Syntheses, structures, luminescence and electrochemistry of benzene- and biphenyl-centered bis- and tris-1,3,2-diazaboroles and -1,3,2-diazaborolidines
作者:Lothar Weber、Imme Domke、Christian Schmidt、Thomas Braun、Hans-Georg Stammler、Beate Neumann
DOI:10.1039/b514920g
日期:——
Reaction of 1,4-bis(dibromoboryl)benzene (1a) with 2 equiv. of the diazabutadiene tBuNCH–CHNtBu and subsequent reduction of the obtained bis(1,3,2-diazaborolium)salt 2a with sodium amalgam afforded the 1,4-bis(1,3,2-diazaborolyl)benzene 3a. Similary, 1,3-bis(dibromoboryl)benzene (1b), 1,3,5-tris(dibromoboryl)benzene (1c) and 4,4′-bis(dibromoboryl)biphenyl (1d) were converted into compounds 3b, 3c and 3d which contain two or three diazaborolyl substituents at the arene core. Treatment of precursors 1a,b,d with two equiv. or 1c with three equiv. of N,N′-di-tert-butylethane-1,2-diamine in the presence of an excess of NEt3 gave rise to the diazaborolidine derivatives 4a–4d. Reaction of 1,3-bis(diiodoboryl)benzene 1e with two equivalents of N,N′-dimethylethane-1,2-diamine in the presence of NEt3 furnished the corresponding 1,3-bis(diazaborolidinyl)benzene 4e. The novel compounds were characterized by elemental analyses and spectroscopy (1H, 13C, 11B NMR, MS). The molecular structures of 3c, 4a and 4e were eludicated by X-ray-diffraction analyses. In addition to this, the oxidative cyclovoltammograms and blue emission spectra of these novel compounds were discussed. Here, the electronic communication between boron heterocycles on the different spacer-units and the luminescence of the oligo-diazaborolylarenes were of interest.
将 1,4-双(二溴硼酰)苯 (1a) 与 2 等量的重氮丁二烯 tBuNCH-CHNtBu 反应,然后用钠汞齐还原得到的双(1,3,2-二氮硼鎓)盐 2a,得到 1,4-双(1,3,2-二氮硼酰)苯 3a。同样,1,3-双(二溴硼酰基)苯 (1b)、1,3,5-三(二溴硼酰基)苯 (1c) 和 4,4′-双(二溴硼酰基)联苯 (1d) 被转化为化合物 3b、3c 和 3d,这些化合物在炔芯上含有两个或三个重氮硼酰基取代基。在过量 NEt3 的存在下,用两个等量的 N,N′-二叔丁基乙烷-1,2-二胺处理前体 1a,b,d,或用三个等量的 N,N′-二叔丁基乙烷-1,2-二胺处理前体 1c,可得到重氮硼烷衍生物 4a-4d。在 NEt3 存在下,1,3-双(二碘丁酰基)苯 1e 与两个当量的 N,N′-二甲基乙烷-1,2-二胺反应,生成相应的 1,3-双(重氮硼烷基)苯 4e。这些新型化合物通过元素分析和光谱(1H、13C、11B NMR、MS)进行了表征。通过 X 射线衍射分析,确定了 3c、4a 和 4e 的分子结构。此外,还讨论了这些新型化合物的氧化环形伏安图和蓝色发射光谱。在这里,不同间隔单元上的硼杂环之间的电子通信以及低聚二氮杂硼戊二烯的发光特性引起了人们的兴趣。