变温核磁共振研究可溶性聚合物负载膦-银配合物。

Variable-temperature NMR studies of soluble polymer-supported phosphine-silver complexes.

机构信息

Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA.

出版信息

J Org Chem. 2010 Feb 5;75(3):873-8. doi: 10.1021/jo902427w.

PMID:20063851

Abstract

The use of polymers as supports for organometallic catalysts has received wide attention. However, catalyst reactivity is sometimes altered as a consequence of catalyst immobilization by a polymeric ligand and such altered reactivity can complicate such supported catalysts' use. The results in this study show that heptane phase selectively soluble polyisobutylene (PIB)-bound phosphine ligands have essentially identical kinetic behavior when compared to electronically similar isobutyldiphenylphosphine analogues in phosphine coordination and exchange in silver(I) halide complexes. These studies used variable-temperature (31)P NMR spectroscopy to probe the silver-phosphine exchange processes for both AgI and AgCl complexes of these polymeric and low molecular weight phosphine ligands. The results show that the dynamic behavior of the PIB- and isobutyldiphenylphosphine-AgX complexes is nearly identical based on line-shape analysis of these (31)P NMR spectra as a function of temperature. Similar studies of more polar poly(ethylene glycol)triarylphosphine-bound AgX complexes and electronically analogous low molecular weight AgX complexes have similar behavior in variable-temperature (31)P NMR spectroscopy.

摘要

聚合物作为有机金属催化剂的载体受到了广泛关注。然而，由于聚合物配体的固定化作用，催化剂的反应活性有时会发生变化，这种变化的反应性会使负载催化剂的使用复杂化。本研究结果表明，与电子相似的异丁基二苯基膦类似物相比，在银（I）卤化物配合物中膦配位和交换时，具有选择性溶解于庚烷相的聚异丁烯（PIB）键合膦配体的动力学行为基本相同。这些研究使用变温（31）P NMR 光谱法来探测这些高分子量和低分子量膦配体的 AgI 和 AgCl 配合物的银-膦交换过程。结果表明，基于这些（31）P NMR 光谱随温度的线形分析，PIB 和异丁基二苯基膦-AgX 配合物的动态行为几乎相同。对更极性的聚（乙二醇）三芳基膦键合 AgX 配合物和电子类似的低分子量 AgX 配合物的类似研究在变温（31）P NMR 光谱中也表现出类似的行为。