|121. Schmitt, B.; Schlaad, H.; Müller, A.H.E.; Mathiasch, B.; Steiger, S.; Weiss, H.: Anionic Polymeritation of (Meth)acrylates in the Presence of Tetraalkylammonium Halide Trialkyl Aluminum Complexes in Toluene, 2. NMR and Quantum-chemical Study on the Structure of Ester Enolate Complexes as Models of the Active Center, Macromolecules 33, 2887 (2000)|
6Li and 13C NMR investigations on ethyl -lithioisobutyrate (EiBLi) and quantum-chemical (DFT) calculations on methyl -lithioisobutyrate (MiBLi) were performed to study the structure of active centers in anionic polymerization of methacrylates in toluene in the presence of tetramethylammonium chloride/triethylaluminum complexes NMe4[AlnEt3nCl] (n = 1, 2). The results support the existence of several complex species ([EiBLi·AlnEt3nCl]NMe4)m varying in composition (n = 1, 2) and degree of association (m = 1, 2). In the presence of methyl pivalate (MPiv), a model compound for monomer/polymer ester groups, a nonassociated complex NMe4[EiBLi·MPiv·AlEt3Cl] is preferably formed.