Gregor Reeske

Selective fluoride recognition and potentiometric properties of ion-selective electrodes based on bis(halodiphenylstannyl)alkanes

Abstract A series of bis(halodiphenylstannyl)alkanes (Ph 2 XSn) 2 (CH 2 ) n , (X: Cl, Br, OAc, n =1–4) have been evaluated as fluoride ionophores in polymeric-membrane ion-selective electrodes. It is shown that the selectivity pattern of these molecules is governed by their structural characteristics. An entirely non-Hofmeister selectivity sequence with a remarkable preference towards fluoride is obtained for bis(chlorodiphenylstannyl)methane, (Ph 2 ClSn) 2 CH 2 . The latter compound was utilised for further studies on the improvement of the ISEs selectivity towards fluoride. The optimum membrane composition for best potentiometric performance was achieved with DOS-elasticised membranes doped with 10xa0mol% KTpClPB, suggesting that this compound operates via a charged-carrier mechanism. This membrane composition results in a preference to fluoride over several lipophilic anions, such as perchlorate, nitrate and iodide.

Charge separation by ditopic complexation in the solid state: molecular structure of {Ph2(I)SnCH2Sn(Ph)(I)CH2-[16]-crown-5}.NaF.CH3OH.

An intramolecular O-H-F hydrogen bridge involving a methanol molecule provides communication between the strongly separated sodium cation and fluoride anion in sodium fluoride that is, for the first time and despite its high lattice energy, ditopically complexed by an organotin-substituted crown ether.

THE MOLECULAR STRUCTURE OF 1,2-BIS(TRIPHENYLSTANNYL)ETHANE [(C6H5)3SnCH2]2

Figure 1. Molecular structure (30 % probability ellipsoids) of [(CeHs^SnCl·^· Symmetry transformations used to generate equivalent atoms: a = -x, -y, -z-. Selected bond distances and angles: Sn(l)-C(l) 2.154(2), Sn(l)-C(l 1)2.138(3), Sn(l)-C(21) 2.135(3), Sn(l)-C(31) 2.142(2), Sn(2)-C(2) 2.147(2), Sn(2)-C(41) 2.130(3), Sn(2)-C(51)2.131(2), Sn(2)-C(61) 2.137(3), Sn(3)-C(3) 2.167(2), Sn(3)-C(71) 2.151(3), Sn(3)0(81)2.141(3), Sn(3)-C(91) 2.147(3), C(l)-C(2) 1.515(3), C(3>C(3a) 1.521(5), C(l)-Sn(l)-C(ll) 107.17(10), C(l)-Sn(l)-C(21) 111.75(10), C(l)-Sn(l)-C(31) 110.18(9), C(2)-Sn(2)-C(41) 110.97(10), C(2)Sn(2)-C(51) 108.94(9), C(2)-Sn(2)-C(61) 107.58(10), C(3)-Sn(3)-C(71) 113.02(9), C(3)-Sn(3)-C(81) 108.29(10), C(3)-Sn(3)-C(91) 111.15(10), C(11)-Sn(l)-C(21) 108.07(10), C(11)-Sn(l)-C(31) 109.09(10), C(21)-Sn(l)-C(31) 110.47(10), C(41)-Sn(2)-C(51) 109.94(10), C(41)-Sn(2)-C(61) 109.13(10), C(51)-Sn(2)C(61) 110.27(10), C(71)-Sn(3)-C(81) 105.51(10), C(71)-Sn(3)-C(91) 108.61(10), C(81)-Sn(3)-C(91) 110.10(9), C(l)-C(2)-Sn(2) 113.73(16), C(2)-C(l)-Sn(l) 113.80(16), C(3A)-C(3)-Sn(3) 114.1(2).

4-(Di­phenyl­phosphinoyl)-3-methyl-N-phenyl-1,2-isoxazole-5-carbox­amide

The title compound, C23H19N2O3P, was prepared by the reaction of ethynyldixadphenylxadphosphine oxide with phenyl isocyanate, triethylxadamine and nitoethane in benzene. The molecular structure is stabilized by an intramolecular N—H⋯O hydrogen bond.