Hydrazine functionalized probes for chromogenic and fluorescent ratiometric sensing of pH and F−: experimental and DFT studies

Abstract

Two novel hydrazine based sensors, BPPIH (N,N-bis(perfluorophenyl)isophthalohydrazide) and BPBIH (N,N-bis(perfluorobenzylidene)isophthalohydrazide), are presented here. BPPIH is found to be a highly sensitive pH sensor in the pH range 5.0 to 10.0 in a DMSO-water solvent mixture with a pK value of 9.22. Interesting optical responses have been observed for BPPIH in the above mentioned pH range. BPBIH on the other hand turns out to be a less effective pH sensor in the above mentioned pH range. The increase in fluorescence intensity at a lower pH for BPPIH was explained by using density functional theory. The ability of BPPIH to monitor the pH changes inside cancer cells is a useful application of the sensor as a functional material. In addition fluoride (F) selectivity studies of these two chemosensors have been performed and show that between them, BPBIH shows greater selectivity towards F. The interaction energy calculated from the DFT-D3 supports the experimental findings. The pH sensor (BPPIH) can be further interfaced with suitable circuitry interfaced with desired programming for ease of access and enhancement of practical applications.

A Harmonized Applied and Theoretical Exploration for Nanomolar Level Recognition of Perilous F− and CN− by Multichannel Chemosensor: Proposition of Hg2+‐Mediated Logic Gate Imitator

“…With the aim of asserting the mode of host-guest interaction, DFT calculations were employed which were completely corroborated with the experimental upshots. [42,56] Our supposition about the better interaction of the chemosensor towards F À in compared to CN À as a consequence of more electronegativity and smaller size of F À was entirely affirmed from the DFT studies. From the theoretical outcomes, lowering of both energy and HOMO-LUMO gap along with the elongation of -NH bond in presence of the analytes asserted the interaction between PMA and the targeted analytes.…”

“…[3] Among various toxic anions, detection of fluoride (F À ) has gained substantial contemplation owing to its various effects in physiological systems. [4,42] F À is a conventional component of hypnotics, anesthetics, military nerve gases, psychiatric drugs, cockroach and rat poisons etc., while superfluity (> 1.5 ppm) of this anion causes dental fluorosis, depression, bone malady, collagen fracture, thyroid activity and even cancer. [5][6][7][8] Therefore, recognition of F À even at very low concentration is a noteworthy concern in recent times.…”

“…Therefore, the premeditated presence of the electron withdrawing -F group attached to the pentafluorophenyl part enhanced the acidity of the adjacent À NH and À CH protons, which in turn can exert strong H-bonding interactions towards F À and CN À with high sensitivity and selectivity. [42] However, F À , being the smallest and most negatively charged anion, creates the sturdiest H-bonding attraction with the polar protons resulting in better response towards PMA in compared to CN À . [1,17] The synthesized sensory probe was characterized by SCXRD, ESI-MS, FTIR and 1 H-NMR experiments.…”

A Metallogel Based on a Zwitterionic Spirocyclic Meisenheimer Complex: Sensing of Fluoride Ions in Water and Moisture Content in Organic Solvents

“…[21][22][23][24] In recent times, scientists from all over the world have designed different types of colorimetric and fluorescent chemosensors of fluoride ion. [25][26][27][28][29][30][44][45][46][47][52][53][54][55][56][57][58][59][60][61][62][63][64][65]69] But gel-based detection is very less. [31][32][33][34] In general, using fluorescence-based sensors, we can easily detect very less quantity of fluoride in the range of 1-100 ppb [25][26]30,[44][45] as well as in the higher range 100-1000 ppb.…”

“…Along with this, fluoride sensing is also important in different industrial processes, uranium enrichment process, medical treatment, aluminium refining, organic synthesis, nerve gas attack, etc . In recent times, scientists from all over the world have designed different types of colorimetric and fluorescent chemosensors of fluoride ion ,,,. But gel‐based detection is very less .…”