Ligand self-recognition in the stereoselective assembly of [2 + 2] metallomacrocycles from racemic chiral bisbipyridyl molecular clefts and zinc(ii)
作者:Pia I. Anderberg、Jennifer J. Turner、Krystal J. Evans、Lauren M. Hutchins、Margaret M. Harding
DOI:10.1039/b404054f
日期:——
The synthesis of racemic and optically pure ligand L, in which two 6,6'-disubstituted bipyridines are connected by methyleneoxy linkers to the molecular cleft dibenzobicyclo[b,f][3.3.1]nona-5a,6a-diene-6,12-dione, is reported. In the presence of 2 equivalents of zinc(ii) trifluoromethansulfonate (+/-)- undergoes slow reversible coordination over 24 h to form a pair of enantiomeric [2 + 2] metallomacrocycles
外消旋和光学纯的配体L的合成,其中两个6,6'-二取代的联吡啶通过亚甲基氧基连接到分子裂隙二苯并双环[b,f] [3.3.1] nona-5a,6a-diene-6,据报道有十二二酮。在存在2当量的三氟甲磺酸锌(+/-)-(+/-)-的过程中,经过24小时缓慢可逆配位,形成一对对映体[2 + 2]金属大环化合物[Zn2(+)L2](OTf)(4 )和[Zn2(-)L2](OTf)(4),分别包含两个(+)-L配体或两个(-)-L配体。通过(+)-L或(-)-L形成了相同的复合物但以显着更快的速度(3 h)进行的独立研究证实了这一分配,[Zn2(+)L2](OTf )(4)和[Zn2(-)L2](OTf)(4)给出强度相同但符号相反的信号。用铜(I)处理(+/-)-L或旋光纯L时,表明迅速形成了低聚物以及[2 + 2]金属大环化合物的混合物。复杂的Zn2L2(OTf)(4)在室温下在NMR时