Synthesis, Palladium(II) Complexes, and Catalytic Use of a Phosphanylferrocene Ligand Bearing a Guanidinium Pendant

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• 作者：Ondřej B&aacute ; rta ; Ivana C&iacute ; sařov&aacute ; and Petr Štěpnička
• 刊名：European Journal of Inorganic Chemistry
• 出版年：2017
• 出版时间：January 10, 2017
• 年：2017
• 卷：2017
• 期：2
• 页码：489-495
• 全文大小：1028K
• ISSN：1099-0682c

文摘

A polar phosphanylferrocene donor equipped with a hydrophilic guanidinium pendant, Ph₂PfcCH₂NHC(NH)NH₂·HCl (1·HCl; fc = ferrocene-1,1′-diyl), has been prepared from the corresponding amine hydrochloride, Ph₂PfcCH₂NH₂·HCl (2·HCl), and studied as a ligand for Pd^II. The reactions of 1·HCl with [PdCl₂(MeCN)₂] in 1:1 and 1:2 Pd/ligand ratios led to an unexpected zwitterionic complex, [PdCl₃(1H-κP)] (3), and the expected bis(phosphane) complex, trans-[PdCl₂(1H-κP)₂]Cl₂ (4), which were structurally characterized. The defined and air-stable solvated complex 3·Me₂CO and the in situ generated Pd(OAc)₂/1·HCl system were found to be active catalysts for the Suzuki–Miyaura cross-coupling of anionic triolborates with aryl bromides, giving the corresponding biphenyls. These reactions, which do not require the presence of an additional base, were advantageously performed in aqueous ethanol, and the coupling products were isolated in good to excellent yields.