Dendritic zirconium

In the case of the bis-dendritic zirconium complex 91, a much smaller decrease in activity was observed relative to the reference zirconium complex, probably because of the bigger size of zirconium. Titanium dendrimers 88—90 gave polymers of higher molecular weights than those produced with CpTiCls. The polydispersity... 

The appearance of the deposit is as shown in Fig. 7.4 and consists of a grey mass of loosely adhering dendritic zirconium metal powder, firmly bormd to the steel rod by means of molten salts. 

A number of attempts to produce tire refractory metals, such as titanium and zirconium, by molten chloride electrolysis have not met widr success with two exceptions. The electrolysis of caesium salts such as Cs2ZrCl6 and CsTaCle, and of the fluorides Na2ZrF6 and NaTaFg have produced satisfactoty products on the laboratory scale (Flengas and Pint, 1969) but other systems have produced merely metallic dusts aird dendritic deposits. These observations suggest tlrat, as in tire case of metal deposition from aqueous electrolytes, e.g. Ag from Ag(CN)/ instead of from AgNOj, tire formation of stable metal complexes in tire liquid electrolyte is the key to success. 

We have prepared a variety of metalladendrimers from the reaction of phosphorus-containing dendrimers with various transition metal complexes. Dendritic complexes incorporating metals such as gold [28a, 57], iron [57,58,59], tungsten [58,59], rhodium [59, 60], platinum [60], palladium [61], ruthenium [62], or zirconium [63] were prepared. 

Various metal borides can be prepared by molten salt electrolysis. Frazer et al. (1975) have deposited ZrB on nickel cathode from ZrO and B Oj dissolved in molten NajAlF at 1020°C. A graphite crucible was used as anode. A series of nickel boride diffusion compounds were also noticed by electron microprobe analysis. The ZrB deposit was found to be scaly or dendritic and was usually non-adherent. Devyatkin (2001) has also obtained ZrB on nickel cathode from cryolite- alumina melts containing zirconium and boron oxide. 

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