Department of Chemistry, University of California - Riverside, Riverside, CA 92521, USA.
Dalton Trans. 2022 Jul 26;51(29):10920-10929. doi: 10.1039/d2dt01451c.
Self-assembled FeL cage complexes with variable internal functions can be synthesized from a 2,7-dibromocarbazole ligand scaffold, which orients six functional groups to the cage interior. Both ethylthiomethylether and ethyldimethylamino groups can be incorporated. The cages show strong ligand-centered fluorescence emission and a broad range of guest binding properties. Coencapsulation of neutral organic guests is favored in the larger, unfunctionalized cage cavity, whereas the thioether cage has a more sterically hindered cavity that favors 1 : 1 guest binding. Binding affinities up to 10 M in CHCN are seen. The dimethylamino cage is more complex, as the internal amines display partial protonation and can be deprotonated by amine bases. This amine cage displays affinity for a broad range of neutral organic substrates, with affinities and stoichiometries comparable to that of the similarly sized thioether cage. These species show that simple variations in ligand backbone allow variations in the number and type of functions that can be displayed towards the cavity of self-assembled hosts, which will have applications in biomimetic sensing, catalysis and molecular recognition.
具有可变内部功能的自组装 FeL 笼配合物可以从 2,7-二溴咔唑配体支架合成，该支架将六个功能基团定向到笼内。既可以掺入乙基硫代甲醚基团，也可以掺入乙基亚氨基二甲基基团。这些笼显示出强烈的配体中心荧光发射和广泛的客体结合特性。在较大的非功能化笼腔中有利于中性有机客体的共包封，而硫醚笼具有更具空间位阻的腔，有利于 1:1 客体结合。在 CHCN 中观察到高达 10 M 的结合亲和力。二甲氨基笼更加复杂，因为内部胺基显示部分质子化，可以被胺碱去质子化。这种胺笼对广泛的中性有机底物表现出亲和力，其亲和力和化学计量与类似大小的硫醚笼相当。这些物种表明，配体骨架的简单变化允许在自组装主体的腔中显示出数量和类型的功能变化，这将在仿生传感、催化和分子识别等方面有应用。
