The First Structurally Authenticated Compound Containing a Bond between Divalent Tin and Tetravalent Tin

The reaction of 1 equiv of [Li(thf)₃·Sn(SiMe₃)₃] (1) with [Sn(2-{(Me₃Si)₂C}-C₅H₄N)Cl] in Et₂O at ambient temperature affords the corresponding divalent Sn−tetravalent Sn compound, [Sn(2-{(Me₃Si)₂C}-C₅H₄N){Sn(SiMe₃)₃}] (2) in high yield. A single-crystal X-ray diffraction study reveals 2 to be monomeric and the divalent Sn−tetravalent Sn bond to be 2.8689(5) Å; this is the first measurement of such a bond. The ¹¹⁹Sn{¹H} NMR spectrum exhibits two singlet resonances at δ 897 and −502, each with well-resolved, isotopically shifted, ¹¹⁹Sn and ¹¹⁷Sn satellites (ca. 6700 and ca. 6400 Hz, respectively); this is the first measurement of ¹J coupling between Sn atoms of different valence.