Supramolecular Assembly of Metal Complexes by (Aryl)I⋅⋅⋅d[Pt^II] Halogen Bonds

Abstract

The theoretical data for the half-lantern complexes [{Pt( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover><mml:mrow><mml:mi>C</mml:mi> <mml:mi>N</mml:mi></mml:mrow> <mml:mo>^</mml:mo></mml:mover> </mml:math> )(μ- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover><mml:mrow><mml:mi>S</mml:mi> <mml:mi>N</mml:mi></mml:mrow> <mml:mo>^</mml:mo></mml:mover> </mml:math> )}₂ ] [1-3; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover><mml:mrow><mml:mi>C</mml:mi> <mml:mi>N</mml:mi></mml:mrow> <mml:mo>^</mml:mo></mml:mover> </mml:math> is cyclometalated 2-Ph-benzothiazole; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover><mml:mrow><mml:mi>S</mml:mi> <mml:mi>N</mml:mi></mml:mrow> <mml:mo>^</mml:mo></mml:mover> </mml:math> is 2-SH-pyridine (1), 2-SH-benzoxazole (2), 2-SH-tetrafluorobenzothiazole (3)] indicate that the Pt⋅⋅⋅Pt orbital interaction increases the nucleophilicity of the outer d <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow></mml:mrow> <mml:mrow><mml:mi>z</mml:mi> <mml:msup><mml:mrow></mml:mrow> <mml:mn>2</mml:mn></mml:msup> </mml:mrow> </mml:msub> </mml:math> orbitals to provide assembly with electrophilic species. Complexes 1-3 were co-crystallized with bifunctional halogen bonding (XB) donors to give adducts (1-3)₂ ⋅(1,4-diiodotetrafluorobenzene) and infinite polymeric [1⋅1,1'-diiodoperfluorodiphenyl]_n . X-ray crystallography revealed that the supramolecular assembly is achieved through (Aryl)I⋅⋅⋅d <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow></mml:mrow> <mml:mrow><mml:mi>z</mml:mi> <mml:msup><mml:mrow></mml:mrow> <mml:mn>2</mml:mn></mml:msup> </mml:mrow> </mml:msub> </mml:math> [Pt^II ] XBs between iodine σ-holes and lone pairs of the positively charged (Pt^II )₂ centers acting as nucleophilic sites. The polymer includes a curved linear chain ⋅⋅⋅Pt₂ ⋅⋅⋅I(arene^F )I⋅⋅⋅Pt₂ ⋅⋅⋅ involving XB between iodine atoms of the perfluoroarene linkers and (Pt^II )₂ moieties. The ¹⁹⁵ Pt NMR, UV/Vis, and CV studies indicate that XB is preserved in CH(D)₂ Cl₂ solutions.