Synthesis,Coordination Behavior,and Reduction Chemistry of Cymantrenyl‐1,3‐bis(2,3,4,5‐tetraphenyl)borole |
| |
| Authors: | Prof?Dr Holger Braunschweig Alexander Damme Dr Daniela Gamon Hauke Kelch Dr Ivo Krummenacher Dr Thomas Kupfer Dr Krzysztof Radacki |
| |
| Institution: | Institut für Anorganische Chemie, Julius–Maximilians Universit?t Würzburg, Am Hubland, 97074 Würzburg (Germany), Fax: (+49)?931‐31‐84623 |
| |
| Abstract: | We describe the synthesis of base‐free bisborole Cym?(BC4Ph4)2]—Cym?=(OC)3Mn(η5‐C5H3)—and its transformation into two fully characterized Lewis acid–base adducts with pyridine bases of the type 4‐R? NC5H4 (R=tBu, NMe2). The results of electrochemical, as well as NMR and UV/Vis spectroscopic studies on Cym?(BC4Ph4)2] and the related monoborole derivative Cym(BC4Ph4)]—Cym=(OC)3Mn(η5‐C5H4)—provided conclusive evidence for 1) the enhanced Lewis acidity of the two boron centers that result from conjugation of two borole fragments, and 2) the fact that Mn? B bonding interactions between the Lewis acidic borole moieties and the Mn center are considerably less pronounced for bisborole Cym?(BC4Ph4)2]. In addition, the reduction chemistry of Cym?(BC4Ph4)2] has been studied in detail, both electrochemically and chemically. Accordingly, chemical reduction of Cym?(BC4Ph4)2] with magnesium anthracene afforded the corresponding tetraanion, which features a rare Mg? OC bonding mode in the solid state. |
| |
| Keywords: | aromaticity boroles cymantrene electrochemistry reduction |
|
|
