Imidazolium-based macrocycles as multisignaling chemosensors for anions.
A series of structurally novel anion receptors , , and in which a ferrocene unit and a fluorescent moiety are linked to two imidazolium rings have been designed and prepared from 1,1'-bis(imidazolylmethyl)ferrocene. Their crystal structures revealed that these receptors are capable of incorporating anions such as PF(6)(-) and Br(-). Consequently, the anion binding studies were carried out using various techniques including electrochemistry (CV and OSWV), fluorescence, UV-vis, and (1)H NMR spectroscopy. All the receptors showed a special electrochemical response to the F(-) anion with a remarkable cathodic shift of more than 260 mV and displayed a unique selectivity for F(-) and AcO(-) anions with fluorescence enhancement over various other anions of present interest (Cl(-), Br(-), I(-), HSO(4)(-), H(2)PO(4)(-)). In addition, for receptor , obvious absorption changes were observed when the H(2)PO(4)(-) anion was added while other anions (F(-), Cl(-), Br(-), I(-), AcO(-), HSO(4)(-)) showed only a minor influence on the UV-vis spectra. (1)H NMR titrations demonstrated that receptors and can bind anions through (C-H)(+)X(-) hydrogen bonds and showed strong affinity and high selectivity for the AcO(-) anion in acetonitrile.
Niu
Hao-Tao
HT
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China.
Yin
Zhenming
Z
Su
Dongdong
D
Niu
Dong
D
He
Jiaqi
J
Cheng
Jin-Pei
JP
D000838:Anions / Q000737:chemistry; D000873:Anthracenes / Q000737:chemistry; D001665:Binding Sites; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D005453:Fluorescence; D007093:Imidazoles / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D000075163:Metallocenes; D009281:Naphthalenes / Q000737:chemistry; D011810:Quinoxalines / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D017186:Titrimetry
D000838:Anions; D000873:Anthracenes; D005296:Ferrous Compounds; D007093:Imidazoles; D047028:Macrocyclic Compounds; D000075163:Metallocenes; D009281:Naphthalenes; D011810:Quinoxalines; C031721:naphthalene; C034020:anthracene; C004998:ferrocene