2,7-萘二磺酸阴离子导向五元瓜环基超分子自组装体的制备及其荧光检测性能

Synthesis and fluorescence sensing properties of cucurbit[5]uril-based supramolecular self-assemblies incorporating naphthalene-2,7-disulphonate as the structure⁃directing agent

通过引入2,7-萘二磺酸(2,7-NDA2-)阴离子作为结构导向剂,与五元瓜环(Q[5])和过渡金属离子(Co^(2+)、Ni^(2+)、Zn^(2+)、Cd^(2+))在水热条件下制备了4种新颖的Q[5]基超分子自组装体(Q[5]-SA),即{[M(H_(2)O)4(Q[5])]·(NDA)}·x H_(2)O(M=Co (1)、Ni (2)、Zn (3))和{[Cd2Cl2(H_(2)O)4(Q[5])]·(NDA)}·13H_(2)O (4)。单晶X射线衍射测试结果表明,自组装体1~3同构,其中Q[5]仅一端的部分端口羰基氧原子与金属离子配位形成简单配合物;而4中Q[5]的2个端口均与金属离子Cd^(2+)配位形成了一维配位链。在自组装体1~4中,配体2,7-H_(2)NDA均全脱质子,形成2,7-NDA2-阴离子平衡体系电荷,但均未能与金属离子配位,而在2,7-NDA2-阴离子与Q[5]外壁之间的瓜环外壁作用下进一步形成三维超分子结构。此外,还研究了自组装体1和4的荧光传感性能,结果表明它们都能够作为抗生素诺氟沙星(NFX)的比率型荧光探针。

Four new cucurbit[5]uril‑based(Q[5])supramolecular self‑assemblies(Q[5]‑SA),namely{[M(H_(2)O)4(Q[5])]·(NDA)}·xH_(2)O(M=Co(1),Ni(2),Zn(3))and{[Cd2Cl2(H_(2)O)4(Q[5])]·(NDA)}·13H_(2)O(4),were synthesized by employing naphthalene‑2,7‑disulphonate anion(2,7‑NDA2-)as the structure‑directing agent to react with Q[5]and transition metal cations(Co^(2+),Ni^(2+),Zn^(2+),Cd^(2+))under hydrothermal conditions.Single‑crystal X‑ray diffraction(SC‑XRD)results reveal that self‑assemblies 1‑3 are isostructural and the metal cations(Co^(2+),Ni^(2+),Zn^(2+))merely coordinate with the carbonyl groups from one portal of Q[5]to form simple coordination compounds,while the Cd^(2+)cation in selfassembly 4 is bound to both of the two portals of Q[5]to generate 1D coordination chains.In particular,the 2,7‑NDA2-ligands in all self‑assemblies are deprotonated to form organic anions 2,7‑NDA2-,which balanced the system charge.However,2,7‑NDA2-fails to coordinate with the metal ions coordinated with Q[5],and these Q[5]‑based coordination compounds are assembled into 3D supramolecular architectures through outer surface interactions of Q[5].Furthermore,the fluorescence sensing properties of 1 and 4 were investigated and the results indicated that they could both function as ratiometric fluorescence sensors for norfloxacin(NFX).