Exchange reactions, metathetical

R = CeHsPr 2-2,6 (ref. 180a) C6H4Ph-2 (ref. 180b) C6H3Bu 2-2,5 (ref. 180b) 

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Attempts to prepare Ta(NEt2)5 by metathetic exchange reactions were found to lead to a complex in which activation of a )3-CH bond of an NEt2 ligand occurs with the elimination of diethylamine (equation 92), 244 345 Presumably steric pressure at the tantalum center promotes the cyclometallation reaction to generate the iminomethyl group. 

New sulphinato-complexes of AgfCu, Au) have been prepared by the metathetical exchange reaction (46).205 The Ag and Cu complexes were shown by i.r. studies to... 

Other inorganic metathetical exchange reactions studied include the replacement of bromine by fluorine and chlorine in N3P3Br6 and the preparation of azido-, cyano-, and isothiocyanatocyclophospha-zenes (21, 22, 249). In the reactions of N3P3C16 with KF and KSCN, addition of [18-Crown-6]ether considerably enhances the yields of substituted cyclophosphazenes, N3P3R6 (R = F, NCS) (449). 

A much more widely used synthetic method entails the metathetical exchange reaction between alkali metal aryloxides and the metal halide. This procedure has been applied to the synthesis of lanthanide, actinide, and d-block metal aryloxides as well as derivatives of the main group metals (Eqs 6.23, 6.24, ° 6.25, " 6.26, 6.27, 6.28, 6.29, and 6.30 ° ). 

A polymer chain is created either by an addition reaction to a double bond, via a condensation reaction, or by a metathetical (exchange) reaction. In all cases the final structure is a long chain, which has a high molar mass. In the case of synthetic polymers the chain will be formed by repeating the simple building block — a monomer — many times. The term polymer reflects the structure of the molecule po/y indicating that it involves many of the mono-wer units. 

As stated earlier, the interaction between tetraalkyltin and Re207 supported on Si02-Al203 or alumina gives rise to a rhenium alkyUdene species. In order to verify whether an alkylidene ligand could be formed via a metathetical exchange reaction, the catalysts promoted with Et4M (M=Sn, Ge, or Si) were allowed to... 

The salts, [PPN]n[M(CN)6] (M = Fe, n = 3 or 4 M = Ru, n = 4 M = Co, n = 3) and [PPN][Fe(CN)5(NO)], have been prepared by metathetical exchange reactions in aqueous solution between [PPN]C1 and the corresponding alkali metal salts of the cyanometallates7 Unlike alkali metal salts, the [PPN]+ salts are very soluble in chlorinated solvents and in most polar, aprotic solvents including acetonitrile, acetone, and dimethyl sulfoxide. 

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