Controlled/living polymerizations. A. Synthesis of block copolymers with bicyclic acetals by cationic ring opening polymerization. B. Synthesis and study of tetradentate ligands coordinated to copper(I) and copper(II) for use as ATRP catalysts.

摘要

Cationic ring opening polymerization (CROP) has been used to polymerize bicyclic acetals, such as 6,8-DBO, in a controlled fashion. Triblock copolymers containing 6,8-DBO and PEG have been synthesized by this method. The desired triblock copolymer was achieved via a difunctional macroinitiator of PEG. The best Lewis acid activator was also explored, ZnCl₂ and ZnI ₂.; The key component that governs the chemistry of ATRP is the copper (I) catalyst, yet not much is understood about their solution chemistry and the mechanisms by which they affect atom transfer. In order to better understand these systems, we have developed a library of tetradentate ligands to study, (2,6-diisoproylphenyl)-3-(bis-2-pyridylmethyl) aminopropanamide (DPPMAP), N-(2,6-diisopropylphenyl)-3-(bis-2-pyridytmethyl)aminoethanamide (DPPMAE), octyl-3-(bis-2-pyridalmethyl)amino ethanamide (OMAE), tert-butyl-3-(bis-2-pyridalmethyl)amino ethanamide (tBMAE), N-(2-(bis-2-pyridylethyl)amino)ethyl benzamide (PEABA) and N-(2-hydroxyphenyl) methyl-bis(2-pyridytmethyl)amine (ABBA). Each ligand contains a monoanionic site, either an amide or a phenyl group that can be deprotonated. The course of study for these ligands, includes synthesizing and characterizing them, then complexing them with both CuICl and CuIIBr₂ and characterizing them. The resulting complexes were subsequently deprotonated either with KOtBu or NaH, both CuI and CuII. The resulting [DPPMAP]Cu I complex was the reacted with an ATRP initiator and TEMPO to isolate the activation step of ATRP. This reaction was monitor by UV-vis, GC-MS and NMR. [DPPMAP]CuI was also used in a series of polymerizations, all of which were redox-initiated, not ATRP. The [DPPMAP]CuI was also oxidized by CBr₄, and the [DPPMAP]CuIIBr ₂ was deprotonated. The two resulting products were compared via EPR, to determine if the two were the same product.