Phosphoranimines, examples

In addition to providing fully alkyl/aryl-substituted polyphosphasenes, the versatility of the process in Figure 2 has allowed the preparation of various functionalized polymers and copolymers. Thus the monomer (10) can be derivatized via deprotonation—substitution, when a P-methyl (or P—CH2—) group is present, to provide new phosphoranimines some of which, in turn, serve as precursors to new polymers (64). In the same vein, polymers containing a P—CH group, for example, poly(methylphenylphosphazene), can also be derivatized by deprotonation—substitution reactions without chain scission. This has produced a number of functionalized polymers (64,71—73), including water-soluble carboxylate salts (11), as well as graft copolymers with styrene (74) and with dimethylsiloxane (12) (75). 

As can be seen, the first example of phosphoranimine polymerization process was proposed by E. P. Flindt and H. Rose [314] in 1977 for tris(trifluoroethoxy)-AT-(trimethylsilyl)phosphoranimine, which could be polymerized to poly[bis-(trifiuoroethoxy)phosphazene] (MW 4000-10,000) by simple heating at 200 °C. 

The possibility of incorporating unsaturated groups into the polymers, as potential sites for crosslinking, is also being explored. For example, the vinyl (7, 8), ally (9), and butenyl (10) substituted phosphoranimines have been prepared and subjected to the usual thermolysis and cothermolysis conditions (eq 3). In these cases, all of which have a terminal... 

Several synthetic pathways exist for the direct preparation of poly(organophosphazenes) that are based on the polymerization of phosphoranimines that already bear organic side groups. For example, various poly(organophosphazenes) are accessible via the polymerization of Me3Si-N= PR2(0CH2CF3) as shown in reaction and oth-... 

This S5mthetic method has been extended to the direct synthesis of poly(organophosphazenes) as well as the development of star and block copolymers. For example, triarmed star-branched polyphosphazenes (eg, 6) can be synthesized through the initiation of trifimctional phosphoranimines (22). It has also been shown that the presence of living active sites at the termini of the poljuner chains allows for addition of a second monomer and the formation of block copolymers (23), such as (7) which is formed through the initiation of a difunctional linear phosphoranimine and the subsequent introduction of two different monomers (24). These developments offer the prospect of improved routes... 

Phosphoranimines, which are of interest as monomers in phosphazene polymer synthesis, may be isolated as cationic structures stabilized by donor ligands. In this example, a chlorinated phosphoranimine carrying a hindered aromatic substituent reacts with N,N-dimethylaminopyridine (DMAP) to yield a donor complex. Scheme 4. The donor complex structure was proposed based on single crystal x-ray analysis that revealed a... 

Only a few other examples of N-phosphoryl-phosphoranimines have been previously reported. Most notable of these is the perchloro analog which has been shown to be an effective precursor to poly(dichlorophosphazene) via the thermal elimination of P(0)Cl3 (equation 1). (7) In contrast, our phosphoryl derivatives, which contain various substituents at the P=N phosphorus center other than chlorine, do not decompose in the same manner. Instead, we find that the only significant volatile products are phosphine oxides (fi-om the phenoxy compounds) or, more surprisingly, CF3CH2CI (form the trifiuoroethoxy analogs). These products probably result firom the types of firagmentations indicated in Scheme 7. The non-volatile, possibly oligomeric, products of this decomposition process are not readily... 

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