Azo Schiff bases as colorimetric and fluorescent sensors for recognition of F−, Cd2+ and Hg2+ ions

2014 ◽  
Vol 6 (18) ◽  
pp. 7384-7393 ◽  
Author(s):  
Raziyeh Arabahmadi ◽  
Masoumeh Orojloo ◽  
Saeid Amani
Keyword(s):  
Fluorescence Spectroscopy ◽  
Charge Density ◽  
Schiff Bases ◽  
Electrochemical Techniques ◽  
Fluorescent Sensors ◽  
Spectral Change ◽  
Colorimetric Sensing ◽  
Anion Sensing ◽  
Receptor Molecule ◽  
Naked Eye

The optical and colorimetric sensing properties of H2L1–H2L3 for anions were investigated by the naked eye and UV-Vis and fluorescence spectroscopy. The spectral change of H2L1–H2L3 is due to the anion induced deprotonation and hence an increase in charge density and rigidity of the receptor molecule. The anion sensing abilities of the receptors toward halide anions were also monitored by electrochemical techniques.

scholarly journals Cation Sensing Capabilities of A Nitrophenyl Cinnamaldehyde Derivative

Molekul ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 191
Author(s):  
Venty Suryanti ◽  
Fajar Rakhman Wibowo ◽  
Ahmad Marzuki ◽  
Meiyanti Ratna Kumala Sari
Keyword(s):  
Charge Transfer ◽  
Organic Compound ◽  
Charge Density ◽  
Absorption Spectra ◽  
Color Change ◽  
Metal Cations ◽  
Colorimetric Sensing ◽  
Color Changes ◽  
Ligand Charge Transfer ◽  
Cation Sensing

The cationic chemosensor based on organic compound bearing an aminophenol moiety as a receptor for metal analyte and a cinnamaldehyde moiety as chromophoric fragment has been developed. In this work, we report the colorimetric sensing of nitrophenyl cinnamaldehyde derivative, namely methyl-3-(2-hidroxy-5-nitrophenyl amino)-3-phenylpropanoate, towards a variety of metal cations, such as Cu2+, Fe3+, Ni2+ and Zn2+. The cation sensing abilities of the sensor were observed for Cu2+and Fe3+ with a color change from colorless to pink and faint yellow, respectively, The characteristic UV-Vis spectra changes were observed upon addition of Cu2+and Fe3+ cations. The hypsochromic absorption spectra shifts were obtained, indicating the cations and sensor complexations had formed. A metal-to-ligand-charge-transfer (MLCT) had occurred and the charge density of the sensor changed resulting in appearance of new absorption peaks in the UV-Vis spectra and color changes of the sensor solution upon addition of the Cu2+and Fe3+.  

Naked Eye Chemosensing of Anions by Schiff Bases

2020 ◽  
pp. 1-18 ◽  
Author(s):  
Hafiz Muhammad Junaid ◽  
Madeeha Batool ◽  
Farah Wahida Harun ◽  
Muhammad Saleem Akhter ◽  
Nabila Shabbir
Keyword(s):  
Schiff Bases ◽  
Naked Eye

scholarly journals Hyperchromatic structural color for perceptually enhanced sensing by the naked eye

2020 ◽  
Vol 117 (48) ◽  
pp. 30107-30117
Author(s):  
Tahmid H. Talukdar ◽  
Bria McCoy ◽  
Sarah K. Timmins ◽  
Taufiquar Khan ◽  
Judson D. Ryckman
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Form Factors ◽  
Optical Filters ◽  
Color Filter ◽  
Structural Color ◽  
Label Free ◽  
Colorimetric Sensing ◽  
Large Area ◽  
Naked Eye

Colorimetric sensors offer the prospect for on-demand sensing diagnostics in simple and low-cost form factors, enabling rapid spatiotemporal inspection by digital cameras or the naked eye. However, realizing strong dynamic color variations in response to small changes in sample properties has remained a considerable challenge, which is often pursued through the use of highly responsive materials under broadband illumination. In this work, we demonstrate a general colorimetric sensing technique that overcomes the performance limitations of existing chromatic and luminance-based sensing techniques. Our approach combines structural color optical filters as sensing elements alongside a multichromatic laser illuminant. We experimentally demonstrate our approach in the context of label-free biosensing and achieve ultrasensitive and perceptually enhanced chromatic color changes in response to refractive index changes and small molecule surface attachment. Using structurally enabled chromaticity variations, the human eye is able to resolve ∼0.1-nm spectral shifts with low-quality factor (e.g., Q ∼ 15) structural filters. This enables spatially resolved biosensing in large area (approximately centimeters squared) lithography-free sensing films with a naked eye limit of detection of ∼3 pg/mm2, lower than industry standard sensors based on surface plasmon resonance that require spectral or angular interrogation. This work highlights the key roles played by both the choice of illuminant and design of structural color filter, and it offers a promising pathway for colorimetric devices to meet the strong demand for high-performance, rapid, and portable (or point-of-care) diagnostic sensors in applications spanning from biomedicine to environmental/structural monitoring.

Novel nitro-substituted formazan derivatives: selective ratiometric and colorimetric chemosensors for fluoride anion sensing detectable by the naked eye

2020 ◽  
Vol 44 (22) ◽  
pp. 9485-9492 ◽  
Author(s):  
Gulsen Turkoglu
Keyword(s):  
Anion Recognition ◽  
Fluoride Anion ◽  
Anion Sensing ◽  
First Report ◽  
Naked Eye

This study is the first report of formazan derivatives designed as chemosensors for fluoride anion recognition.

Size and shape regulated synthesis of silver nanocapsules for highly selective and sensitive ultralow bivalent copper ion sensor application

2017 ◽  
Vol 41 (10) ◽  
pp. 4006-4013 ◽  
Author(s):  
Balakumar Vellaichamy ◽  
Prakash Periakaruppan
Keyword(s):  
Copper Ions ◽  
Copper Ion ◽  
Colorimetric Sensing ◽  
Ion Sensor ◽  
Sensor Application ◽  
Size And Shape ◽  
Naked Eye ◽  
Bivalent Copper ◽  
Shape Controlled

The development of highly robust, quantitative, sensitive and naked eye colorimetric sensing of bivalent copper ions using bio-inspired synthesis of size and shape controlled silver nanocapsules (AgNCs) is reported herein.

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