Effects of anions on the structural regulation of Zn‑salen‑modified metal‑organic cage  

基于阴离子的Zn‑salen修饰金属-有机笼的构型调控

作　　者：GUO Qiaojia CAI Junkai DUAN Chunying 郭乔佳;蔡俊凯;段春迎(大连理工大学精细化工国家重点实验室,大连116024)

机构地区：[1]State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian,Liaoning 116024,China

出　　处：《无机化学学报》2024年第11期2203-2211,共9页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.92361201,22201129);江苏省自然科学基金(No.BK20220033)资助。

摘　　要：By virtue of a 3∶1 complementary coordination strategy,a chiral heteroleptic metal-organic cage that con-tains divergent functional units,Pd‑R(Zn),was precisely constructed via self-assembly of monodentate variational Zn-salen ligands RZn and NADH(reduced nicotinamide adenine dinucleotide)mimic modified tridentate ligands with square-planar Pd ions.UV-Vis and luminescence spectra experiments reveal that different anions could selec-tively interact with different sites of Zn-salen modified metal-organic cages to achieve the structural regulation of cage compound,by using the differentiated host-guest electrostatic interactions of counter ions with metal-organic hosts.Compared to other anions,the presence of chloride ions caused the most significant fluorescence emission enhancement of Pd‑R(Zn),meanwhile,the UV-Vis absorption band attributed to the salen aromatic backbone showed an absorption decrease,and the metal-to-ligand induced peak displayed a blue shift effect.Circular dichro-ism and ^(1)H NMR spectra further demonstrate that the introduction of chloride anions is beneficial to keeping a more rigid scaffold.选择具有构型可变的手性前体Zn-salen修饰的单齿配体RZn,与辅酶NADH(还原型烟酰胺腺嘌呤二核苷酸)修饰的三齿配体通过3:1互补组装策略与方形平面配位的Pd(Ⅱ)自组装,实现了混合不同功能配体的手性金属-有机笼Pd-R(Zn)的定向可控构筑。紫外可见光谱和荧光光谱表明,利用对离子与金属-有机主体差异化的主客体静电相互作用,不同阴离子能够选择性作用于Zn-salen修饰金属-有机笼的不同位点,进而实现笼状化合物的构型调控。相比于其他阴离子,氯离子使Pd-R(Zn)的荧光发射增强效应最为显著,同时紫外可见吸收光谱中归属于salen骨架共轭的吸收带降低,且金属至配体电荷转移吸收带发生蓝移。圆二色谱和核磁共振氢谱进一步表明,氯离子的引入有利于产生更刚性的骨架结构。

关 键 词：metal-organic cage Zn-salen host-guest electrostatic interaction ANIONS structural regulation 

分 类 号：O614.241[理学—无机化学]