10.1021/cg201170w.s004 Magnus T. Johnson Magnus T. Johnson Zoran Džolić Zoran Džolić Mario Cetina Mario Cetina Ola F. Wendt Ola F. Wendt Lars Öhrström Lars Öhrström Kari Rissanen Kari Rissanen Neutral Organometallic Halogen Bond Acceptors: Halogen Bonding in Complexes of PCPPdX (X = Cl, Br, I) with Iodine (I<sub>2</sub>), 1,4-Diiodotetrafluorobenzene (F4DIBz), and 1,4-Diiodooctafluorobutane (F8DIBu) American Chemical Society 2015 halogen F 4DIBz F 8DIBu form XB complexes van der Waals radii XB donors F 4DIBz F 8DIBu iodine F 8DIBu behavior pincer palladium chloride 1 Neutral Organometallic Halogen Bond Acceptors XB interactions 2015-12-16 20:39:03 Dataset https://acs.figshare.com/articles/dataset/Neutral_Organometallic_Halogen_Bond_Acceptors_Halogen_Bonding_in_Complexes_of_PCPPdX_X_Cl_Br_I_with_Iodine_I_sub_2_sub_1_4_Diiodotetrafluorobenzene_F4DIBz_and_1_4_Diiodooctafluorobutane_F8DIBu_/2017818 The behavior of a sterically crowded neutral pincer {2,6-bis­[(di-<i>t</i>-butylphosphino)­methyl]-phenyl}palladium (PCPPd) halides, PCPPdX (X = Cl, Br or I), as XB acceptors with strong halogen bond (XB) donors, iodine (I<sub>2</sub>), 1,4-diiodotetrafluorobenzene (F4DIBz), and 1,4-diiodooctafluorobutane (F8DIBu) were studied in the solid state. The co-crystallization experiments afforded high-quality single crystals of XB complexes PCPPdCl–I<sub>2</sub> (<b>1a</b>), PCPPdBr–I<sub>2</sub> (<b>2a</b>), PCPPdI–I<sub>2</sub> (<b>3a</b>), PCPPdCl–F4DIBz (<b>1b</b>), PCPPdBr–F4DIBz (<b>2b</b>), and PCPPdBr–F8DIBu (<b>2c</b>). The 1:1 iodine complexes (<b>1a</b>, <b>2a</b>, and <b>3a</b>) all showed a strong halogen bonding interaction, the reduction of the sum of the van der Waals radii of halogen to iodine being 24.6 (<b>1a</b>), 23.9 (<b>2a</b>), and 19.4% (<b>3a</b>) with X···I–I angles of 177, 176, and 179°, respectively. While the pincer palladium chloride <b>1</b> and bromide <b>2</b> were crystallographically isomorphous and showed similar XB behavior, the palladium iodide complex, <b>3</b>, exhibited markedly different properties, and unlike <b>1</b> and <b>2</b> it does not, under similar conditions, result in XB complexes with the weaker XB donors F4DIBz and F8DIBu. The results indicate that PCPPdI is not nucleophilic enough to have XB interactions with other donors than iodine. However, the weaker XB donors F4DIBz and F8DIBu form XB complexes with the chloride <b>1</b> and especially with the bromide <b>2.</b> The prevalence of the halogen bonding with <b>2</b> is probably not only electronic in origin, and it seems to offer the best balance between electron poorness and steric availability. The XB interactions with F4DIBz and F8DIBu are much weaker than with iodine, the reduction of the sum of the van der Waals radii of halogen to iodine being 13.5, 12.3, and 14.6% with C–I···X angles between 163 and 179° for <b>1b</b>, <b>2b</b>, and <b>2c</b>, respectively, and results in polymeric (···<b>1</b>···F4DIBz···<b>1</b>···F4DIBz···)<sub><i>n</i></sub>, (···<b>2</b>···F4DIBz···<b>2</b>···F4DIBz···)<sub><i>n</i></sub>, and (···<b>2</b>···F8DIBu···<b>2</b>···F8DIBu···)<i><sub>n</sub></i> one-dimensional zigzag chains in the solid state.