University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269-3060, USA.
Dalton Trans. 2012 Jul 14;41(26):8162-74. doi: 10.1039/c2dt30135k. Epub 2012 Apr 10.
Two generations of nitrobenzhydrol-based photocages for Zn(2+) have been prepared and characterized. The first series includes the tridentate ZinCast-1 utilizes a bis-pyridin-2-ylmethyl-aniline ligand that forms a 5,5-chelate ring upon metal binding. The related photocages ZinCast-2 with a N-[2-(pyridine-2-yl)ethyl]-N-(pyridine-2-ylmethyl)aniline (5,6-chelate ring) and ZinCast-3 with a N,N-bis[2-(pyridine-2-yl)ethyl]aniline (6,6-chelate ring) were synthesized for comparative studies. The complexes formed by the ions Cu(2+), Zn(2+) and Cd(2+) with three ZinCast and their photoproducts (ZinUnc) were interrogated by UV-Vis spectroscopy. The studies indicate that ZinCast-1 forms complexes of the highest stability and ZinCast-3 exhibits the most significant changes in metal affinity upon uncaging. These results suggest that the changes in nitrogen atom donor ability as well as the initial complex stability must be considered to design a photocage with the desired properties. The composite results were used to design ZinCast-4 and ZinCast-5, the second generation photocages that incorporate an additional adjacent ether ligand into the Zn(2+) chelator.
两代基于硝基苯并氢醇的锌（Ⅱ）光笼试剂已经被制备并进行了表征。第一系列包括三齿的 ZinCast-1，它利用双吡啶-2-基甲基苯胺配体，在金属结合时形成 5,5 螯合环。相关的光笼试剂 ZinCast-2 具有 N-[2-(吡啶-2-基)乙基]-N-(吡啶-2-基甲基)苯胺（5,6-螯合环）和 ZinCast-3 具有 N,N-双[2-(吡啶-2-基)乙基]苯胺（6,6-螯合环），用于比较研究。用三种 ZinCast 与铜（Ⅱ）、锌（Ⅱ）和镉（Ⅱ）离子形成的配合物及其光解产物（ZinUnc）通过紫外可见光谱进行了研究。研究表明，ZinCast-1 形成了最高稳定性的配合物，而 ZinCast-3 在去笼时表现出对金属亲和力的最大变化。这些结果表明，在设计具有所需性质的光笼时，必须考虑氮原子供体能力的变化以及初始配合物的稳定性。综合结果用于设计第二代光笼试剂 ZinCast-4 和 ZinCast-5，它们在锌（Ⅱ）螯合剂中引入了一个额外的相邻醚配体。
