화학공학소재연구정보센터
Inorganic Chemistry, Vol.53, No.8, 4029-4038, 2014
A Ditopic O4S2 Macrocycle and Its Hard, Soft, and Hard/Soft Metal Complexes Exhibiting Endo-, Exo-, or Endo/Exocyclic Coordination: Synthesis, Crystal Structures, NMR Titration, and Physical Properties
A 20-membered O4S2 macrocycle (L-2) was synthesized as a ditopic ligating system toward hard and soft metal ions simultaneously. Five complexes (3-7) of L-2 with different structures and coordination modes, including discrete to infinite forms, mono- to heteronuclear, and endo- to exo- and endo/exocoorclination, were prepared and structurally characterized. First, the reaction of L-2 with Pb(ClO4)(2)center dot 3H(2)O afforded a typical endocyclic mononuclear perchlorato complex [Pb(L-2)(ClO4)(2)] (3) in which one lead(II) is surrounded by the macrocycle adopting a "tight and bent" conformation. Meanwhile, the reaction with a softer metal salt AgNO3 resulted in the formation of the dinuclear bis(macrocycle) complex [Ag-2(L-2)(2)(NO3)(2)] (4) in which two exocyclic silver(I) ions are doubly linked by two nitrate ions. The treatment of L2 with CuI gave a mixture of the exocyclic monomer complex [Cu(L-2)I] (5) and the exocyclic dimer complex [(Cu2I2)(L-2)(2)] (6), which were separated manually because of their brick and rhomboid shapes of the crystals, respectively. Furthermore, the reaction of L2 with a mixture of CuI and NaI afforded a photoluminescent heteronuclear complex [Na-2(Cu6I8)(L-2)(2)(CH3CN)(4)](n) (7) in the endo/exocyclic coordination mode. In this case, the endocyclic sodium(I) complex units are linked by the double-open cubanes-type cluster Cu6I8, yielding a two-dimensional network. The structural and binding properties of the complex of L-2 with silver(I) nitrate in solution were monitored by the NMR titration. Photophysical and thermal properties for complex 7 were also investigated and discussed.