Synthesis and Refractive-Index Properties of Star-Shaped Polysulfides Radiating from Calixarenes

The continuous insertion reaction of phenoxypropylenesulfide (PPS) into the thioester moieties of calixarene derivatives (cores) generated from p-tert-butylthiacalix[4] arene (BTC[4]), 2,9,14,20-tetramethylclix-[4] resorcinarene (CRA[4]), and 2,8,14,20-tetra(4-hydroxybenzen-1-yl)calix[4]resorcinarene {CRA(Ar-OH)[4]} proceeded smoothly with tetrabutylammonium chloride (TBAC) as a catalyst to give well-defined star-shaped polysulfides with 4. 9 and 12 arms, The arm length and Sulfur content of the star-shaped polysulfides were controlled by the feed ratio of PPS and core. The refractive-index values (n(D)'s) of the synthesized star-shaped polysulfides were determined in the film state by means of ellipsometry; the n(D)'s increased with increasing numbers of arms, length of arms, and sulfur content and with decreasing size of the core structure.