The reactivity of n-butyllithium (n-BuLi) toward pyridine derivatives (pyridine, pyridazine, pyrimidine, and 1,3,5-triazine) was subjected to a computational study to determine the most suitable n-BuLi/heterocyclic ring; system as an initiator for the anionic polymerization of methyl methacrylate (MMA). These systems were suggested to prevent side reactions occurring through n-BuLi attack on the carbonyl carbon of MMA by sterically blocking the initiator. The initiation reaction was modeled with the B3LYP methodology 6-31+G*. Activation barriers were used to analyze the reactivity of each n-BuLi/heterocyclic ring system. Computational results showed that n-BuLi/triazine had a significantly lower activation barrier. Therefore, n-BuLi/triazine was the suggested initiator system for the anionic polymerization of poly(methyl methacrylate). (C) 2004 Wiley Periodicals, Inc.