Syntheses and Structures of Hypervalent Pentacoordinate Carbon and Boron Compounds Bearing an Anthracene Skeleton − Elucidation of Hypervalent Interaction Based on X-ray Analysis and DFT Calculation
oxygen-donating anthracene skeleton had a trigonal bipyramidal (TBP) pentacoordinate structure with relatively long apical distances (ca. 2.38-2.46 A). Despite the relatively long apical distances, DFT calculation of carbon species 27 and boron species 56 and experimental accurate X-ray electron density distribution analysis of 56 supported the existence of the apical hypervalent bond even though the nature of
使用四种新合成的三齿配体前体合成了在 1,8 位带有两个氧或氮原子的蒽骨架的五配位和四配位碳和硼化合物 (27, 38, 50-52, 56-61)。通过 X 射线晶体学分析表征了几种碳和硼化合物,表明带有供氧蒽骨架的化合物 27、56-59 具有三角双锥 (TBP) 五配位结构,具有相对较长的顶端距离(约 2.38-2.46 A )。尽管根尖距离相对较长,碳物质 27 和硼物质 56 的 DFT 计算和 56 的实验精确 X 射线电子密度分布分析支持顶端高价键的存在,即使中心碳(或硼)和供体氧之间的高价相互作用的性质原子相对较弱且具有离子性。另一方面,带有供氮蒽骨架的化合物 50-52 的 X 射线分析显示不对称的四配位碳或硼原子仅由两个供氮基团中的一个配位。有趣的是,由于具有供氧骨架,在中心硼原子上具有两个氯原子的化合物 61 显示出四配位结构,尽管具有两个氟原子的相应化合物 60 显示出五配位结构。
Reactivity of Lewis Acid Activated Diaza- and Dithiaboroles in Electrophilic Arene Borylation
作者:S. A. Solomon、A. Del Grosso、E. R. Clark、V. Bagutski、J. J. W. McDouall、M. J. Ingleson
DOI:10.1021/om201228e
日期:2012.3.12
3,2-benzodithiaborole ((CatS2)BCl) are active for arene borylation, displaying reactivity between that of catecholato- and dichloro-boron electrophiles. [(CatS2)B(NEt3)][AlCl4] is significantly less prone to nucleophile-induced transfer of halide from [AlCl4]¯ to boron compared to catecholato and dichloro borocations, enabling it to borylate arenes containing nucleophilic −NMe2 moieties in high conversion