Cyano cyclophosphazenes

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). 

In addition to classical substituents such as NH2, NHR, NR2, OR, SR in various combinations, in recent years some more exotic groups have been attached to phosphazene rings. Among the novel cyclic phosphazenes the carbo-rane substituted derivatives are worth mentioning. Other unusual derivatives include chiral cyclophosphazenes, cyano-, ferrocenylphenoxy-, and ferrocenylhydrazone-cyclophosphazenes. Another interesting development is the synthesis of crown ethers with chlorocyclophosphazene subunits (Scheme 54). ... 

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