Spectrophotometric determination of acidity constants of 2-(2-Thiazolylazo)-Cresol in various water-organic solvent media mixtures using chemometrics methods

Determination of acid dissociation constants of Alizarin Red S, Methyl Orange, Bromothymol Blue and Bromophenol Blue using a digital camera

Acid dissociation constants (pK_a) are important parameters for the characterization of organic and inorganic compounds. They play a crucial role in different physical, chemical, and biological studies. Herein, we introduce a new approach for the determination of acid dissociation constant based on digital image analysis using a low-cost, precise, accurate, sensitive, and portable home-made, camera-based platform. Digital images of Alizarin Red S, Bromophenol Blue, Bromothymol Blue, and Methyl Orange solutions were captured at various pH values. The captured images were analysed to obtain the RGB (Red, Green, and Blue) colour intensities that are used to calculate the RGB colour absorbances. The pK_a values were calculated from the RGB colour absorbance–pH relationship using graphical and mathematical methods, and with the aid of DATAN software. For the four studied dyes, the results obtained from digital image analysis were in excellent agreement with the data of sophisticated spectrophotometers and the previously reported literature data.

Acid dissociation constants (pK_a) are important parameters for the characterization of organic and inorganic compounds.

Cobalt metal-mixed organic complex-based hybrid micromaterials: ratiometric detection of cyanide

A micrometer-sized hybrid crystalline material was facilely fabricated from the synergistic coordination chemistry of two types of 2-hydroxyazobenzene building blocks and cobalt ions. This hybrid crystalline material functioned as both receptor and signal reporter in cyanide (CN⁻) sensing with ratiometric absorption responses at 456 nm and 537 nm. The mechanism of CN⁻ sensing involves partial ligand dissociation accompanied by the formation of a new organic metal–CN⁻ adduct. We believe that this protocol would be valuable in achieving the expected selectivities and sensitivities for a wide variety of analytes in many chemical and biological systems in the future.

A cobalt metal-mixed organic complex-based hybrid micromaterial has been presented to detect CN⁻ with ratiometric absorption responses (A_{456 nm}/A_{537 nm}).