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

A series of NHC silver(I), mercury(II) and palladium(II) complexes, [(1,3-diethylbimy)(6)Ag4I3]I (2), [(1-benzyl-3-picolylbimy)Ag2Br2](n) (3), [(1-benzyl-3-picolylbimy)HgI(CH2CN)](2) (4), {[(1-picolyl-3-npropylbimy)(2)Hg][Hg2I6]}(n) (5) and [(1,3-dipicolylbimy)PdCl] Cl (6), as well as one anionic complex [1,3-diethylbimidazolium](2)[HgI4] (1) (bimy = benzimidazol-2-ylidene), have been prepared and characterized. Interestingly, a wind wheel-like Ag4I3 arrangement in 2 is formed, 1D polymeric chain containing 12-membered macrometallocycles and quadrangle Ag2Br2 units in 3 is generated, and the alpha-carbon atom of deprotonated acetonitrile ([CH2CN]) 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 pi-pi interactions, hydrogen bonds, C-H center dot center dot center dot pi contacts, weak Hg center dot center dot center dot I bonds and I center dot center dot center dot I bonds. Additionally, the catalytic activity of the NHC palladium(II) complex 6 in Suzuki-Miyaura cross-coupling reaction was studied. (C) 2011 Elsevier B.V. All rights reserved.