Ga. Carriedo et al., Spectroscopic and solution properties of phenoxyphosphazene random copolymers containing optically active binaphthoxy groups, MACROMOLEC, 33(10), 2000, pp. 3671-3679
The reaction of a mixture of [NPCl2](n) and Cs2CO3 first with (R)-(+)-1,1'-
binaphthyl-2,2'-diol (HO-C10H6-C10H6-OH) (binaphthol) and subsequently with
phenol (HO-C6H5) in refluxing 1,4-dioxane gave the series of the optically
active random copolymers {[NP(O2C20H12)](x)[NP(OC6H5)(2)](1-x)}(n) (2). Ab
solute molecular weight distributions and radius of gyration have been dete
rmined by size exclusion chromatography, using simultaneously multiangle li
ght scattering and differential refractive index detectors. The dependence
of the dimensions of the polymers on the molecular weight through the corre
sponding scaling laws is studied. In addition, a stereochemical study of ho
mopolymers [NP(O2C20H12)](n), I and copolymers 2 based on the CD exciton ch
irality method is also included. The reaction of the partially substituted
polymer [NP(R-O2C20H12)(0.4)(Cl-2)(0.6)](n) with the stoichiometric amount
of racemic binaphthol, or with a large excess of the latter, in the presenc
e of Cs2CO3 gave the same polymer [NP(R-O2C20H12)(0.4)- (rac-O2C20H12)(0.4)
](n) [(-)-3] irrespective of the amount of racemic binaphthol used, showing
no enantiomeric induction by the R-binaphthoxy units already present in th
e polymer.