Electroactive Thiazole Derivatives Capped with Ferrocenyl Units Showing Charge-Transfer Transition and Selective Ion-Sensing Properties: A Combined Experimental and Theoretical Study
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- 作者：Antonio Caballero ; Vega Lloveras ; David Curiel ; Alberto Tá ; rraga ; Arturo Espinosa ; Rafaela Garcí ; a ; José ; Vidal-Gancedo ; Concepció ; Rovira ; Klaus Wurst ; Pedro Molina ; Jaume Veci
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：February 5, 2007
- 年：2007
- 卷：46
- 期：3
- 页码：825 - 838
- 全文大小：363K
- 年卷期：v.46,no.3(February 5, 2007)
- ISSN：1520-510X
文摘
The synthesis, optical and electrochemical properties, and X-ray characterization of two thiazole derivatives cappedby ferrocenyl groups (5 and 7) and their model compounds with one ferrocenyl, either at 2 or 5 position of themono- or bis-thiazolyl rings (3, 9, 11, and 14), are presented. Bisferrocenyl thiazole 5 forms the mixed-valencespecies 5
+ by partial oxidation which, interestingly, shows an intramolecular electron-transfer phenomenon. Moreover,the reported heteroaromatic compounds show selective ion-sensing properties. Thus, ferrocenylthiazoles linkedacross the 5 position of the heteroaromatic ring are selective chemosensors for Hg2+ and Pb2+ metal ions;5-ferrocenylthiazole 3 operates through two channels, optical and redox, for Hg2+ and only optical for Pb2+, whereas1,1'-bis(thiazolyl)ferrocene 14 is only an optical sensor for both metal ions. Moreover, complex 3 behaves as anelectrochemically induced switchable chemosensor because of the low metal-ion affinity of the oxidized 3+ species.On the other hand, ferrocenylthiazole 9, in which the heterocyclic ring and the ferrocene group are linked acrossthe 2 position, is a selective redox sensor for Hg2+ metal ions, and it responds optically, as does bis(thiazolyl)ferrocene 11, to a narrow range of cations (Zn2+, Cd2+, Hg2+, Ni2+, and Pb2+). Finally, bis(ferrocenyl)thiazole 5 isa dual optical and redox sensor for Zn2+, Cd2+, Hg2+, Ni2+, and Pb2+, whereas bis(ferrocenyl) compound 7, bearinga bis(thiazole) unit as a bridge, is only a chromogenic sensor for Zn2+, Cd2+, Hg2+, Ni2+, and Pb2+. The experimentaldata and conclusions about both the electronic and ion-sensing properties are supported by DFT calculationswhich show, in addition, an unprecedented intramolecular electron-transfer reorganization after the first one-electronoxidation of compound 5.
+ by partial oxidation which, interestingly, shows an intramolecular electron-transfer phenomenon. Moreover,the reported heteroaromatic compounds show selective ion-sensing properties. Thus, ferrocenylthiazoles linkedacross the 5 position of the heteroaromatic ring are selective chemosensors for Hg2+ and Pb2+ metal ions;5-ferrocenylthiazole 3 operates through two channels, optical and redox, for Hg2+ and only optical for Pb2+, whereas1,1'-bis(thiazolyl)ferrocene 14 is only an optical sensor for both metal ions. Moreover, complex 3 behaves as anelectrochemically induced switchable chemosensor because of the low metal-ion affinity of the oxidized 3+ species.On the other hand, ferrocenylthiazole 9, in which the heterocyclic ring and the ferrocene group are linked acrossthe 2 position, is a selective redox sensor for Hg2+ metal ions, and it responds optically, as does bis(thiazolyl)ferrocene 11, to a narrow range of cations (Zn2+, Cd2+, Hg2+, Ni2+, and Pb2+). Finally, bis(ferrocenyl)thiazole 5 isa dual optical and redox sensor for Zn2+, Cd2+, Hg2+, Ni2+, and Pb2+, whereas bis(ferrocenyl) compound 7, bearinga bis(thiazole) unit as a bridge, is only a chromogenic sensor for Zn2+, Cd2+, Hg2+, Ni2+, and Pb2+. The experimentaldata and conclusions about both the electronic and ion-sensing properties are supported by DFT calculationswhich show, in addition, an unprecedented intramolecular electron-transfer reorganization after the first one-electronoxidation of compound 5.