1D-O2-1800 PDF
ヒンダードアミン系光安定剤のMALDIマススペクトルにおけるフラグメンテーション機構の量子化学的研究 I. コハク酸ジメチルと4-ヒドロキシ-2,2,6,6-テトラメチル-1-ピペリジンエタノールの重縮合物
The fragmentation mechanisms in protonated molecule of dimethyl succinate-4- hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol polymer (Tinuvin 622) were investigated using MALDI MS/MS, ab initio DFT and semi-empirical PM6 MO methods. Two series of fragment peaks were observed at intervals of 283-Da in MALDI mass spectra of Tinuvin 622. The potential energy surfaces for the formation of m/z 216 ions were calculated with both stepwise and concerted mechanism. The barrier energy for the fragmentation process by the stepwise mechanism calculated using B3LYP/6-31G(d) was 71.7 kJ/mol smaller than that of the concerted mechanism.