium, the incorporation of the metals into the framework is viewed criticaUy by the authors. To the best of our knowledge, none of these materials have found commercial application, and they are not reviewed further. 

In fact, the classification of chemical elements is valuable only in so far as it illustrates chemical behaviour, and it is conventional to use the term transition elements in a mote restricted sense. The elements in the irmer transition series from cerium (58) to lutetium (71) are called the lanthanoids those in the series from thorium (90) to lawrencium (103) are the actl-noids. These two series together make up the /block in the periodic table. It is also common to include scandium, yttrium, and lanthanum with the lanthanoids (because of chemical similarity) and to include actinium with the actinoids. Of the remaining transition elements, it is usual to speak of three main transition series from titanium to copper from zirconium to silver and from hafnium to gold. All these elements have similar chemical properties that result from the presence of unfilled d-orbltals in the element or (in the case of copper, silver, and gold) in the ions. The elements from 104 to 109 and the undiscovered elements 110 and 111 make up a fourth transition series. The elements zinc, cadmium, and mercury have filled d-orbltals both in the elements and in compounds, and are usually regarded as nontransition elements forming group 12 of the periodic table. 

Metallergical industries (85%), primarily stainless steel. It is added to harden the metal and provide high-temperature strength and corrosion resistance. It is also used in combination with aluminium, zirconium, and zinc alloys. 

Transmetallation of the organic group from zirconium to another metal opens up possibilities. The palladium-catalysed coupling reactions can be found in Section 2.4. Addition of dimethyl cuprate results In transmetallation to copper. The resulting cuprate then displays typical cuprate reactivity, such as addition to enones. More economically, small amounts of copper can catalytically activate the zirconium complex towards this kind of chemistry, although the precise mechanism is unclear. Additions to enones can also be achieved directly using nickel catalysis (Scheme 5.64). Transmetallation to zinc has also been demonstrated. ... 

Negishi and his co-workers have developed several approaches to allylated arenes involving cross-coupling reactions. Preliminary studies established that aryl-aluminium, zirconium, or zinc compounds readily undergo palladium-catalysed cross-coupling with allylic halides or acetates (Scheme 19). Later in the year it was shown that allylic alcohol derivatives containing OAlR2,... 

The manufacturing industry is emphasizing quality, efficiency, and environmental compatibility. Zirconium is well positioned to meet these needs. Interest in zirconium and its chemicals is on the rise. However, there is still a persistent perception that zirconium is exotic and costly. Actually, zirconium is plentiful. In the earth s crust, zirconium is more abimdant than many common elements, such as nickel, copper, chromium, zinc, lead, and cobalt. The prices of zirconium and its alloys have been relatively stable for many years. They are very competitive with other high-performance materials. Life cycles costs of zirconium equipment can be particularly attractive. There is much room for zirconium to grow in the coming years. 

Reactor-grade zirconium is essentially free of hafnium. Zircaloy(R) is an important alloy developed specifically for nuclear applications. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis, by sea water, and by other agents. Alloyed with zinc, zirconium becomes magnetic at temperatures below 35oK. 

AHoy M16630 (ZE63A) which contains rare-earth metals and zinc, is designed to take advantage of a newer he at-treatment technique involving inward diffusion of hydrogen and formation of zirconium hydride [7704-99-6]. The alloy is heated in hydrogen at 480°C for 10, 24, or 72 hours for 6.3,... 

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