The synthesis and characterization of two homoleptic Zn(II)- and Mg(II)-complexes based on a simple tridentate {NNO} ligand are reported. The production of biocompatible atactic poly(lactic acid) (PLA) under industrially relevant melt conditions is demonstrated, noting high activity for Zn(1)₂ at room temperature in CH₂Cl₂ (TOF = 184 h^–1). Mg(1)₂ and Zn(1)₂ were shown to facilitate rapid PLA methanolysis into methyl lactate (Me-LA) under mild conditions, achieving up to 85% Me-LA yield within 30 min at 50 °C in THF. Further kinetic analysis found Mg(1)₂ and Zn(1)₂ to exhibit k_app values of 0.23 ± 0.0076 and 0.15 ± 0.0029 min^–1, respectively {8 wt % cat. loading}, among the highest reported thus far. Zn(1)₂ retained excellent activity for both poly(ethylene terephthalate) (PET) and poly(ε-caprolactone) (PCL) degradations, demonstrating catalyst versatility. Various upcycling strategies (e.g., methanolysis, glycolysis, and aminolysis) were employed to achieve a broad substrate scope, which included bis(2-hydroxyethyl) terephthalate (BHET), high value terephthalamides, and methyl 6-hydroxyhexanoate. Optimal glycolysis conditions using Zn(1)₂ enabled 64% BHET yield within 1 h at 180 °C, a rare example of PET glycolysis mediated by a discrete homogeneous metal-based catalyst. The application of such catalysts for PET aminolysis and PCL methanolysis has been reported for the first time.

中文翻译：

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三齿 {ONN} 配体的 Zn(II)-和 Mg(II)-配合物：在聚乳酸生产和聚酯化学升级中的应用

报道了基于简单三齿 {NNO} 配体的两种均质 Zn(II)-和 Mg(II)-配合物的合成和表征。展示了在工业相关熔体条件下生产生物相容性无规聚乳酸 (PLA)，注意到室温下在 CH ₂ Cl _{2 中}Zn( 1 ) _{2 的}高活性（TOF = 184 h ^–1）。Mg( 1 ) ₂和 Zn( 1 ) ₂显示出在温和条件下促进 PLA 快速甲醇分解为乳酸甲酯 (Me-LA)，在 50°C 的 THF 中，在 30 分钟内实现高达 85% 的 Me-LA 产率。进一步的动力学分析发现 Mg( 1 ) ₂和Zn（1）₂到表现出ķ_应用的0.23±0.0076和0.15±0.0029最小值^-1，分别{8％（重量）的猫。加载}，是迄今为止报告的最高值之​​一。Zn( 1 ) ₂对聚(对苯二甲酸乙二醇酯) (PET) 和聚(ε-己内酯) (PCL) 降解均保持优异的活性，证明了催化剂的多功能性。各种升级策略（例如甲醇分解、糖酵解和氨解）被用来实现广泛的底物范围，包括对苯二甲酸双（2-羟乙基）酯 (BHET)、高价值的对苯二甲酰胺和 6-羟基己酸甲酯。使用 Zn( 1 ) _{2 的}最佳糖酵解条件在 180°C 下 1 小时内实现了 64% 的 BHET 产率，这是由离散的均质金属基催化剂介导的 PET 糖酵解的罕见例子。此类催化剂在PET氨解和PCL甲醇分解中的应用是首次报道。