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Journal ArticleDOI

Colorimetric “Naked Eye” Sensing of Anions in Aqueous Solution

19 Nov 2005-Journal of Organic Chemistry (American Chemical Society)-Vol. 70, Iss: 26, pp 10875-10878
TL;DR: The synthesis and UV-vis and NMR spectroscopic studies of thiourea-based colorimetric sensors for anions are presented, showing that these sensors can recognize anions through hydrogen binding even in competitive pH-buffered aqueous solutions.
Abstract: The synthesis and UV−vis and NMR spectroscopic studies of thiourea-based colorimetric sensors for anions are presented. These sensors can recognize anions through hydrogen binding even in competitive pH-buffered aqueous solutions, giving rise to large color changes that are clearly visible to the naked eye.
Citations
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Journal ArticleDOI
TL;DR: In this article, a review article focuses primarily on the work carried in our laboratories over the last few years using luminescent and colorimetric sensors, where the anion recognition occurs through hydrogen bonding in organic or aqueous solvents.

1,165 citations

Journal ArticleDOI
TL;DR: This critical review focuses on the development of anion sensors, being either fluorescent and/or colorimetric, based on the use of the 1,8-naphthalimide structure; a highly versatile building unit that absorbs and emits at long wavelengths.
Abstract: This critical review focuses on the development of anion sensors, being either fluorescent and/or colorimetric, based on the use of the 1,8-naphthalimide structure; a highly versatile building unit that absorbs and emits at long wavelengths. The review commences with a short description of the most commonly used design principles employed in chemosensors, followed by a discussion on the photophysical properties of the 4-amino-1,8-naphthalimide structure which has been most commonly employed in both cation and anion sensing to date. This is followed by a review of the current state of the art in naphthalimide-based anion sensing, where systems using ureas, thioureas and amides as hydrogen-bonding receptors, as well as charged receptors have been used for anion sensing in both organic and aqueous solutions, or within various polymeric networks, such as hydrogels. The review concludes with some current and future perspectives including the use of the naphthalimides for sensing small biomolecules, such as amino acids, as well as probes for incorporation and binding to proteins; and for the recognition/sensing of polyanions such as DNA, and their potential use as novel therapeutic and diagnostic agents (95 references).

1,059 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the stability of the 1:1 complexes is strictly related to the acidic tendencies of the receptor and to the basic properties of the anion.
Abstract: Molecules containing polarized N−H fragments behave as H-bond donors toward anions and are widely used as receptors for recognition and sensing purposes in aprotic solvents (CHCl3, MeCN, and DMSO). We present examples of receptors containing pyrrole and urea subunits, and we discuss the stability of their H-bond complexes with a variety of anions. It is demonstrated that the stability of the 1:1 complexes is strictly related to the acidic tendencies of the receptor and to the basic properties of the anion. It may happen also that more basic anions induce the deprotonation of the receptor, if equipped with electron-withdrawing substituents. This is typically observed on interaction with fluoride, due to the formation of the very stable [HF2]- self-complex. For urea-based receptors armed with chromogenic substituents, the addition of a large excess of the anion (F-, OH-) may induce the consecutive deprotonation of both N−H fragments, processes signaled by the development of vivid colors.

739 citations

Journal ArticleDOI
TL;DR: This critical review covers advances in anion complexation chemistry related to receptors based on organic frameworks in the years 2005-2006 and includes a discussion of anion templated assembly.
Abstract: This critical review covers advances in anion complexation chemistry related to receptors based on organic frameworks in the years 2005–2006. The review covers anion receptors that employ amides and thioamides, pyrroles and indoles, ureas and thioureas, ammonium, guanidinium, imidazolium, and receptors containing hydroxyl groups. There is a discussion of anion templated assembly, followed by a short section outlining modelling studies of these systems. (226 references.)

737 citations

References
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Journal ArticleDOI
TL;DR: The fluorescent photoinduced electron transfer chemosensors 2 and 3 were designed for the recognition of anions possessing two binding sides such as dicarboxylates and pyrophosphate; the anion recognition in DMSO takes place through the two charge neutral thiourea receptor sites with concomitant PET quenching of the anthracene moiety.

420 citations

Journal ArticleDOI
TL;DR: Two Colorimetric azobenzene based chemosensors 1 and 2 were designed for detection of transition-metal ions such as Cu(II) under physiological pH conditions and give rise to red-to-yellow color changes that are visible to the naked-eye and reversible upon addition of EDTA.

299 citations

Journal ArticleDOI
TL;DR: A novel colorimetric and fluorescent chemosensor ADDTU-1 bearing dual receptor sites, which shows specific optical signaling for AcO, H2PO4-, and F- over other anions and dual response toward AcO- andF- via PET and ICT mechanisms, is described.

247 citations