Synthesis and Structural Studies on Dimeric Organotin Cations

Abstract

Novel dimeric organotin cations [R 2 SnOH(OTf)(H 2 O)] 2 (R = n -Bu, t -Bu, and 2-phenylbutyl; Tf = CF 3 SO 2 ) were synthesized from R 2 SnO and TfOH. The structures of these compounds were investigated by single-crystal X-ray analysis and solid-state 119 Sn NMR in the solid state and 119 Sn NMR spectra together with electrical conductivity measurements in solution. tert -Butyltin and 2-phenylbutyltin derivatives have cationic structures both in the solid state and in solution. The n -butyltin derivative is nonionic in the solid state but dissociates into ionic species in solution. The H 2 O molecule in this compound can be readily replaced by hexamethylphosphoric triamide (HMPA); the resulting adduct has a similar structure. The corresponding nitrate has a nonionic dimeric structure with bidentate nitrate coordination, [t-Bu 2 SnOH(NO 3 )] 2 . As such, it is concluded that both bulky alkyl groups attached on tin and electronegative ligands such as triflate are crucial for generation of the cationic species.