Halogen Bonding in Ring-Substituted Group 10 POCOP Iodido Complexes with Iodine and Its Possible Role in Oxidative Addition: Halogen Bonding in Ring-Substituted Group 10 POCOP Iodido Complexes with Iodine and Its Possible Role in Oxidative Addition

Halogen bonding (XB) of an isostructural series of complexes of the type [3,5-tBu(tBuPOCOPtBu)MI] [3,5-tBu(2)(tBuPOCOPtBu) = (3)-C6H-3,5-(tBu)(2)-2,6-(OPtBu2)(2); M = Ni, Pd, Pt] with iodine as XB donor was studied in the solid state. Co-crystallization experiments afforded single crystals for all three XB systems [3,5-tBu(tBuPOCOPtBu)NiI] (1-I-2), [3,5-tBu(tBuPOCOPtBu)PdI] (2-I-2), and [3,5-tBu(tBuPOCOPtBu)PtI] (3-I-2). Whereas in the case of 1-I-2, two molecules of I-2 bind to the iodide ligand, complexes 2-I-2 and 3-I-2 are isostructural 1:1 adducts with almost orthogonal binding of I-2 to the metal iodido acceptor. All adducts form zig-zag chain structures where the pincer complexes act as bifunctional XB acceptors, forming XB interactions between metal iodide ligand and I-2 as well as between the aryl backbone of the pincer ligand and the I-2 XB donor. DFT studies were performed to analyze the electronic structure of the XB adducts. Halogen bonded adducts and related products of I-2 coordination were examined as formal intermediates in oxidative addition of I-2 to a metal(II) center. Computational data suggest that the herein described complexes do not play a role in this context.