title: Mixed behavior of p-phenylenediaminium guest binding with the inverted cucurbit[6]uril host.
abstract: The binding interaction between inverted cucurbit[6]uril (iQ[6]) and p-phenylenediaminium both in the solid state and in aqueous solution has been investigated by X-ray crystallography, (1)H NMR spectroscopy and isothermal titration calorimetry (ITC). The experimental results suggest that the binding interaction between iQ[6] and p-phenylenediaminium may generate two different types of complexes in the solid state: one is an inclusion structure and the other is a sandwich structure. In aqueous solution, the iQ[6] host has an ability to accommodate the p-phenylenediaminium guest and in-out guest exchange is fast on the NMR time scale. ITC data indicate that the complexation of iQ[6] with p-phenylenediaminium is entropy driven.
authors.affiliation: Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China. gzutao@263.net.
authors.forename: De-Qing
authors.initials: DQ
authors.lastname: Zhang
authors.forename: Rui-Lian
authors.initials: RL
authors.lastname: Lin
authors.forename: Wen-Qi
authors.initials: WQ
authors.lastname: Sun
authors.forename: Zhu
authors.initials: Z
authors.lastname: Tao
authors.forename: Qian-Jian
authors.initials: QJ
authors.lastname: Zhu
authors.forename: Jing-Xin
authors.initials: JX
authors.lastname: Liu
mesh_terms: D000588:Amines / Q000737:chemistry*; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007093:Imidazoles / Q000737:chemistry*; D008968:Molecular Conformation; D010655:Phenylenediamines / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D012996:Solutions; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D000588:Amines; D001952:Bridged-Ring Compounds; D007093:Imidazoles; D010655:Phenylenediamines; D012996:Solutions; C454805:cucurbit(6)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils; C029728:4-phenylenediamine