Guest releasing from solution to solid-state triggered by cyclomaltohexaose (α-cyclodextrin) aggregation.
Supramolecuar aggregations 1 and 2 were prepared by complexing cyclomaltohexaose with two azodipyridine isomers: 4,4'-azodipyridine and 2,2'-azodipyridine, and their binding abilities and assembly behaviors were investigated comprehensively by X-ray crystallography, 2D NMR spectroscopy, and isothermal titration calorimetry. In solution, 1:1 host-guest complexation is generally assumed, whereas in the solid state, a 2:1 stoichiometry is observed. Crystal structures reveal that channel-type aggregation exists in complex 1, while a layer-type manner is the dominant packing mode in complex 2. The disparity of nitrogen atom position leads to the different binding modes and further affects the aggregation types in complexes 1 and 2.
Gu
Zhuo-Yi
ZY
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, PR China.
Guo
Dong-Sheng
DS
Liu
Yu
Y
D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D012996:Solutions; D047391:alpha-Cyclodextrins / Q000737:chemistry*
D012996:Solutions; D047391:alpha-Cyclodextrins; C032613:alpha-cyclodextrin