The first O,C,S-coordinating pincer-type ligand and its application to the synthesis of a triorganotin cation stabilized by two different donor atoms

Article abstract of DOI:10.1021/om0600590

The syntheses and molecular structures of the bromo-substituted triarylphosphane sulfide (3-Br-5-t-Bu-C₆H₃)P(S)Ph ₂ (1), the arylphosphonic acid di-isopropyl ester {3-t-Bu-5-[P(S)Ph₂]-C₆H₃}P(O)(O-i-Pr) ₂ (2), its triphenyltin derivative {5-t-Bu-3-[P(S)Ph ₂]-2-(SnPh₃)-C₆H₂}P(O)(O-i-Pr) ₂ (3), and the corresponding triorganostannylium salt {4-t-Bu-2-[P(O)(O-i-Pr)₂]-6-[P(S)Ph₂]-C₆H ₂}SnPh₂⁺PF₆^- (4) are reported. By reaction with bromide ion, the latter is converted in situ to the intramolecularly coordinated benzoxaphosphastannole derivative [1(P),3(Sn)-SnPh₂OP(O)(O-i-Pr)-6-t-Bu-4-P(S)Ph₂]C ₆H₂ (5). Ab initio MO calculations on the ethoxy-substituted analogue of compound 4 indicate a reduced positive charge at the tin atom in comparison with previously reported {4-t-Bu-2,6-[P(O)(OEt) ₂]₂C₆H₂}SnPh₂ ⁺PF₆^-.