Ph(3-n)XnSnCH2-16-crown-5 (X = F, Cl, Br, I, SCN; n = 1, 2): Intramolecular O → Sn Coordination versus Ditopic Complexation of Sodium Thiocyanate†

The synthesis of the organotin-substituted crown ethers Ph(3-n)XnSn-CH2-16-crown-5 (1, n = 0; 2, n = 1, X = I; 3, n = 1, X = Br; 4, n = 1, X = Cl; 5, n = 1, X = F; 6, n = 1, X = SCN; 7, n = 2, X = Cl; 8, n = 2, X = I) is reported. The compounds are characterized by elemental analyses and 1H, 13C, 19F, 23Na, and 119Sn NMR spectroscopy and in the case of compound 4 also by 119Sn MAS NMR spectroscopy. Single-crystal X-ray diffraction analyses reveal for compounds 2−5 trigonal-bipyramidally configurated tin atoms with intramolecular Sn−O distances ranging between 2.530(2) (5) and 2.571(1) Å (4), whereas the tin atom in compound 1 shows a distorted tetrahedral configuration. The tin atoms in compounds 7 and 8 are hexacoordinated with intramolecular Sn−O distances ranging between 2.473(1) (7) and 2.522(1) Å (7). NMR spectroscopy reveals the ability of compound 4 to form, in competition with intramolecular O → Sn coordination, a ditopic complex with NaSCN.