Verstile silver(I) and nickel(II) NHC complexes bearing benzotriazole-function: Synthesis, fluorescence and catalytic property

Abstract

The imidazolium salts [(N-alkyl-imidazolyl) methyl] benzotriazole hexafluorophosphate (L1H: alkyl = n-C4H9, L2H: alkyl = picoly, L3H: alkyl = 9-anthrylmethyl, L4H: alkyl = 1-naphthylmethyl) have been prepared. Mononuclear N-Heterocyclic carbene silver complexes: L1AgPF6 (1), L2AgPF6 (2), L3AgPF6 (3) were synthesized in DMSO. Transmetalation reactions afford the synthesis of the nickel(II) complex L2Ni(PF6)2 (4). Furthermore, L2H, L3H and L4H were treated with silver oxide in CH3CN to afford other complexes (5, 6 and 7). The complexes 5 and 6 formed 1D and 2D supramolecular chains by AgN bond and intermolecular π-π interactions, respectively, which were found that the carbene carbon atoms of NHCs are not coordinated to silver atom. However, in Complex 7, silver atoms selectly bind to nitrogen atoms of benzotriazoles and carbon atoms of imidazoles, which afford the dinuclear Ag metallamacrocycles. Complexes 1–7 were characterized by single crystal X-ray diffraction, NMR spectroscopy, elemental analysis and powder X-ray diffraction. The catalytic activity of NHCNi complex 4 for Suzuki−Miyaura cross-coupling was studied.