Silver(I), mercury(II) and palladium(II) complexes of functionalized N-heterocyclic carbenes: Synthesis, structural studies and catalytic activity

摘要

A series of NHC silver(I), mercury(II) and palladium(II) complexes, [(1,3-diethylbimy)_6Ag_4I_3]I (2), [(1-benzyl-3-picolylbimy)Ag_2Br_2]_n (3), [(1-benzyl-3-picolylbimy)HgI(CH_2CN)]_2 (4), {[(1-picolyl-3-npropylbimy)_2Hg][Hg_2I_6]} _n (5) and [(1,3-dipicolylbimy)PdCl]Cl (6), as well as one anionic complex [1,3-diethylbimidazolium]_2[HgI_4] (1) (bimy = benzimidazol-2-ylidene), have been prepared and characterized. Interestingly, a wind wheel-like Ag_4I_3 arrangement in 2 is formed, 1D polymeric chain containing 12-membered macrometallocycles and quadrangle Ag _2Br_2 units in 3 is generated, and the α-carbon atom of deprotonated acetonitrile ([CH_2CN]~-) in 4 participates in coordination with mercury(II) atom. In the crystal packings of complexes 1-6, 2D supramolecular layers or 3D supramolecular architectures are formed via intermolecular weak interactions, including π-π interactions, hydrogen bonds, C-H?π contacts, weak Hg?I bonds and I?I bonds. Additionally, the catalytic activity of the NHC palladium(II) complex 6 in Suzuki-Miyaura cross-coupling reaction was studied.