Synthetic and single-crystal X-ray diffraction studies of CH2I2 and aryl iodide complexes of silver carboxylates and β-diketonates

Abstract

The silver(I) iodocarbon complexes [{Ag₂(O₂CCF₃)₂(CH₂I₂)₂}_n] 1, [{Ag₂(O₂CCF₃)₂(1,2-I₂C₆H₄)₂}_n] 2, [{Ag₂(O₂CCF₃)₂(1,4-I₂C₆H₄)₂}_n] 3, [{Ag₂(O₂CCF₃)₂(IC₆H₅)}_n] 4, [{Ag₄(O₂CCF₃)₄(H₂O)₂(p-IC₆H₄Me)₂}_n] 5, [{Ag₂(O₂CCF₃)₂(1,2-I₂C₆H₄)}_n] 6, [{Ag₂(O₂CCCl₃)₂(HO₂CCCl₃)(1,2-I₂C₆H₄)}_n] 7, [{Ag₂(O₂CCCl₃)₂(HO₂CCCl₃)(IC₆H₅)}_n] 8, [{Ag₄(hfacac)₄(p-IC₆H₄Me)₂] 10 (hfacac = 1,1,1,5,5,5-hexafluoroaceylacetonate) and [Ag₄(hfacac)₄(1,2-I₂C₆H₄)₃] 11 have been prepared and structurally characterized by single-crystal X-ray diffraction. The silver carboxylate complexes all contain carboxylate-bridged Ag₂(carboxylate-O,O′)₂ dimers (Ag–O 2.22–2.40 Å) with the intradimer Ag· · ·Ag distance varying in the range 2.9106(12) to 3.1527(14) Å which are the values observed for the alternating dimer units Ag₂(O₂CCF₃)₂(H₂O)₂ and Ag₂(O₂CCF₃)₂ observed in 5. In the complexes 1–3 the silver trifluoroacetate dimers are linked by I,I′-bridging I₂R ligands with one ‘short’ Ag–I bond (2.94–3.05 Å) and one ‘long’ Ag–I bond (3.13–3.14 Å) per silver. In 4, 7 and 8 the Ag₂(carboxylate-O,O′)₂ dimers are extended into a chain polymer via Ag₂O₂ rings formed by co-ordination of each silver to an oxygen atom (Ag–O 2.33–2.51 Å) from an adjacent dimer. The 1,2-I₂C₆H₄ forms an I,I′ bridge across the two silver atoms of the dimer unit in 7 [Ag–I 2.918(1) and 3.024(1) Å]. Complex 8 contains an acute angle bridging IC₆H₅ [Ag–I 2.927(2) and 2.970(2) Å, Ag–I–Ag 61.4(1)°], whilst in 4 the IC₆H₅ is semibridging [Ag–I 2.853(1) and 3.309(1) Å]. In complex 5 the two structurally different dimer units are bridged in a wide-angle fashion by p-IC₆H₄Me [Ag–I 2.9200(9) and 2.9333(8) Å, Ag–I–Ag 144.53(3)°]. Complex 6 contains eight-atom Ag₂(O₂CCF₃-O,O′)₂ rings linked to six-atom Ag₂(O₂CCF₃-O,O′)(O₂CCF₃-O,O) rings which are interlinked to give an alternating 8646 ring chain polymer with I,I′-bridging 1,2-I₂C₆H₄ across the two silvers of the six-atom rings [Ag–I 2.722(2) and 2.980(2) Å]. The hfacac complex 10 contains a tetranuclear unit in which the hfacac ligands both chelate and bridge whilst the p-iodotoluenes each bridge two silvers via η¹-iodocarbon and η²-aryl co-ordination. Complex 11 is a tetranuclear unit in which three hfacac ligands both chelate and bridge whilst the fourth hfacac ligand bridges two silvers and forms a monodentate interaction with a third silver in a µ-O, η¹-O′ mode. One 1,2-I₂C₆H₄ ligand forms a monodentate interaction with a silver atom [Ag–I 3.064(3) Å] whilst the other two 1,2-I₂C₆H₄ molecules function as highly unsymmetrical bidentate ligands [Ag–I 2.691(2), 3.350(2) and 2.719(2) and 3.228(2) Å]. The Ag–I–C bond angles vary from 85.9(4)° in 11 to 108.70(12)° in 3.