Straightforward Donor Atom Switching: From P,C,P- to Various Y,C,Y-Pincer (Y = O, S, Se) Organotin(IV) Compounds and Cations

The oxidation of phosphorus atoms in P,C,P-pincer organotin(IV) compounds ArSnCl₃ (1), ArSnPhCl₂ (2) and ArSnPh₂Cl (3) (Ar = 2,6-(tBu₂PO)₂C₆H₃) with Me₃NO (or H₂O₂), S or Se furnished compounds ArYSnCl₃ (1Y), ArYSnPhCl₂ (2Y), and ArYSnPh₂Cl (3Y) (ArY = 2,6-(tBu₂(Y)PO)₂C₆H₃; Y = O, S or Se, except 3O). Their reactions with Na[BArF] ([BArF] = [3,5-(CF₃)₂C₆H₃]₄B) afforded salts containing organotin cations [ArYSnCl₂][BArF] (1Y+[BArF]-), [ArYSnPhCl][BArF] (2Y+[BArF]-), and [ArYSnPh₂][BArF] (3Y+[BArF]-). The oxidation of compound 3 with 1 equiv of Me₃NO gave compound [ArPOSnPh₂Cl] (3PO) (ArPO = 2-(tBu₂PO)-6-(tBu₂(O)PO)C₆H₃) and its subsequent oxidation by S or Se allowed the isolation of mixed donor compounds [ArOYSnPh₂Cl] (3OY) (ArOY = 2-(tBu₂(O)PO)-6-(tBu₂(Y)PO)C₆H₃; Y = S or Se). Compounds 3PO and 3OY were converted to salts [ArPOSnPh₂][BArF] (3PO+[BArF]-) and [ArOYSnPh₂][BArF] (3OY+[BArF]-; Y = S or Se). All compounds were characterized by multinuclear NMR spectroscopy in solution, and their molecular structures (except 3OS) were determined by single crystal (sc) X-ray diffraction analysis. The intramolecular P/Y → Sn interactions and their influence on the structures of complexes were analyzed in detail using NMR data and solid-state structures. The experiments were corroborated by a DFT study including NBO and AIM-analysis, which reveals the role of chalcogen centers in tuning the thermodynamic stabilization in the pincer complexes.