Anion Selectivities of Triorganyltin Acetates and Halides in Solvent Polymeric Membranes

Abstract

A series of triorganyltin compounds of the type R,SnY and R:R2SnY has been studied in view of their anion selectivities exhibited in solvent polymeric membranes. A large variety of selectivity patterns has been observed first by varying the concentration of a given ionophore in the membrane phase, and second by using ionophores which differ in the organic substituents R on the Sn centre. With more space consuming substituents R, the observed selectivity patterns become more and more similar to that of a blank membrane, suggesting steric hindrance for the pentacoordination of the corresponding ionophores by sample anions.Introduction. -Certain organotin compounds induce anion selectivity in membranes [l-61 and act as electrically neutral carriers for anions [4] [6] (see also [7]). They are attractive candidates for anion sensors with a selectivity sequence deviating from the one observed with classical anion-exchanger membranes [5] [6] (Hofmeister lyotropic anion selectivity sequence:

Tributyl- and Triphenyltin Benzoates, Phenylacetates, and Cinnamates as Anion Carriers: an Electrochemical Assessment Coupled to Structural NMR Studies and AM1 Calculations

“…While low chloride response of triphenyltin chloride has been previously attributed [16] to the steric bulkiness of the Ph groups, the results obtained from the compounds presented here indicate that the observed behavior is rather strongly dependent on the Lewis-acidity characteristics of the carrier. The Sn-atom in the Bu 3 Sn moiety is a weaker Lewis acid than it is in the Ph 3 Sn [26] [28].…”

“…Organotin compounds of the type R 3 SnX have been found to selectively bind and transport anions in biological [14] as well as in plasticized polymeric membranes [7] [15]. In particular, triorganotin acetates and halides (i.e., (acetyloxy)-and halogenotrialkylstannanes) have shown increased potentiometric response towards chloride [16], depending on the concentration of the carrier in the membrane and on the bulkiness of the organic substituents at the Sn-atom. By contrast, the selectivity is not strongly influenced by the nature of the electronegative substituent X.…”

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

“…This tendency has been also indicated by R3SnCl (R=Bu, Oc). 14,17 Next, a series of di-n-butyltin compounds with different electronegative substituents Y (Y=F, I, OMe) were investigated as ionophores. The concentration of ionophores was chosen as 10.0wt%.…”

“…[14][15][16][17][18] A variety of anion selectivities of trialkyltin compounds has been found by using ionophores which differ in the organic substituents R on the Sn atom. [16][17][18] With more space-consuming substituents R, the observed selectivity patterns have been more similar to that of a blank membrane. Therefore, one may conclude that the steric hindrance interferes with the formation of the pentacoordination of the ionophores with sample anions X -.…”

Anion Selectivity of Tetravalent Tin Compounds in Membranes Studied by 119Sn‐, 13C‐ and 1H‐NMR

“…6 e ) demonstrates that partially pentacoordinated tin species remain present in this membrane. [28] and Bu,SnOAc according to [8]. Bu,SnCN and OC,Sn were provided from Aldrich GmbH, D-Steinheim (purum); they were recrystallized or distilled in a 'Kugelrohr' apparatus, until only 1 signal was observed in the "'Sn-NMR spectrum.…”