Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Mohali 140306, Punjab, India.
Dalton Trans. 2019 Dec 3;48(47):17472-17478. doi: 10.1039/c9dt03382c.
The reactivity of a bicyclic (alkyl)(amino)carbene (BICAAC) towards different boranes has been examined in the present work. The reactions with boranes BX3·SMe2 (X = H, Cl, Br), BF3·OEt2 and BCl3 yield Lewis adducts [BICAAC·BH3] (1), [BICAAC·BHCl2] (2), [BICAAC·BH2Cl] (3), [BICAAC·BF3] (4), [BICAAC·BCl3] (5) and [BICAAC·BBr3] (6) respectively, whereas more hydridic boranes, 9-borabicyclo[3.3.1]nonane (9-BBN) and catecholborane (HBcat), enable the insertion of the carbene carbon into the B-H bond to form [BICAAC(H)-(9-BBN)] (7) and [BICAAC(H)-Bcat] (8). These complexes are the first examples of BICAAC-boron compounds and have been characterized using IR, multinuclear NMR spectroscopy, HRMS spectrometry and single crystal X-ray diffraction. Computational analyses were also performed to gain insight into the mechanism of B-H bond activation and adduct formation. Furthermore, the reactions of the BICAAC with boranes have been compared with the known reactions of CAACs and NHCs.
本工作研究了双环（烷基）（氨基）卡宾（BICAAC）与不同硼烷的反应性。与硼烷 BX3·SMe2（X = H、Cl、Br）、BF3·OEt2 和 BCl3 的反应生成路易斯加合物 [BICAAC·BH3]（1）、[BICAAC·BHCl2]（2）、[BICAAC·BH2Cl]（3）、[BICAAC·BF3]（4）、[BICAAC·BCl3]（5）和[BICAAC·BBr3]（6），而更具氢化物的硼烷 9-硼双环[3.3.1]壬烷（9-BBN）和邻苯二酚硼烷（HBcat）则使碳烯碳插入 B-H 键中，形成[BICAAC（H）-（9-BBN）]（7）和[BICAAC（H）-Bcat]（8）。这些配合物是 BICAAC-硼化合物的第一个例子，并通过红外光谱、多核 NMR 光谱、高分辨率质谱和单晶 X 射线衍射进行了表征。还进行了计算分析，以深入了解 B-H 键活化和加合物形成的机理。此外，还比较了 BICAAC 与硼烷的反应与已知的 CAACs 和 NHCs 的反应。
