title: Aniline-containing guests recognized by α,α',δ,δ'-tetramethyl-cucurbit[6]uril host.
abstract: The host-guest complexation of symmetrical α,α',δ,δ'-tetramethyl-cucurbit[6]uril (TMeQ[6]) and cucurbit[7]uril (Q[7]) with a series of aniline-containing guests has been investigated by various experimental techniques including NMR, ITC, and X-ray crystallography. Experimental results indicate that both TMeQ[6] and Q[7] hosts can encapsulate aniline-containing guests to form stable inclusion complexes. However, the oval cavity of TMeQ[6] is more complementary in size and shape to the aromatic ring of the guests than the spherical cavity of Q[7]. Shielding and deshielding effects of the aromatic ring on guests lead to the remarkable chemical shifts of the TMeQ[6] host protons. The rotational restriction of the guests in the oval cavity of TMeQ[6] results in the large negative values of entropy. The X-ray crystal structure of the 1:1 inclusion complex between TMeQ[6] and N,N'-diethyl-benzene-1,4-diamine unambiguously reveals that the aromatic ring of the guest resides in the oval cavity of TMeQ[6].
authors.affiliation: College of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002, China.
authors.forename: Rui-Lian
authors.initials: RL
authors.lastname: Lin
authors.affiliation: College of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002, China.
authors.forename: Guo-Sheng
authors.initials: GS
authors.lastname: Fang
authors.affiliation: College of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002, China.
authors.forename: Wen-Qi
authors.initials: WQ
authors.lastname: Sun
authors.affiliation: College of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002, China.
authors.forename: Jing-Xin
authors.initials: JX
authors.lastname: Liu