A General Protocol for the Polycondensation of Thienyl N‑Methyliminodiacetic Acid Boronate Esters To Form High Molecular Weight Copolymers

摘要

Thienyl di-MIDA boronate esters are readily synthesizedby electrophilic C-H borylation producing bench stable crystallinesolids in good yield and excellent purity. Optimal conditionsfor the slow release of the boronic acid using KOH as the base inbiphasic THF/water mixtures enables the thienyl MIDA boronateesters to be extremely effective homo-bifunctionalized (AA-type)monomers in Suzuki-Miyaura co-polymerizations with dibromoheteroarenes(BB-type monomers). A single polymerization protocolis applicable for the formation of five alternating thienyl copolymersthat are (or are close analogues of) state of the art materialsused in organic electronics. The five polymers were produced inexcellent yields and with high molecular weights comparable tothose produced using Stille co-polymerization protocols. Thereforethienyl di-MIDA boronate esters represent bench stable / low toxicityalternatives to highly toxic di-trimethylstannyl AA-type monomersthat are currently ubiquitous in the synthesis of these importantalternating copolymers.