Organotin(IV) hypervalent pseudohalides. Synthesis and structural characterization

• Diorgano- and triorganotin(IV) pseudohalides with 2-(Me2NCH2)C6H4 groups.
• Hypervalent 10-Sn-5 and 12-Sn-6 species.
• The intramolecular N→Sn coordination induces planar chirality and chirality to tin.
• Monodentate vs. bridging behavior of the NCE− (E = S, Se) ligand.
• Polymeric associations through CH⋯Cg or Cg⋯Cg intermolecular contacts.

Tri- and diorganotin(IV) pseudohalides of type [2-(Me2NCH2)C6H4]R2Sn(NCE) [E = S, R = Me (1); E = Se, R = Me (2), Ph (3)] and respectively [2-(Me2NCH2)C6H4]RSn(NCE)2 [E = S, R = nBu (4), Ph (5), 2-(Me2NCH2)C6H4 (6); E = Se; R = 2-(Me2NCH2)C6H4 (7)] were obtained by reacting the appropriate organotin(IV) chlorides and alkali metal pseudohalides in stoichiometric amounts. The new species were characterized by multinuclear NMR (1H, 13C, 119Sn and 77Se where appropriate), IR spectroscopy and mass spectrometry. Both the 119Sn NMR and the X-ray diffraction studies evidenced the formation of Sn–NCE bonds in these compounds. For compounds 1–4, 6 and 7 the single-crystal X-ray diffraction studies revealed intramolecular Me2N→Sn interactions and the formation of hypervalent species 10-Sn-5 in compounds 1–3 and 12-Sn-6 in 4, 6 and 7, respectively. Compounds 1–3 are monomeric species, with monodentate isochalcogenocyanato ligands, while in 4 one of the NCE− ligands behave as a bridging moiety, thus resulting in dimeric associations. Short π CHγ-CH2⋯Cg and respectively Cg⋯Cg intermolecular contacts resulted in polymeric chains of dimmers in 4 and 3D supramolecular networks in 6 and 7, respectively. The reactions of [2-(Me2NCH2)C6H4]RSnCl2 and MECN in an 1:1 molar ratio resulted in the formation of a mixture of [2-(Me2NCH2)C6H4]RSnCl2, [2-(Me2NCH2)C6H4]RSn(NCE)2 and [2-(Me2NCH2)C6H4]RSnCl(NCE) [E = S, R = Ph (8), 2-(Me2NCH2)C6H4 (9); E = Se, R = 2-(Me2NCH2)C6H4 (10)].

Several tri- and diorganotin(IV) compounds of type [2-(Me2NCH2)C6H4]R2Sn(NCE) and [2-(Me2NCH2)C6H4]RSn(NCE)2 [R = Me, nBu, Ph, 2-(Me2NCH2)C6H4, E = S, Se] were prepared and structurally characterized, both in solution and in solid state. The intermediary formed [2-(Me2NCH2)C6H4]RSnCl(NCE) takes part to redistribution reactions in solution.Figure optionsDownload as PowerPoint slide