Instant Detection of Hydrogen Cyanide Gas and Cyanide Salts in Solid Matrices and Water by using Cu^II and Ni^II Complexes of Intramolecularly Hydrogen Bonded Zwitterions

Abstract

A series of intramolecularly hydrogen-bonded zwitterionic compartmental ligands HL1-HL4, containing a pendent diamine arm that is monoprotonated and an aldehyde functionality at two different ortho-positions of a 4-halophenoxide, is reported herein. Single-crystal X-ray diffraction (SXRD) provides persuasive evidence for the identification of this class of proton-transferred zwitterions at room temperature. The solid-state photoluminescent nature of these zwitterions remains intact in aqueous and organic solutions. Grinding of HL1 and HL2 with Cu /Ni salts develop turn-on probes 1-4. Compounds 1 and 4 are dinuclear Cu and Ni species, respectively. Compound 2 is a tetranuclear Cu complex. Interestingly, compound 3 is a mononuclear Ni species in which both nitrogen atoms in the pendant diamine arm are protonated and, therefore, not coordinated to the Ni center. All these probes (1-4) display an instant response to the poison gas hydrogen cyanide (HCN) and cyanide salts present in both solid matrices and aqueous (100 % water) solution. Selective and rapid sensing of HCN gas and cyanide salts in solid/soil/water phases, without any interference, by the mechanosynthesized complexes 1-4 can be perceived easily by the naked eye under a hand-held UV lamp.

Fabrication of a Cu(II)-Selective Electrode in the Polyvinyl Chloride Matrix Utilizing Mechanochemically Synthesized Rhodamine 6g as an Ionophore

“…In our recent endeavor, − we have showed how a green preparative technique called mechanochemical (MC) reactions can be useful and economical for the one-pot synthesis of artificial receptors. Performing a liquid-assisted grinding of a mechanosynthesized tridentate zwitterion with a very popular transducer moiety known as rhodamine 6g hydrazide (also prepared mechanochemically) has resulted in the synthesis of a pentadentate ionophore “L”. We have characterized this mechanochemically synthesized probe “L” by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR)–attenuated total reflection, and scanning electron microscopy (SEM) techniques.…”

A Highly Selective Turn-On Biosensor for Measuring Spermine/Spermidine in Human Urine and Blood

“…Therefore, CB@AG can measure spermine concentrations in a wide range. In order to estimate the limit of detection (LOD), we plotted [( F – F 0 )/( F α – F 0 )] against Log­[spermine] as described in our recent article . Here F 0 , F , and F α are the fluorescence intensities of the hydrogels without spermine, with spermine at a certain concentration, and in the presence of highest concentration of spermine used in the titration experiments, respectively.…”

“…The binding affinity of spermine for CB was determined by performing fluorimetric titration in which increasing addition of tetracationic spermine to the solution of CB in aqueous HEPES buffer solution resulted in the gradual enhancement of the emission peak intensity. We fitted the titration data points using the following nonlinear eq in which F 0 and F denote fluorescence intensities of CB at 440 nm without and with spermine/spermidine, respectively. In eq , F max is the fluorescence intensity of CB at 440 nm in the presence of an excess amount of spermine/spermidine.…”

“…For all lifetime measurements, a single exponential iterative fitting program analyzed the fluorescence decay curves. Lifetime studies were performed by following the procedure described in our earlier report . Rheological studies were carried out by a Physica MCR 301 rheometer (Anton Paar) using a pp50 (diameter 49.973 mm) probe.…”

“…Lifetime studies were performed by following the procedure described in our earlier report. 51 Rheological studies were carried out by a Physica MCR 301 rheometer (Anton Paar) using a pp50 (diameter 49.973 mm) probe. For freeze-drying, a Vir Tiz benchtop freeze-dryer was used.…”