还原法制备二配位β-二亚胺镓卡宾及其结构表征

Structural Characterizations for Two-Coordinateβ-Diketiminato Gallium(Ⅰ)Carbene Analogue Synthesized via Reduction

侧链无活性位点的β‑二亚胺配体具有对低价金属中心良好的电子稳定效应和侧基保护作用。金属K能够还原β‑二亚胺二氯合镓􀃮化合物PhC(PhCN‑Dip)_(2)GaCl_(2)(2,Dip=2,6‑^(i)Pr_(2)C_(6)H_(3)),以较高产率得到新一例β‑二亚胺稳定的分子态Ga􀃬卡宾单体PhC(PhCN‑Dip)_(2)Ga:(3)。化合物2和3的结构与组成通过X射线单晶衍射与NMR进行表征。单体镓卡宾3中心Ga􀃬离子处于平面六元氮杂环的一个顶角,具有弯曲二配位的几何构型。理论计算结果显示,3的HOMO能级较低,被Ga的孤对电子占据,LUMO+1对应Ga的空p轨道,但是能级比HOMO要高601.0 kJ·mol^(-1),这表明3是一个与氮杂环碳卡宾同构的镓卡宾分子,且Ga􀃬离子的孤对电子具有较好的热稳定性。

Theβ-diketiminate ligands without substituents containing active sites exhibit good electron stabilization effect and sterically protection for the low-valent metal center.Potassium was able to reduceβ-diketiminato gallium(Ⅲ) dichloride PhC(PhCN-Dip)_(2)GaCl_(2)(2,Dip=2,6-^(i)Pr_(2)C_(6)H_(3))to highly yield a newβ-diketiminato gallium(Ⅰ) carbene analogue PhC(PhCN-Dip)_(2)Ga:(3)as a monomeric molecule.The structures and composition of compounds 2 and 3 were characterized by the X-ray single-crystal diffraction and the NMR spectroscopies.The central Ga(Ⅰ)ion of 3 occupies a point angle of the six-membered N-heterocyclic plane with a distorted two-coordinate geometry.Theoretical calculations show that the HOMO corresponded to the lone pair electrons at the Ga center,which had a low energy level of-6.352 eV,while the LUMO+1 was associated with the empty p-orbital of Ga with an energy of 601.0 kJ·mol^(-1) higher than the HOMO,indicating that 3 is a gallium(Ⅰ)carbene analogue and isostructural to N-heterocyclic carbene,and the lone pair of Ga(Ⅰ)ion has good thermal stability.CCDC:2123086,2;2123087,3.