In this study, the synthesis, spectroscopic and catalytic properties of PdLn (n = 1-6) complexes with tetradentate -ONNO- and -SNNS- type Schiff base ligands LnH2 (n = 1-6) were investigated. The PdLn (n = 1-6) complexes were synthesized by the thermal reactions of the Schiff bases and Pd(OAc)2 in acetonitrile and characterized by elemental analysis, FT-IR, 1H NMR, UV-visible and TGA/DTG. The spectroscopic studies suggest that all of the ligands are coordinated to the central metal as a tetradentate ligand coordinating via the central azomethine nitrogens (C=N) and phenolic oxygen/sulfur atoms. On the palladium-catalyzed Suzuki cross-coupling reactions employing PdLn (n = 1-6) complexes toward a various substituted arylbromides and boronic acids were pursued. The conversions were obtained and yields with different arylbromides were calculated and discussed. All the complexes were thermally stable and were not sensitive to air or the moisture. The complexes were easily prepared from low cost precursors that could be used as versatile and catalysts for different C-C coupling reactions (Suzuki-Miyaura reactions). Moreover steady state fluorescence emission and excitation spectra were measured. These studies have been shown that PdL2 and PdL3 dyes exhibited high fluorescence intensity and selective and efficient response to cobalt ions over other metal ions in buffered solutions.
在本研究中,探讨了具有四配位 -ONNO- 和 -SNNS- 型席夫碱
配体 LnH2 (n = 1-6) 的 PdLn (n = 1-6) 配合物的合成、光谱学和催化性质。PdLn (n = 1-6) 配合物是通过在
乙腈中将席夫碱与 Pd(OAc)2 进行热反应合成的,并通过元素分析、FT-IR、1H NMR、UV-可见光谱和热重分析/差热分析进行表征。光谱研究表明,所有
配体作为四齿
配体通过中心亚醛氮(C=N)和
酚羟基/
硫原子配位于中心
金属上。在使用 PdLn (n = 1-6) 配合物催化的铃木交叉耦合反应中,探讨了不同取代的芳基
溴化物和
硼酸的反应。获得了不同芳基
溴化物的转化率和产率,并进行了讨论。所有配合物热稳定,且对空气或湿气不敏感。这些配合物易于从低成本前体制备,可作为不同 C-C 耦合反应(铃木-宫裏反应)的多功能催化剂。此外,测量了稳态荧光发射和激发光谱。这些研究表明,Pd
L2 和 PdL3
染料对
钴离子表现出高荧光强度,并在缓冲溶液中对其他
金属离子具有选择性和高效响应。