N-Hetercocyclic carbene metallacrown ethers based on 1,8-dihydroxy-9,10-anthraquinone: Synthesis, structures and application in situ palladium-catalyzed Suzuki–Miyaura reaction

•Synthesis and characterization of seven new NHC–Ag, NHC–Au, and NHC–Hg complexes.•NHC metal complexes contain a 16-membered or 18-membered macrometallocycle.•NHC complex 4 and PdCl2(CH3CN)2 catalyzed Suzuki–Miyaura reaction in aqua-phase.

N-Hetercocyclic carbene precursors containing 1,8-dihydroxy-9,10-anthraquinone derivative: 1,8-bis(3-(N-R-imidazole)propoxy)-9,10-anthraquinone 2X (L1H2: R = PhCH2, X = Br, L3H2: R = nBu, X = PF6, L4H2: R = PhCH2, X = PF6, L5H2: R = PyCH2, X = PF6), 1,8-bis(2-(N-R-imidazole)ethoxy)-9,10-anthraquinone 2X (L2H2: R = PhCH2, X = PF6) and 1,8-bis(3-(N-R-imidazole)propoxy)anthracene 2X (L6H2: R = PhCH2, X = PF6) were synthesized. N-Heterocyclic carbene metallacrown ethers: L1AgBr (1), L2AgPF6 (2), L3AgPF6 (3), L4AgPF6 (4), L6AgPF6 (5), L4AuPF6 (6), L5Hg(PF6)2 (7) have been prepared. Complexes 1–7 were characterized by elemental analysis, NMR spectroscopy and single crystal X-ray diffraction. Particularly, complex 4 and PdCl2(CH3CN)2 synergetically and efficiently catalyzed in situ Suzuki–Miyaura cross-coupling reaction in 100% aqua-phase.

Graphical abstractSeven N-hetercocyclic carbene metallacrown ether containing 1,8-dihydroxy-9,10-anthraquinone derivative complexes of silver, gold and mercury have been synthesized. New NHC complexes have been characterized by elemental analysis, NMR spectroscopy and single-crystal X-ray diffraction. Particularly, complex 4 and PdCl2(CH3CN)2 synergetically and efficiently catalyzed in situ Suzuki–Miyaura cross-coupling reaction in 100% aqua-phase.Figure optionsDownload full-size imageDownload as PowerPoint slide