Synthesis of aliphatic polymers with high refractive index by photoinduced polyaddition of thiols to bifunctional allyl monomer containing tetrathiaspiro structure

Abstract

Zinc chloride effectively catalyzed the reaction of allyl-substituted episulfide and cyclic trithiocarbonate to obtain the corresponding bisallyl monomer containing tetrathiaspiro ring in high yield. The homogeneous mixture of the bisallyl monomer, multifunctional thiols, and a catalytic amount of photo-radical initiator undergoes a photoinduced thiol–ene reaction to result in cross-linked films. Thus the films obtained in this way, although they are aliphatic polymers containing neither aromatic ring nor halogen atom, have a high refractive index (nD25) of around 1.63. Figure S1. UV spectra of 2 and M1 in CH3CN (10 mg/L, respectively). Table S1. Refractive indices of P1 and P2 at different wavelengths. Figure S2.1H NMR spectrum (400 MHz) of a solution of M1 in CDCl3 at 25 °C. Figure S3.13C NMR spectrum (100 MHz) of a solution of M1 in CDCl3 at 25 °C. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.