Magnesium Stung by Nonclassical Scorpionate Ligands: Synthesis and Cone-Angle Calculations.
Magnesium Stung by Nonclassical Scorpionate Ligands: Synthesis and Cone-Angle Calculations.
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DOI：
10.1002/chem.201803067
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发表时间：
2018-08
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影响因子：
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通讯作者：
Christoph Stuhl;C. Maichle‐Mössmer;R. Anwander
中科院分区：
文献类型：
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作者：
Christoph Stuhl;C. Maichle‐Mössmer;R. Anwander
合成了一系列三（吡唑基）烷烃（RCTp）蝎形配体RCTp 3-R'（R=Me，nBu，SiMe 3; R'= H，Me，Ph，iPr，tBu），并考察了它们与甲基镁的配位能力. Mg（AlMe 4）2与中性前配体HCTp 3-Ph或Me 3 SiCTp 3-Me（含有非无辜骨架次甲基部分）反应，导致去质子化/重排和SiMe 3/AlMe 3交换，分别得到具有单阴离子三脚架配体的[（Me 3 AlCTp 3-Ph）2 Mg]和[（Me 3 AlCTp 3-Me）Mg（AlMe 4）]。用Mg（AlMe 4）2处理空间要求较低的RCTp 3-R'产生[（RCTp 3-R'）2 Mg][AlMe 4]2（R=Me，nBu; R '= H，Me）类型的同构双阳离子“盒中金属”络合物。利用超体积配体MeCTp 3-Ph和MeCTp 3-tBu得到了作为分离离子对的单阳离子配合物[（MeCTp 3-Ph）MgMe][AlMe 4]和[（MeCTp 3-tBu）MgMe][Al 2 Me 7]。Mg（AlMe 4）2与nBuCTp 3-Ph反应生成了双镁配合物[{（nBuCTp 3-Ph）Mg（AlMe 4）}2（μ-CH 3）]，其特征在于桥连甲基和末端η1配位的四甲基铝酸根配体.异丙基取代的配体MeCTp 3-iPr从空间和电子参数的进一步微调中出现，并且在与Mg（AlMe 4）2反应时，得到（MeCTp 3-iPr）Mg（AlMe 4）2 ;这代表了具有完整RCTp 3-R'配体的镁双（烷基）络合物的第一个实例。根据由艾伦等人[J. Comput. Chem. 2013，34，1189-1197]。
A series of tris(pyrazolyl)alkane (RCTp) scorpionate ligands of the type RCTp3-R' (R=Me, nBu, SiMe3 ; R'=H, Me, Ph, iPr, tBu) were synthesized and their ability to coordinate methylmagnesium moieties was examined. The reaction of Mg(AlMe4 )2 with neutral proligands HCTp3-Ph or Me3 SiCTp3-Me , containing a non-innocent backbone methine moiety, led to deprotonation/rearrangement and SiMe3 /AlMe3 exchange to afford [(Me3 AlCTp3-Ph )2 Mg] and [(Me3 AlCTp3-Me )Mg(AlMe4 )], respectively, with monoanionic tripodal ligands. Treatment of sterically less demanding RCTp3-R' with Mg(AlMe4 )2 produced isostructural dicationic "metal-in-a-box" complexes of the type [(RCTp3-R' )2 Mg][AlMe4 ]2 (R=Me, nBu; R'=H, Me). Utilization of the superbulky ligands MeCTp3-Ph and MeCTp3-tBu gave monocationic complexes [(MeCTp3-Ph )MgMe][AlMe4 ] and [(MeCTp3-tBu )MgMe][Al2 Me7 ] as separated ion pairs. The reaction of Mg(AlMe4 )2 with nBuCTp3-Ph led to the formation of the dimagnesium complex [{(nBuCTp3-Ph )Mg(AlMe4 )}2 (μ-CH3 )], which features a bridging methyl moiety and terminal η1 -coordinated tetramethylaluminato ligands. Isopropyl-substituted ligand MeCTp3-iPr emerged from further fine-tuning of the steric and electronic parameters and, upon reaction with Mg(AlMe4 )2 , gave (MeCTp3-iPr )Mg(AlMe4 )2 ; this represents the first example of a magnesium bis(alkyl) complex with an intact RCTp3-R' ligand. The exact ligand cone angles Θ° of all magnesium complexes were determined according to the mathematical analysis developed by Allen et al. [J. Comput. Chem. 2013, 34, 1189-1197].