Bis[di-n-alkyl(fluoro)stannyl]methanes, (R2FSn)2CH2 (R = n-octyl, n-dodecyl):: Stable fluoride-selective carriers

The synthesis of bis[di-n-alkyl(fluoro)stannyl]methanes, [(R-2)FSn](2)CH2, (3, R n-octyl; 4, R = n-dodecyl), is reported and their unprecedented dimeric structure in solution with pentacoordinate tin atoms is rationalized on the basis of F-19 and Sn-119 NMR spectroscopy, osmometric molecular mass determination and electrospray mass spectrometry (ESMS). F-19 and Sn-119 MAS NMR and Mossbauer spectroscopy also indicate pentacoordinate tin atoms for the solid state. The ability Of compounds 3 and 4 to bind fluoride ion selectively and reversibly is evaluated through potentiometric measurements. Compared with the previously reported organotin(IV)based fluoride ionophore [Cl(Ph-2)Sn](2)CH2, 3 and 4 exhibit a drastically improved lifetime, while retaining their high preference for fluoride over all other lipophilic anions evaluated. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).