Chromium Azide

Chromium Azide Complexes In attempting to prepare Cr azide from a soln of CrfNOsX and NaNj in pyridine, Oliveri-Mandala (Ref 5)... 

Aq sol ns of sodium chromium azide did not react with Cr or N3 but with AgNOt gave an expl complex salt. The sodium chromium azide is considered to be the Na salt of chromihy-drazoic acid, HsCr(N3)6, but this acid was not isolated because it decomposed too readily. Attempts to obtain it by the methods of Wohler Martin (Ref 4) failed... 

Strecker Schwinn (Ref 8) prepd the following chromium azide comrde t salt ... 

The kinetics of aquation of a number of azidochromium(III) complexes have been investigated.303,655 Compared with other acidochromium(III) complexes, the chromium-azide bonds in these species seem remarkably stable to thermal substitution. Hence in the base hydrolysis of [CrN3(NH3)s]2+ a pathway involving initial loss of NH3 concurs with the usual base hydrolysis pathway involving loss of Nj. The aquation of azidochromium(III) complexes is H+-assisted with protonation of the azido ligand accounting for the enhanced reactivity. 

Chromic Azide Complexes. See Chromium Azide Complexes in Vol 1, pA530-R and also Azidopentammine-chromium (III) Perchlorate, Chloropentamminechromium (III) Azide and Hexamminechromium Azide on pA277 under Ammines... 

Chloronitroanilinopropanols A436-R Chromium Azide A530-L Chromium Azide Complexes A530-R Chromium Carbide. See under Acetylides and Carbides A72-R... 

Jacobsen and co-workers have used similar catalysts in the enantioselective opening of epoxide rings. Stereospecific hydrolysis with a cobalt acetate chelate can be used to resolve racemic epoxides.97 Propylene oxide was opened with trimethylsilylazide in the presence of a 7 7 chromium azide chelate catalyst to produce (5)-l-azido-2-trimethyl-siloxypropane in quantitative yield with 97% ee.98 Cyclohexene oxide was opened with benzoic acid in the presence of 1 mol% cobalt chelate catalyst to give the hydroxyben-zoate in 98% yield with 77% ee.99... 

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