When a pincer-ligated iridium complex with a phosphinite substituent in the para-position of the aromatic backbone is immobilized on γ-alumina, it becomes a highly effective supported catalyst for the transfer-dehydrogenation of alkanes. The nature of the interaction between the organometallic complex and the support was investigated using solid-state 31P MAS NMR spectroscopy, solution-state 1H and 31P1H} NMR spectroscopy, IR and GC/MS analysis of extracted reaction products. The phosphinite substituent is cleaved from the pincer ligand by its reaction with hydroxyl groups on the γ-alumina surface, resulting in covalent anchoring of the complex via the aryl ring. A similar reaction occurs on silica, allowing for ready grafting onto this support as well. A strategy for anchoring homogeneous catalysts on hydroxyl-terminated oxide supports though the selective cleavage of [POR]-containing ligand substituents is suggested.
当芳香主链对位具有次
亚膦酸酯取代基的钳式连接
铱配合物固定在γ-氧化铝上时,它成为
烷烃转移脱氢的高效负载型催化剂。使用固态 31P MAS NMR 光谱、溶液态 1H 和 31P1H} NMR 光谱、萃取反应产物的 IR 和 GC/MS 分析,研究了有机
金属配合物与载体之间相互作用的性质。次
亚膦酸酯取代基通过与 γ-氧化铝表面上的羟基反应而从钳形
配体上裂解下来,从而通过芳环实现络合物的共价锚定。类似的反应发生在
二氧化硅上,也可以随时接枝到该载体上。提出了一种通过选择性裂解含[POR]的
配体取代基将均相催化剂锚定在羟基封端的氧化物载体上的策略。