Tetraphenylsilane-containing polyarylates with well-defined functional groups via postpolymerization modification

New tetraphenylsilane-containing polyarylate with two pendant benzyl ester groups was synthesized successfully by direct polycondensation from a new silicon-containing aromatic diacid monomer bis[p-(benzyloxycarbonyl)phenyl]-bis(p-carboxyphenyl)silane (BBCS) with p-dihydroxybenzene in pyridine, using dimethylformamide as the activator and p-tosyl chloride as the condensing agent. Then, the benzyl ester groups were smoothly converted to carboxyl groups by catalytic hydrogenation, obtaining the polyarylate with two carboxyl groups attached on the phenylenes of tetraphenylsilane moiety. The new monomer and polyarylates were characterized by 1H NMR, FTIR, wide angle X-ray diffraction and gel permeation chromatography methods. The carboxyl-containing polyarylate exhibited good solubility in most polar aprotic solvents and had the 5% weight loss over 400 °C. The presence of well-defined carboxyl groups and rigid tetrahedral structure of tetraphenylsilane in the polyarylate provides the feasible routes to the preparation of either hypercrosslinked covalent organic framework materials or optoelectronic materials through the reaction with chromophoric compounds.