Synthesis and Structural Characterization of Zn and Mg Complexes Supported by Tetradentate Amino-Benzotriazole Phenoxide Ligands : Efficient Catalysts for Ring-Opening Polymerization of Cyclic Esters

• Main Authors: Chang-Yu Sung, 宋昌豫
• Other Authors: Bao-Tsan Ko
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/jvnmh3

碩士 === 中原大學 === 化學研究所 === 99 === Two novel amino-benzotriazole phenol ligands, 2-(2H-benzotriazol-2-yl) -6-((N,N,N-trimethylethylenediamine)methyl)-4-tert-octylphenyl-phenol and 2- (2H-benzotriazol-2-yl)-6-((N-(2-methoxyethyl)methylamine)methyl)-4-tert-octylphenyl-phenol (C8NNBTP-H,C8NOBTP-H) were prepared though the Mannich condensation of 4-tert-octylphenyl-2-(2H-benzotriazol-2-yl)phenol with the mixtures of excess paraformaldehyde and N,N,N-trimethylethylenediamine) methylamine or N-(2-methoxyethyl)methyl amine under reflux condition. Zinc and magnesium complexes (1-6) supported by amino-benzotriazole phenoxide ligands were synthesized and fully characterized. Among them, complex 1 and 4 are demonstrated to catalyze ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and L-lactide in the presence of 9-anthracenemethanol. However, the catalytic activity and “controlled” character of complex 4 are higher than those of complex 1. Additionally, complex 4 is also a good catalyst for “controlled” ROP of β-butyrolactone (β-BL). To examine stereoselectivity of PLAs, complex 1 and 4 were employed as catalysts towards ROP of rac-lactide. Expermental results exhibit that complex 1 catalyzes LA to produce stereoblock isotactic-enrich PLA (Pm=0.59), and complex 4 favors to yield heterotactic-enrich PLA (Pr=0.65). According to spectroscopic studies of UV-Vis and PL in bis-adduct complexes 2, 3, 5 and 6. We found that absorption and emission wavelengths of complexes are red-shifted in comparison with those of ligands (L1 and L2). It’s believed that the little red-shift (＜20nm) results from the change of ligand structure after coordinating to the metal center.