Reusable colorimetric and fluorescent chemosensors based on 1,8-naphthalimide derivatives for fluoride ion detection

Two 1, 8-naphthalimide derivatives, 2-(2-ethylhexyl)-6-(2-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzylidene)hydrazinyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (named as NAOZ) and 2-(2-ethylhexyl)-6-(2-(4-(5-phenyl-1,3,4-thiadiazol-2-yl)benzylidene)hydrazinyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (named as NATZ), containing hydrazone and thiadiazole/oxadiazole, were successfully synthesized. Compounds NAOZ and NATZ were further served as efficient reversible colorimetric and fluorescent chemosensors for fluoride ion over a wide range of other anions (Cl^-, Br^-, I^-, NO₃^-, ClO₄^-, HSO₄^-, BF₄^-, and PF₆^- as their (C₄H₉)₄N⁺ salts) because fluoride ion can deprotonate the hydrazone moiety, leading to the observed long-wavelength color change. Interestingly, CO₂ can recover the charge transfer (CT) absorption and photoluminescence intensities of compound NAOZ/NATZ + F^-, because CO₂ can react with a small amount of water to form acids, which can provide protons.

CO2 fixation and transformation on a thiolate-bridged dicobalt scaffold under oxidising conditions

CO2 fixation and conversion promoted by a thiolate-bridged dicobalt complex in the presence of an oxidant.

Migratory insertion and hydrogenation of a bridging azide in a thiolate-bridged dicobalt reaction platform

A novel well-defined thiolate-bridged dicobalt azido complex is converted to a rare sulfilimide-bridged dicobalt complex via nitrogen atom migratory insertion into the Co-S bond upon thermolysis. Intriguingly, the homolytic cleavage of hydrogen is achieved by this azide under mild conditions to furnish a partially hydrogenated azido complex.

Synthesis, structural characterization and conversion of dinuclear iron-sulfur clusters containing the disulfide ligand: [Cp*Fe(μ-η2:η2-bdt)(cis-μ-η1:η1-S2)FeCp*], [Cp*Fe(μ-S(C6H4S2))(cis-μ-η1:η1-S2)FeCp*], and [{Cp*Fe(bdt)}2(trans-μ-η1:η1-S2)]

The treatment of [Cp*Fe(μ-η²:η⁴-bdt)FeCp*] (1, Cp* = η⁵-C₅Me₅, bdt = benzene-1,2-dithiolate) with 1/4 equiv. of elemental sulfur (S₈) gave a dinuclear iron-sulfur cluster [Cp*Fe(μ-η²:η²-bdt)(cis-μ-η¹:η¹-S₂)FeCp*] (2), which contains a cis-1,2-disulfide ligand. When complex 2 further interacted with 1/8 equiv. of S₈, another sulfur atom inserted into an Fe-S bond to give a rare product [Cp*Fe(μ-S(C₆H₄S₂))(cis-μ-η¹:η¹-S₂)FeCp*] (3). Unexpectedly, a trans-1,2 disulfide-bridged diiron complex [{Cp*Fe(bdt)}₂(trans-μ-η¹:η¹-S₂)] (4) was isolated from the reaction of complex 1 with 1/2 equiv. of S₈, which represents a structural isomer of [2Fe-2S] ferredoxin-type clusters. In addition, cis-1,2-disulfide-bridged complex 3 can slowly convert into trans-1,2-disulfide-bridged complex 4 and the complex [Cp*Fe(μ-η²:η²-S₂)(cis-μ-η¹:η¹-S₂)FeCp*] (5) by self-assembly reaction at ambient temperature, which is evidenced by time-dependent ¹H NMR spectroscopy.

Graphene Oxide-Based Sensor for Ultrasensitive Visual Detection of Fluoride

Visual fluoride ion detection with a detection limit down to pmol L-1 is achieved through quenching/reactivating the fluorescence of N-doped graphene oxide.

Curcumin based chemosensor for selective detection of fluoride and cyanide anions in aqueous media

The conjugate N,N-dimethyl curcumin analogue fluorophore dye 1 has been synthesized and its performance as a sensor was demonstrated.