10.1021/om970739q.s001 Mara Staffilani Mara Staffilani Giuliana Bonvicini Giuliana Bonvicini Jonathan W. Steed Jonathan W. Steed K. Travis Holman K. Travis Holman Jerry L. Atwood Jerry L. Atwood Mark R. J. Elsegood Mark R. J. Elsegood Bowl vs Saddle Conformations in Cyclononatriene-Based Anion Binding Hosts American Chemical Society 1998 Ru BF CHMe bowl vs Saddle Conformations binding constants 2 n 1 H NMR titration studies anion affinity MeC bind anions 1 H NMR complexes 6 nitromethane solution host 2 displays CF anion complexation behavior saddle conformation ligand 4 9 results crystallography 1998-04-03 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Bowl_vs_Saddle_Conformations_in_Cyclononatriene-Based_Anion_Binding_Hosts/3780933 The synthesis of organometallic complexes [{Ru(<i>p</i>-MeC<sub>6</sub>H<sub>4</sub>CHMe<sub>2</sub>)}<i><sub>n</sub></i>(C<sub>21</sub>H<sub>24</sub>S<sub>3</sub>)][CF<sub>3</sub>SO<sub>3</sub>]<sub>2</sub><i><sub>n</sub></i> (<i>n</i> = 1, <b>6</b>; <i>n</i> = 2, <b>7</b>) and [{Ir(C<sub>5</sub>Me<sub>5</sub>)}<sub>2</sub>(C<sub>21</sub>H<sub>24</sub>S<sub>3</sub>)][CF<sub>3</sub>SO<sub>3</sub>]<sub>4</sub> (<b>9</b>) based upon the trimeric macrocycle cyclotris(dimethylthiophenylene) (<b>4</b>) is reported. A saddle conformation is identified for the free ligand <b>4</b> and complexes <b>6</b> and <b>9</b> by X-ray crystallography. The anion complexation behavior of complex <b>9</b> is compared with the related cyclotriveratrylene complex [{Ru(<i>p</i>-MeC<sub>6</sub>H<sub>4</sub>CHMe<sub>2</sub>)}<sub>2</sub>(C<sub>27</sub>H<sub>30</sub>O<sub>6</sub>)][CF<sub>3</sub>SO<sub>3</sub>]<sub>4</sub> (<b>2</b>), which possesses a bowl-shaped conformation, by <sup>1</sup>H NMR titration studies in a variety of solvents. While host <b>2</b> displays a significant affinity for halides with binding constants of up to 1.25(7) × 10<sup>3</sup> M<sup>-1</sup> in nitromethane solution, the absence of a molecular cavity in <b>9</b> results in very little specific anion affinity. The 1,3-alternate calix[4]arene complex [{Ru(η<sup>6</sup>-<i>p-</i>MeC<sub>6</sub>H<sub>4</sub>CHMe<sub>2</sub>)}<sub>2</sub>(η<sup>6</sup>:η<sup>6</sup>-C<sub>40</sub>H<sub>48</sub>)][BF<sub>4</sub>]<sub>4</sub> (<b>11</b>) is also reported and shown to bind anions in an unusual C−H···anion hydrogen-bonding fashion by X-ray crystallography and <sup>1</sup>H NMR.