Hydrolysis of Dinuclear Spacer-Bridged Diorganotin(IV) Triflates. A Novel Cationic Double Ladder with Supramolecular Association

Abstract

A series of oligomethylene-bridged diorganotin triflates R(OTf) 2 Sn(CH 2 ) n Sn(OTf) 2 R (R = CH 2 SiMe 3 ; n = 3, 4, 8, 10) were synthesized by reaction of triflic acid with the precursor oxides R(O)Sn(CH 2 ) n Sn(O)R. On the basis of 1 1 9 Sn NMR (in acetonitrile) the triflates appear to be the simple six-coordinated ionic species [(MeCN) 4 (RSn(CH 2 ) n SnR)(MeCN) 4 ] 2 + . These triflates readily undergo hydrolysis to give products, the identity of which depends on the length of the oligomethylene bridge. For n = 3 (5), the solid-state structure shows association of two dimeric units, which results in a tetracationic double ladder. Extensive hydrogen bonding gives rise to a supramolecular association. Solution 1 1 9 Sn NMR and ES MS suggest some dissociation of 5 into dimers containing four tin atoms and possibly monomers containing two tin atoms. A rudimentary solid-state structure for n = 4 (6) indicates a linear polymer based on dimeric (four tin atoms) units. The structure of 6 also features extensive hydrogen bonding, this time effectively giving rise to alternating layers of cations and anions.