Hydrolysis of dinuclear spacer-bridged diorganotin(IV) triflates. A novel cationic double ladder with supramolecular association

摘要

A series of oligomethylene-bridged diorganotin triflates R(OTf)(2)Sn(CH2)(n)Sn(OTf)(2)R (R = CH2SiMe3; n = 3, 4, 8, 10) were synthesized by reaction of triflic acid with the precursor oxides R(O)Sn(CH2)nSn(O)R. On the basis of Sn-119 NMR (in acetonitrile) the triflates appear to be the simple six-coordinated ionic species [(MeCN)(4)(RSn(CH2)nSnR)(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 119Sn 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. [References: 37]