Sodium and Magnesium Complexes with Dianionic α-Diimine Ligands

A series of sodium and magnesium complexes with α-diimine ligands, [Na2(LiPr)(Et2O)]2 (1, LiPr = [(2,6-iPr2C6H3)N(Me)C]2), [Na2(LMes)(solv)2]2 (LMes = [(2,4,6-Me3C6H3)N(Me)C]2, 2a, solv = Et2O; 2b, solv = THF), [Na4(LEt)2]n (3, LEt = [(2,6-Et2C6H3)N(Me)C]2), and [Mg(LMes)(THF)3] (4), have been synthesized by reduction of the diimine ligands with sodium or magnesium metal. Single-crystal X-ray diffraction analysis revealed that the sodium complexes have a 2:1 [Na2L] unit that aggregates to dimeric (1, 2a, 2b) or polymeric (3) structures, while the magnesium complex (4) shows a monomeric 1:1 structure. In all compounds 1−4, the ligand is doubly reduced to a dianion. The two Na+ ions in 1, 2a, 2b, and 3 show different coordination modes, one of which is chelated by the N donors of a ligand with supplementary Na−C bonds to the phenyl ring of another ligand within the [Na2L]2 dimer, while the other is bonded by the central C2N2 core of the ligand and solvent molecules (1, 2a, and 2b). Compound 3 displays a novel three-dimensional network. The Mg2+ ion in 4 is coordinated by a ligand molecule and three THF molecules. Density functional theory (DFT) computations on the sodium and magnesium complexes 1 and 4 confirmed their electronic structures and the dianionic character of the ligands.

一系列以α-二胺配体为特征的钠和镁复杂化合物，包括[Na2(LiPr)(Et2O)]2（其中LiPr = [(2,6-iPr2C6H3)N(Me)C]2）、[Na2(LMes)(solv)2]2（LMes = [(2,4,6-Me3C6H3)N(Me)C]2，2a，solv = Et2O；2b，solv = THF）、[Na4(LEt)2]n（3，LEt = [(2,6-Et2C6H3)N(Me)C]2）以及[Mg(LMes)(THF)3]（4），通过二胺配体的钠或镁金属还原反应合成。单晶X射线衍射分析揭示了钠复杂化合物具有2:1的[Na2L]单元，该单元聚集成二聚体（1，2a，2b）或聚合物（3）结构，而镁复杂化合物（4）则展现出单分子1:1结构。在所有化合物1至4中，配体均被还原至二阴离子。在化合物1，2a，2b和3中，两个Na+离子表现出不同的配位模式，其中一种是配体N供体的螯合，并与另一个配体的苯环通过补充的Na-C键连接至[Na2L]2二聚体内部，另一种则是通过配体的中心C2N2核与溶剂分子结合（1，2a和2b）。化合物3展现出一种新颖的三维网络结构。在化合物4中，Mg2+离子被一个配体分子和三个THF分子配位。对钠和镁复杂化合物1和4进行的密度泛函理论（DFT）计算证实了它们的电子结构和配体的二阴离子特性。