Synthesis of a Heteroleptic Pentamethylcyclopentadienyl Yttrium(II) Complex, [K(2.2.2-Cryptand)]{(C 5 Me 5 ) 2 Y II [N(SiMe 3 ) 2 ]}, and Its C–H Bond Activated Y(III) Derivative
Synthesis of a Heteroleptic Pentamethylcyclopentadienyl Yttrium(II) Complex, [K(2.2.2-Cryptand)]{(C 5 Me 5 ) 2 Y II [N(SiMe 3 ) 2 ]}, and Its C–H Bond Activated Y(III) Derivative
复制标题
杂配五甲基环戊二烯基钇(II)络合物[K(2.2.2-穴状配体)]{(C 5 Me 5 ) 2 Y II [N(SiMe 3 ) 2 ]}及其C-H键活化Y的合成
DOI：
10.1021/acs.organomet.1c00482
复制
发表时间：
2021
期刊：
影响因子：
2.8
通讯作者：
Evans, William J.
中科院分区：
文献类型：
--
作者：
Jenkins, Tener F.;Bekoe, Samuel;Ziller, Joseph W.;Furche, Filipp;Evans, William J.
为了确定Y（II）的C5 Me 5络合物是否可以被分离并检查杂配Y（II）络合物的合成可及性，检查了在2.2.2-穴状配体（crypt）存在下在THF中用钾石墨还原（C5 Me 5）2 YIII（NR 2）（R = SiMe 3）。形成深黑色溶液，其EPR光谱指示4d 1 Y（II）络合物，giso = 1.975和A（89 Y）= 74.5G。X射线衍射显示，产物的单晶含有65-75%的Y（II）络合物[K（crypt）][（C5 Me 5）2 YII（NR 2）]和25-35%的Y（III）环化衍生物[K（crypt）][（C5 Me 5）2 YIII {N（SiMe 3）（SiMe 2CH 2）-κC，κN}]的混合物，其由酰胺配体上SiMe 3取代基的甲基的C-H键活化产生。四甲基配合物（C5 Me 4 H）2 YIII（NR 2）的类似还原产生giso = 1.975和A（89 Y）= 71.2G的深色溶液。该产物的结晶还揭示了由10%/90% [K（crypt）][（C5 Me 4 H）2 YII（NR 2）]/环化的[K（crypt）][（C5 Me 4 H）2 YIII {N（SiMe 3）（SiMe 2CH 2）-κC，κN}]组成的Y（II）和Y（III）络合物的混合物，其与[K（crypt）][C5 Me 4 H]共结晶。密度泛函理论（DFT）研究表明，[（C5 Me 5）2 YII（NR 2）]1-和[（C5 Me 4 H）2 YII（NR 2）]1-的HOMO主要是4dz 2 in特征，SiMe 3甲基上的一些电子密度可能会增强C-H键活化反应性。
To determine if a C5Me5complex of Y(II) could be isolated and to examine the synthetic accessibility of heteroleptic Y(II) complexes, the reduction of (C5Me5)2YIII(NR2) (R = SiMe3) with potassium graphite in THF in the presence of 2.2.2-cryptand (crypt) was examined. An intensely dark colored solution is formed that has EPR spectra indicative of a 4d1Y(II) complex withgiso= 1.975 andA(89Y) = 74.5 G. X-ray diffraction revealed that single crystals of the product contained a 65–75% mixture of an Y(II) complex [K(crypt)][(C5Me5)2YII(NR2)] and 25–35% of an Y(III) cyclometalated derivative, [K(crypt)][(C5Me5)2YIII{N(SiMe3)(SiMe2CH2)-κC,κN}], arising from C–H bond activation of a methyl group of the SiMe3substituent on the amide ligand. An analogous reduction of the tetramethyl complex, (C5Me4H)2YIII(NR2), generated a dark solution withgiso= 1.975 andA(89Y) = 71.2 G. Crystallization of that product also revealed a mixture of Y(II) and Y(III) complexes comprised of 10%/90% [K(crypt)][(C5Me4H)2YII(NR2)]/cyclometalated [K(crypt)][(C5Me4H)2YIII{N(SiMe3)(SiMe2CH2)-κC,κN}], which co-crystallized with [K(crypt)][C5Me4H]. Density functional theory (DFT) studies indicate that the HOMOs of both [(C5Me5)2YII(NR2)]1–and [(C5Me4H)2YII(NR2)]1–are primarily 4dz2in character with some electron density on the SiMe3methyl groups that may enhance the C–H bond activation reactivity.