Palladium(<scp>ii</scp>)-selenated Schiff base complex catalyzed Suzuki–Miyaura coupling: Dependence of efficiency on alkyl chain length of ligand
作者:Gyandshwar Kumar Rao、Arun Kumar、Bharat Kumar、Dinesh Kumar、Ajai Kumar Singh
DOI:10.1039/c1dt11695a
日期:——
The new selenated Schiff bases L1âL4 which differ in the chain lengths (longest in L4) of non-coordinating substituents and their square planar complexes [Pd(LâH)Cl] (1â4) [L = L1âL4, behaving as (Se, N, Oâ) ligand] have been synthesized and characterized by multinuclei NMR. The molecular structure of 1 has been elucidated by X-ray diffraction on its single crystal [PdâSe = 2.3965(9) Ã
]. All the complexes 1â4 (0.5 mol%) have been found suitable to catalyze SuzukiâMiyaura coupling reactions under mild conditions. The activity of 4 which has ligand L4 has been found highest. The formation of palladium(0) nano-particles (NPs) stablilized by organoselenium species appears to be the catalytic pathway. The length of the pendent alkyl chain present in the complex molecule unprecedentedly controls the dispersion and composition of these particles and consequently the catalytic activity.
我们合成了新的硒化希夫碱 L1âL4 及其方形平面配合物 [Pd(LâH)Cl] (1â4) [L = L1âL4, 行为为 (Se, N, Oâ) 配体],并通过多核核磁共振对其进行了表征。通过对 1 的单晶体进行 X 射线衍射[PdâSe = 2.3965(9) Ã ],阐明了 1 的分子结构。研究发现,所有的配合物 1â4 (0.5 mol%) 都适合在温和的条件下催化铃木-米亚乌拉偶联反应。其中配体 L4 的活性最高。有机硒稳定化的钯(0)纳米颗粒(NPs)的形成似乎是催化途径。复合物分子中存在的垂烷基链的长度前所未有地控制着这些微粒的分散和组成,从而控制着催化活性。