NMR Investigation of Tetrad Splitting in Regularly Alternating Diphenylene Oxide–Diphenylene Sulfide Copolyarylenephthalides of Periodic Structure

Tetrad splitting of the quaternary sp³-hybridized carbon atom in a series of model (co)poly-arylenephthalides differing in the length of the phenyleneoxyphthalide (O) and phenylenethiophthalide (S) sequences: O-1, OOOS-2, OOS-3, OS-4, SSO-5, SSSO-6, S-7, and OOSS-8 has been studied using the increments method. Basing on the analysis of the amplitude values of the dyad increments, the tetrad increments have been calculated and the position of the signals of the tetrads in the ¹³С NMR spectra of the individual (co)polyarylenephthalides and their mixtures has been predicted. Validity of the calculations has been confirmed by the coincidence between the predicted and the experimental values of the dyad and tetrad increments for the specifically synthesized (co)polyarylenephthalide OOSS-8, the spectra of the mixtures of the (co)polyarylenephthalides with equimolar content of the split tetrads, and good coincidence of their starting compositions calculated from the deconvoluted spectra.