Selectivity of membrane electrodes based on derivatives of dibenzyltin dichloride

Abstract

Selectivity properties are established for membrane electrodes prepared by incorporating bis(p-methylbenzyl)tin dichloride, dibenzyltin dichloride, and bis(p-chlorobenzyl)tin dichloride in plasticized polymer membranes. These electrodes display an unusually high level of selectivity for dibasic phosphate over many common anions. Electrodes prepared with the p-chloro derivative possess the best detection limit and the highest degree of selectivity for phosphate. Selectivity coefficients are calculated for phosphate relative to the following groups of anions: salicylate, benzoate, thiocyanate, iodide, nitrate, bromide, chloride, acetate, fluoride, pyrophosphate, arsenate, adenosine 5'-cyclic monophosphate, adenosine 5'-monophosphate, adenosine 5'-diphosphate, and adenosine 5'-triphosphate. Tin-carbon hyperconjugation within the organotin compound is hypothesized to be critically important in the selective response to phosphate. Enhancement of tin-carbon hyperconjugation by increasing the electron-withdrawing power of substituents on the benzyl ring is predicted to provide even higher levels of selectivity for phosphate.

Anion recognition: fabrication of a highly selective and sensitive HPO4(2-) PVC sensor based on a oxo-molybdenum methyl-salen

“…Beyond this range, a gradual change in the potential was detected. The observed potential drift at the higher and lower pH values could be due to the decreasing of the concentration of MHP (formation of H 2 PO 4-and PO 4 3-at lower and higher pH, respectively).…”

“…1 Recent studies show that leaching of PO 4 2-as small as 10 μg L -1 from agricultural land can contribute to eutrophication. 2 Thus, due to the increasing use of phosphate fertilizers in agricultural industries, monitoring of phosphate ions is very important.…”

“…Recently, a number of hydrogen phosphate membrane sensors based on different ion carriers such as dialkyl and diaryltin derivatives, uranyl salophen, vanadyl salen, vanadyl salophen, bis-thiourea and modified calix arene have been reported. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] In recent years, we have introduced a number of selective membrane sensor for different anions such as Cl -, Br -, I -, SO 4 2-, NO 2 -, SCN -, HPO 4 2-, and I 3 -. 12,[16][17][18][19][20][21][22][23][24][25][26] In this report we introduce the synthesis of a oxomolybdenum methyl-salen and its application in fabrication of a highly selective and sensitive MHP membrane sensors for fast monitoring of MHP in various granular fertilizers as well as waste water of fertilizer industry.…”

New Highly Selective Picrate Sensors Based on Charge-Transfer Complexes

“…33 When the selectivity of the sensor differs from the Hofmeister selectivity sequence, it is generally not governed by simple anion lipophilicity, but by specific chemical interactions between the neutral carriers and anions. 42,43 Herein, the unique interaction between the neutral carrier (DD18C6) or the Kryptofix 222 donor, and the picrate anion acceptor, which has three electronwithdrawing nitro groups, increase the electron affinity of it. This makes the sensors highly selective for picrate anion acceptor over other anions where there is no analyte anion recognition for them (the anions in this case are not acceptors).…”

Anion Selectivities of Dibutyltin Dihalides as Neutral Carriers for Ion-Selective Electrodes

“…4,18 Therefore, it seems that the electronegative substituent Y on the Sn atom significantly influences the anion selectivity if a sufficiently fast exchange of the electronegative substituent Y does not occur or if another electronegative substituent Y remains on the Sn atom evenafter an exchange of one electronegative substituent Y occurs. Dialkyltin dihalide compounds form complexes more readily than trialkyltin halide compounds because the Lewis acidity of the tin center in dialkyltin dihalides R2SnY2 is increased by two highly electronegative substituents Y.…”