Synthesis and characterization of molecular rectangles of half-sandwich p-cymene ruthenium complexes bearing oxamidato ligands
作者:Wan-Zheng Zhang、Ying-Feng Han、Yue-Jian Lin、Guo-Xin Jin
DOI:10.1039/b909357e
日期:——
A series of binuclear half-sandwich p-cymene ruthenium complexes bearing oxamidato ligands [(p-cymene)2Ru2(μ-N,N′-bis(aryl)oxamidato)Cl2] (1–3) was synthesized by the reactions of the lithium salts of oxamide with [(p-cymene)RuCl2]2, respectively. Treatment of the binuclear complexes (1–3) with bidentate ligands such as 4,4′-bipyridine (4,4′-bpy) and trans-1,2-bis(4-pyridyl)ethylene (bpe) in the presence of AgOTf (OTf = CF3SO3) gave the corresponding tetranuclear complexes generally formulated as [(p-cymene)4Ru4(μ-N,N′- bis(aryl)oxamidato)2(μ-4,4′-bpy)2](OTf)4 (4a–c) and [(p-cymene)4Ru4(μ-N,N′-bis(aryl)oxamidato)2(μ-bpe)2](OTf)4 (5a–c) in high yields. All compounds (1–3, 4a–5c) have been characterized by NMR and IR spectra and elemental analyses. The molecular structures of 1, 4a and 5a have been determined by single-crystal X-ray analyses. The molecular structures of tetranuclear complexes 4a and 5a showed that two binuclear fragments as building blocks were connected by 4,4′-bpy or bpe to construct a rectangular cavity with the dimensions 5.57 × 11.28 Å (4a) and 5.56 × 13.65 Å (5a).
一系列含有oxamidato配体的双核半三明治结构的二茂铁配合物[(p-cymene)2Ru2(μ-N,N′-双(芳基)oxamidato)Cl2](1–3)通过oxamide的锂盐与[(p-cymene)RuCl2]2反应合成。在AgOTf (OTf = CF3SO3)存在下,双核配合物(1–3)与二齿配体如4,4′-联吡啶(4,4′-bpy)和反式-1,2-双(4-吡啶基)乙烯(bpe)反应,得到相应的四核配合物,一般表示为[(p-cymene)4Ru4(μ-N,N′-双(芳基)oxamidato)2(μ-4,4′-bpy)2](OTf)4 (4a–c)和[(p-cymene)4Ru4(μ-N,N′-双(芳基)oxamidato)2(μ-bpe)2](OTf)4 (5a–c),产率较高。所有化合物(1–3, 4a–5c)均通过NMR和IR光谱以及元素分析进行了表征。通过单晶X射线分析确定了1、4a和5a的分子结构。四核配合物4a和5a的分子结构显示,两个双核片段作为构建模块通过4,4′-bpy或bpe连接,形成一个尺寸为5.57 × 11.28 Å(4a)和5.56 × 13.65 Å(5a)的长方形空腔。