Intramolecularly Coordinated Bis(crown ether)-Substituted Organotin Halides as Ditopic Salt Receptors

The synthesis of the bis­(crown ether)-substituted organostannanes X<sub>2</sub>Sn­(CH<sub>2</sub>-[16]-crown-5)<sub>2</sub> (<b>3</b>, X = I; <b>4</b>, X = Br; <b>5</b>, X = Cl; <b>6</b>, X = F) and X<sub>2</sub>Sn­(CH<sub>2</sub>-[13]-crown-4)<sub>2</sub> (<b>10</b>, X = I; <b>11</b>, X = Br; <b>12</b>, X = F) is reported. The compounds have been characterized by <sup>1</sup>H, <sup>13</sup>C, <sup>19</sup>F, and <sup>119</sup>Sn NMR spectroscopy, elemental analyses, and electrospray ionization mass spectrometry (ESI-MS). Single-crystal X-ray diffraction analyses reveal a distorted-octahedral <i>cis</i>,<i>cis</i>,<i>trans </i>configuration of the tin atoms in compounds <b>4</b>–<b>6</b> and <b>10</b>–<b>12</b> as a result of intramolecular O→Sn coordination. The ability of the host molecules to form mono- and ditopic complexes with various halide salts in different solvents, including water, has been investigated by NMR spectroscopy and ESI-MS.