1016235-29-2Relevant academic research and scientific papers
Synthesis, characterization, and catalysis in ε-caprolactone polymerization of aluminum and zinc complexes supported by N,N,N-chelate ligands
Chai, Zuo-Yun,Zhang, Cheng,Wang, Zhong-Xia
, p. 1626 - 1633 (2009/01/31)
A series of aluminum and zinc complexes supported by pyridine-based N,N,N-chelate ligands have been synthesized and characterized. Treatment of 2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-((trimethylsilyl) methyl)pyridine (2) with LiBun/tmeda and then PhCN afforded a lithium complex [Li[2-(3,5-Me2C3HN2)-6-{N(SiMe 3)C(Ph)=CH}C5H3N}] ([LiL]) (3). Reaction of 3 with ZnCl2 formed corresponding zinc chloride complex [Zn(Cl)L] (4), which was transformed to methyl- or ethylzinc complex [Zn(R)L] (R = Me, 5a; R = Et, 5b) by treatment with methyl- or ethyllithium. The ethylzinc complex (5b) was also generated by reaction of 4 with LiHBEt3. Reaction of 4 with AlR3 (R = Me, Et) gave alkyl aluminum chloride complexes [Al(Cl)(R)L] (R = Me, 6a; R = Et, 6b). Structurally similar N,N,N-chelate zinc complex [Zn(Et){2-(3,5-Me2C3HN2)-6-{N(Ph)P(Ph 2)=CH}C5H3N}] (9) was obtained by reaction of 2-(3,5-Me2C3HN2)-6-[PhN=P(Ph) 2CH2}C5H3N (8) with ZnEt 2. The aluminum and zinc complexes bearing [{2-{N(SiMe 3)=P(Ph)2}-6-{N(SiMe3)P(Ph)2=CH} C5H3N}]- ligand, 14 and 15, were similarly prepared by reaction of 2-{Me3SiN=P(Ph)2}-6-(Me 3SiN=P(Ph)2CH2)C5H3N with AlEt3 and ZnEt2, respectively. The new compounds were characterized by NMR spectroscopy and elemental analyses. The molecular structures of complexes 5a, 9, 14, and 15 were determined by single-crystal X-ray diffraction techniques. The catalysis of complexes 5a, 6a, 14, and 15 in the ring-opening polymerization of ε-caprolactone was evaluated.
