Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Chemistry. 2018 Sep 20;24(53):14254-14268. doi: 10.1002/chem.201803067. Epub 2018 Aug 29.
A series of tris(pyrazolyl)alkane (RCTp) scorpionate ligands of the type RCTp (R=Me, nBu, SiMe ; R'=H, Me, Ph, iPr, tBu) were synthesized and their ability to coordinate methylmagnesium moieties was examined. The reaction of Mg(AlMe ) with neutral proligands HCTp or Me SiCTp , containing a non-innocent backbone methine moiety, led to deprotonation/rearrangement and SiMe /AlMe exchange to afford [(Me AlCTp ) Mg] and [(Me AlCTp )Mg(AlMe )], respectively, with monoanionic tripodal ligands. Treatment of sterically less demanding RCTp with Mg(AlMe ) produced isostructural dicationic "metal-in-a-box" complexes of the type [(RCTp ) Mg][AlMe ] (R=Me, nBu; R'=H, Me). Utilization of the superbulky ligands MeCTp and MeCTp gave monocationic complexes [(MeCTp )MgMe][AlMe ] and [(MeCTp )MgMe][Al Me ] as separated ion pairs. The reaction of Mg(AlMe ) with nBuCTp led to the formation of the dimagnesium complex [{(nBuCTp )Mg(AlMe )} (μ-CH )], which features a bridging methyl moiety and terminal η -coordinated tetramethylaluminato ligands. Isopropyl-substituted ligand MeCTp emerged from further fine-tuning of the steric and electronic parameters and, upon reaction with Mg(AlMe ) , gave (MeCTp )Mg(AlMe ) ; this represents the first example of a magnesium bis(alkyl) complex with an intact RCTp 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].
一系列三（吡唑基）烷（RCTp）螺环配体，类型 RCTp（R=Me，nBu，SiMe ；R'=H，Me，Ph，iPr，tBu）被合成出来，并对其与甲基镁部分配位的能力进行了研究。Mg(AlMe )与中性前体配体 HCTp 或 Me SiCTp（含有非亲核骨架亚甲基部分）反应，导致去质子化/重排和 SiMe /AlMe 交换，分别得到单核三齿配体的[(Me AlCTp )Mg]和[(Me AlCTp )Mg(AlMe )]。使用空间位阻要求较低的 RCTp 与 Mg(AlMe )反应，生成结构相同的二价阳离子“金属在盒子里”型配合物[(RCTp )Mg][AlMe ]（R=Me，nBu；R'=H，Me）。利用超支化配体 MeCTp 和 MeCTp，得到单核配合物[(MeCTp )MgMe][AlMe ]和[(MeCTp )MgMe][Al Me ]，作为分离的离子对。Mg(AlMe )与 nBuCTp 反应生成二镁配合物[{(nBuCTp )Mg(AlMe )}（μ-CH ）]，其特征是桥接甲基部分和末端 η 配位的四甲基铝酸盐配体。异丙基取代配体 MeCTp 是进一步精细调整空间位阻和电子参数的结果，与 Mg(AlMe )反应后，得到(MeCTp )Mg(AlMe )；这是第一个具有完整 RCTp 配体的镁双（烷基）配合物的例子。根据 Allen 等人开发的数学分析[J. Comput. Chem. 2013, 34, 1189-1197]，确定了所有镁配合物的确切配体锥角 Θ。
