Simplicity Meets Beauty. Trapping Molecular Dimethyltin Oxide in the Novel Organotinoxo Cluster [MeN(CH2CH2O)2SnMe2·Me2SnO]3

The syntheses are reported of the 1,1,5-trimethyl-2,8-dioxa-5-aza-1-stannabicyclo[3.3.0]­octane MeN­(CH2CH2O)2SnMe2 (1), its monosodium aminoalcoholate adduct [MeN­(CH2CH2O)2SnMe2·MeN­(CH2CH2ONa)­(CH2CH2OH)]2 (2), and the hexanuclear organotin oxo cluster [MeN­(CH2CH2O)2SnMe2·Me2SnO]3 (3). The compounds were characterized by 1H, 13C, and 119Sn NMR spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction analysis. In the solid state, compound 1 is a tetramer that is brought about by intermolecular O→Sn interactions. In solution, however, it shows a monomer ⇌ dimer equilibrium that is fast on the 1H, 13C, and 119Sn NMR time scales at room temperature. All compounds show intramolecular N→Sn interactions at Sn–N distances ranging between 2.378(3) Å (2) and 3.026(3) Å (3·0.25H2O). Compound 3 can formally be regarded as a molecular dimethyltin oxide being trapped by head-to-tail complexation with a stannabicyclooctane. In solution, it slowly falls apart into 1 and Me2SnO.