Generation of Dicoordinate Boron(I) Units by Fragmentation of a Tetra-Boron(I) Molecular Square
Generation of Dicoordinate Boron(I) Units by Fragmentation of a Tetra-Boron(I) Molecular Square
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DOI：
10.1002/anie.201608429
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发表时间：
2016-11-07
影响因子：
16.6
通讯作者：
Krummenacher, Ivo
中科院分区：
文献类型：
--
作者：
Arrowsmith, Merle;Auerhammer, Dominic;Krummenacher, Ivo
卡宾-硼烷加合物[（cAAC）BBr 2-（CN）]（cAAC= 1-（2，6-二异丙基苯基）-3，3，5，5-四甲基吡咯烷-2-亚基）的还原干净地产生四（氰基硼）物种[（cAAC）B（CN）]（4），其呈现12元（BCN）（4）环。Kohn-Sham分子轨道分析表明B-I原子具有明显的硼烯特征。发现[（cAAC）B（CN）]（4）还原每个硼中心两当量的AgCN以产生[（cAAC）B（CN）（3）]，并在与IMeMe（1，3，4，5-四甲基咪唑-2-亚基）反应时断裂成二配位硼（I）单元以产生相应的三配位混合cAAC-NHC氰基硼烯。通过在过量膦存在下还原[（cAAC）BBr 2（CN）]获得类似的cAAC-膦氰基硼烯。
Reduction of carbene-borane adduct [(cAAC) BBr2-(CN)] (cAAC= 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin- 2-ylidene) cleanly yielded the tetra(cyanoborylene) species [(cAAC)B(CN)](4) presenting a 12-membered (BCN)(4) ring. The analysis of the Kohn-Sham molecular orbitals showed significant borylene character of the B-I atoms. [(cAAC)B(CN)](4) was found to reduce two equivalents of AgCN per boron center to yield [(cAAC)B(CN)(3)] and fragmented into two-coordinate boron(I) units upon reaction with IMeMe (1,3,4,5-tetramethylimidazol-2-ylidene) to yield the corresponding tricoordinate mixed cAAC-NHC cyanoborylene. The analogous cAAC-phosphine cyanoborylene was obtained by reduction of [(cAAC)BBr2(CN)] in the presence of excess phosphine.