Metal–Organic Rotaxane Frameworks Assembly by Cucurbit[6]uril-Based Pseudorotaxanes and Mixed Ligands

Four novel high-dimensional metal–organic rotaxane frameworks (MORFs) were successfully fabricated by cucurbit[6]­uril-based pseudorotaxanes ([PR43]) and rigid carboxylate ligands by adjusting the synthesis temperature and the length of ligands. Compound 1 represents a three periodic 2-fold interpenetrating dia network based on a binuclear {Cd2Cl4O4} second building unit (SBU). 2 and 3 are isostructural pcu networks constructed by binuclear and trinuclear cadmium clusters, respectively, while compound 4 is a two-dimensional layered network with a large grid 44.3 × 19.8 Å2. Furthermore, their fluorescent properties in different solvents are investigated.本研究以基于葫芦[6]脲（cucurbit[6]uril）的准轮烷（pseudorotaxanes，[PR43]）与刚性羧酸配体为构筑基元，通过调控合成温度与配体长度，成功制备得到四种新型高维金属有机轮烷骨架（metal–organic rotaxane frameworks，MORFs）。化合物1以双核{Cd₂Cl₄O₄}次级结构单元（second building unit，SBU）为构筑节点，构筑得到三维周期性二重穿插dia拓扑网络。化合物2与3分别以双核镉簇、三核镉簇为构筑节点，形成同构的pcu拓扑网络。而化合物4为二维层状网络，其网格尺寸达44.3 × 19.8 Ų。此外，本文还考察了这四种化合物在不同溶剂中的荧光性能。