Catalytic investigations of carbon-carbon bond-forming reactions by a hydroxyapatite-bound palladium complex
Catalytic investigations of carbon-carbon bond-forming reactions by a hydroxyapatite-bound palladium complex
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DOI：
10.1039/b506129f
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Kaneda, K
中科院分区：
文献类型：
--
作者：
Mori, K;Hara, T;Kaneda, K
在丙酮溶液中，用PdCl2(PHCN)(2)与非化学计量比的缺钙羟基磷灰石Ca-9(HPO4)(PO4)(5)(OH)反应，合成了一种新型的羟基磷灰石-钯配合物(PdHAP-1)。物理化学方法表征表明，Pd-II磷酸配合物在缺钙位生成，对芳基溴化物的Mizoroki-Heck反应和Suzuki-Miyaura偶联反应表现出良好的催化活性。XAFS分析证实，羟基磷灰石催化剂的高催化活性归因于Pd单体结构的异常强韧，其中Pd被阴离子磷酸配体包围。实验还证明，在调节溶剂体系后，PdHAP-1能够在四丁基溴化铵存在下催化活性芳香氯的Suzuki-Miyaura偶联反应。在此条件下，羟基磷灰石表面原位生成的Pd纳米团簇是一种有效的催化活性物种。
A new type of hydroxyapatite- bound palladium complex ( PdHAP- 1) was synthesized by treatment of a nonstoichiometric Ca-deficient hydroxyapatite, Ca-9(HPO4)( PO4) (5)( OH), with PdCl2( PhCN)(2) in acetone solution. Characterization by means of physicochemical methods revealed that a monomeric Pd-II phosphate complex could be generated at a Ca-deficient site, which displayed outstanding catalytic activities for the Mizoroki - Heck reaction and Suzuki - Miyaura coupling reaction of aryl bromides. The remarkably high catalytic activity of the hydroxyapatite catalyst is ascribed to the exceptionally robust monomeric Pd structure, in which Pd is surrounded by anionic phosphate ligands, as confirmed by XAFS analysis. It is also proven that, upon adjustment of the solvent system, the PdHAP- 1 was able to catalyze the Suzuki - Miyaura coupling of activated aryl chlorides in the presence of TBAB. Under such conditions, the in situ generated Pd nanocluster on the surface of hydroxyapatite was effective as a catalytically active species.