The synthesis of unsymmetrical β‐diketimines with N‐aryl‐N′‐alkyl substitution require at least two condensation steps and tedious purification procedures. An improvement in the preparation of four unsymmetrical N‐aryl‐N′‐alkylpyridyl β‐diketimine ligands (HL1–HL4) using 5‐Å molecular sieves is reported. The synthesis of four Li complexes (LiL1, LiL2, LiL3, and LiL4) containing N‐aryl‐N′‐alkylpyridyl β‐diketimines ligands is also presented. All four Li complexes were fully characterized by ¹H NMR spectroscopic, ¹³C NMR spectroscopic, and elemental analyses. X‐ray structure analysis and spectroscopic results indicate that the Li β‐diketimine structures and ligand binding modes are governed by the bulkiness of the N‐aryl substituent and the length of the pyridyl arm of the N‐aryl‐N′‐alkyl β‐diketiminate ligand.

中文翻译：

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使用分子筛及其锂配合物改进不对称N-芳基-N'-烷基吡啶基-二酮亚胺的合成

具有N-芳基-N'-烷基取代基的不对称β-二酮亚胺的合成至少需要两个缩合步骤和繁琐的纯化程序。据报道，使用5Å分子筛制备了四个不对称的N-芳基-N'-烷基吡啶基β-二酮亚胺配体（H L1- H L4）有所改进。还介绍了四个含有N-芳基-N'-烷基吡啶基β-二酮亚胺配体的Li配合物（Li L1，Li L2，Li L3和Li L4）的合成。所有四个Li络合物的特征均由^1表示1 H NMR光谱，¹³ C NMR光谱和元素分析。X射线结构分析和光谱结果表明，锂β-二酮亚胺结构和配体结合模式由的膨松度支配Ñ -芳基取代基和的吡啶基臂的长度Ñ -芳基- N' -烷基β-二酮化配体。