ROP of Substituted Cyclophosphazenes

Substituted chloro- and fluorocyclophosphazenes can also be polymerized to their high polymers by the ROP method. Several alkylcyclophos-phazenes such as N3P3CI5R, have been polymerized. These can be prepared from the corresponding hydridophosphazenes (see Eq. 3.48). 

Monosubstituted fluorocyclophosphazenes such as N3P3FsPh and N3P3F5tBu can be pol5anerized by ring-opening polymerization to the corresponding polymer (see Eq. 3.50). 

Some disubstituted cyclophosphazenes such as [ NPCl2 2 NP(R)(CH2SiMc3) ] have also been polymerized by the ringopening method to afford the linear polymers (see Eq. 3.51) [29]. 

When R = Bu or neoCsHu in the above ease (Eq. 3.51) the polymerization is retarded. Some other disubstituted derivatives that have been polymerized include ggm-N3P3Cl4(N=PCl3)2, non-gem- H-iV-iCX ti, non- 

In general, persubstituted cyclotriphosphazenes containing amino, alkoxy or aryloxy substituents cannot be polymerized by ROP. However, a few exceptions exist. 

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