Reactions of 9-Carbene-9-Borafluorene Monoanion and Selenium: Synthesis of Boryl-Substituted Selenides and Diselenides
Reactions of 9-Carbene-9-Borafluorene Monoanion and Selenium: Synthesis of Boryl-Substituted Selenides and Diselenides
复制标题
9-卡宾-9-硼芴单阴离子与硒的反应：硼基取代的硒化物和二硒化物的合成
DOI：
10.1021/acs.inorgchem.1c02124
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发表时间：
2021
影响因子：
4.6
通讯作者：
Gilliard, Robert J.
中科院分区：
文献类型：
--
作者：
Wentz, Kelsie E.;Molino, Andrew;Freeman, Lucas A.;Dickie, Diane A.;Wilson, David J.;Gilliard, Robert J.
本文报道了9-卡宾-9-硼芴单阴离子（1）与硒及含硒试剂的反应。当化合物1与灰色硒在THF中反应时，产生各种硼基取代的硒化物和二硒化物（2-6），包括由卡宾配体Dipp基团（Dipp = 2，6-二异丙基苯基）迁移产生的分子。然而，当1和灰色硒在甲苯中在18-冠-6存在下进行类似的反应时，得到硼基取代的硒化物7作为唯一的含硼产物。由于化合物7是有机硒醚3的单体变体，因此18-冠-6促进了产物选择性和在非极性溶剂中的溶解性。通过1与Se 2Cl 2在THF中的反应，直接分离出具有反式B-Se-Se-B核的二硒醚5。计算模型表明，5的形成是通过一种自由基机制进行的。这得到了一项实验的支持，该实验表明CAAC-硼杂环戊二烯基也与SeCl 2反应，生成5 [CAAC =（2，6-二异丙基苯基）-4，4-二乙基-2，2-二甲基-吡咯烷-5-亚基]。5的能量分解分析表明硼杂茂烯-二硒键是共价键（ΔEint，−168.9 kcal mol-1）。通过单晶X射线衍射和多核核磁共振（1H，13 C，11B和77 Se）对所有新化合物进行了表征。
Reactions of 9-carbene-9-borafluorene monoanion (1) with elemental selenium and selenium-containing reagents are reported. When compound1is reacted with grey selenium in THF, various boryl-substituted selenides and diselenides are produced (2–6), including molecules resulting from migration of the carbene ligand Dipp group (Dipp = 2,6-diisopropylphenyl). However, when a similar reaction between1and grey selenium is performed in toluene in the presence of 18-crown-6, boryl-substituted selenide7is obtained as the sole boron-containing product. As compound7is the monomeric variant of organoselenide3, 18-crown-6 promotes both product selectivity and solubility in a nonpolar solvent. Diselenide5, which features a trans-bent B–Se–Se–B core, was directly isolated via reaction of1with Se2Cl2in THF. Computational modeling suggests that the formation of5proceeds via a radical mechanism. This was supported by an experiment demonstrating that the CAAC-borafluorene radical also reacts with SeCl2to yield5[CAAC = (2,6-diisopropylphenyl)-4,4-diethyl-2,2-dimethyl-pyrrolidin-5-ylidene]. Energy decomposition analysis of5indicates a covalent borafluorene–diselenide bond (ΔEint, −168.9 kcal mol–1). All of the new compounds were fully characterized via single-crystal X-ray diffraction and multinuclear nuclear magnetic resonance (1H,13C,11B, and77Se).