Cation‐Controlled Formation and Interconversion of the
<i>fac</i>
/
<i>fac</i>
and
<i>mer</i>
/
<i>mer</i>
Stereoisomers of a Triple‐Stranded Helicate
作者:Xiaofei Chen、Christian Mevissen、Saskia Huda、Christian Göb、Iris M. Oppel、Markus Albrecht
DOI:10.1002/anie.201904181
日期:2019.9.9
biscatecholester ligands with oligoether spacers were used to prepare dinuclear titanium(IV) triscatecholate based helicates. In the case of Li4 [(1/2)3 Ti2 ], "classical" helicates with three internally bound Li+ ions and syn-oriented ligands in the complex units (fac/fac isomer) were obtained. In the case of the sodium salt Na4 [(2)3 Ti2 ], a different homochiral dinuclear triple-stranded helicate with two
具有低醚间隔基的两个双儿茶酚酯配体被用于制备基于三儿茶酚酸酯的双核钛(IV)螺旋。在Li4 [(1/2)3 Ti2]的情况下,获得了在复合单元(fac / fac异构体)中具有三个内部结合的Li +离子和顺取向配体的“经典”螺旋。在钠盐Na4 [(2)3 Ti2]的情况下,形成了带有两个内部结合的Na +离子的不同的同手性双核三链螺旋体。复杂单元是反构型的,并且两个配体间隔基在内部与螺旋的外部位置连接(mer / mer异构体)。钠离子的去除和锂离子的添加导致从一种拓扑切换为另一种,并以扩展的螺旋[[2)3 Ti2] 4-作为中间体。切换回“非经典”