Halikowska-Tarasek Katarzyna, Bisz Elwira, Siodłak Dawid, Dziuk Błażej, Ochędzan-Siodłak Wioletta
Department of Chemistry and Pharmacy, Opole University, Oleska 48, 45-052 Opole, Poland.
Department of Chemistry, Wroclaw University of Science and Technology, Norwida 4/6, 50-373 Wroclaw, Poland.
Int J Mol Sci. 2025 Jul 12;26(14):6691. doi: 10.3390/ijms26146691.
The polymerization of norbornene can occur via ring-opening metathesis polymerization (ROMP) or vinyl-addition pathways, each yielding polynorbornene with distinct structures and properties. This study reports on the synthesis and catalytic application of a new class of vanadium(III) and nickel(II) complexes bearing -heterocyclic carbene ligands, based on the IPr* framework, for the polymerization of norbornene. The vanadium(III) complexes, activated by diethylaluminum chloride and in the presence of ethyl trichloroacetate, showed activity in ROMP. In contrast, the nickel(II) complexes, activated by methylaluminoxane, exhibited catalytic activity toward vinyl-addition polymerization. Characterization by GPC, NMR, and FTIR confirmed the formation of both ring-opening metathesis polymerization and vinyl-type-derived polynorbornenes, with vinyl-type polymers showing significantly higher molecular weights. Structural variations in the -heterocyclic carbene ligands, particularly the linker length between imidazole donors, were found to strongly influence polymer molecular weight and the morphology of polynorbornenes.
降冰片烯的聚合反应可通过开环易位聚合（ROMP）或乙烯基加成途径发生，每种途径都会生成具有不同结构和性质的聚降冰片烯。本研究报道了一类基于IPr*骨架、带有-杂环卡宾配体的新型钒（III）和镍（II）配合物用于降冰片烯聚合的合成及催化应用。由二乙基氯化铝活化并在三氯乙酸乙酯存在下的钒（III）配合物在ROMP中表现出活性。相比之下，由甲基铝氧烷活化的镍（II）配合物对乙烯基加成聚合表现出催化活性。通过凝胶渗透色谱法（GPC）、核磁共振（NMR）和傅里叶变换红外光谱（FTIR）进行的表征证实了开环易位聚合和乙烯基型衍生聚降冰片烯的形成，其中乙烯基型聚合物显示出明显更高的分子量。发现-杂环卡宾配体的结构变化，特别是咪唑供体之间的连接链长度，对聚合物分子量和聚降冰片烯的形态有强烈影响。
