Mechanistic Insights into Concerted C–C Reductive Elimination from Homoleptic Uranium Alkyls
Mechanistic Insights into Concerted C–C Reductive Elimination from Homoleptic Uranium Alkyls
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DOI：
10.1021/acs.organomet.7b00438
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发表时间：
2017-09
期刊：
影响因子：
2.8
通讯作者：
Sara A. Johnson;Robert F. Higgins;M. Abu‐Omar;M. P. Shores;Suzanne C. Bart
中科院分区：
文献类型：
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作者：
Sara A. Johnson;Robert F. Higgins;M. Abu‐Omar;M. P. Shores;Suzanne C. Bart
研究了同感铀（IV）烷基协同C-C还原消除的机理。在- 108℃下，用4个等量的KCH2-p-Cl-Ph （1-p-Cl）处理UCl4，合成了对氯铀（IV）四苯基衍生物U(CH2-p-ClC6H4)4 （2-Bn）、U(CH2-p-iPrC6H4)4 （2-p-iPr）、U(CH2-ptBu-C6H4)4 （2-p-tBu）、U(CH2-o-OMeC6H4)4 （2-o-OMe）和U(CH2-m-OMeC6H4)4 (2-m-OMe)，为之前报道的铀烷基配合物家族增加了新成员。该家族的每个成员都容易与氧化还原活性α-二亚胺配体MesDABMe (MesDABMe = [mecn = C(Me)C(Me) = NMes]反应；Mes = 2,4,6-三甲基苯基)，提供C-C还原消除的产物，即（MesDABMe）U(CH2Ph ')2和Ph ' ch2ch2ph ' （Ph ' = p-iPrC6H4, p-tBuC6H4, m-OMeC6H4, p-ClC6H4）。通过SQUID磁强计测得的室温磁化率值显示，随着取代基吸电子特性的增加，磁矩也随之增加。
A mechanistic study was carried out to probe concerted C–C reductive elimination from homoleptic uranium(IV) alkyls. The para-chloro uranium(IV) tetrabenzyl derivative, U(CH2–p-ClC6H4)4 (2-p-Cl), was synthesized by treating UCl4 with 4 equivalents of KCH2–p-Cl-Ph (1-p-Cl) at −108 °C, adding a new member to the previously reported family of uranium alkyl complexes U(CH2C6H5)4 (2-Bn), U(CH2–p-iPrC6H4)4 (2-p-iPr), U(CH2–ptBu-C6H4)4 (2-p-tBu), U(CH2–o-OMeC6H4)4 (2-o-OMe), and U(CH2–m-OMeC6H4)4 (2-m-OMe). Each member of this family readily reacts with the redox-active α-diimine ligand, MesDABMe (MesDABMe = [MesN═C(Me)C(Me)═NMes]; Mes = 2,4,6-trimethylphenyl), to afford the products from C–C reductive elimination, namely, (MesDABMe)U(CH2Ph′)2 and Ph′CH2CH2Ph′ (Ph′ = p-iPrC6H4, p-tBuC6H4, m-OMeC6H4, p-ClC6H4). Room-temperature magnetic-susceptibility values, obtained via SQUID magnetometry, show a correlation with an increase in the magnetic moment as the electron-withdrawing character of the substituent increas...