Preparation and structure of three NHC metal (Ag(I) and Hg(II)) complexes as well as the selective recognition of complex 1 for dihydrogen phosphate

The preparation of three metal (Ag(I) and Hg(II)) complexes based on bis-carbene ligands and correlative three precursors H2Ln center dot(PF6)(2) (n = 1-3) were reported. In each cationic moiety of complexes 1 and 2 and the monomer of complex 3, two Ag+ (or Hg2+) ions and two L-n (n = 1-3) formed one 36-membered macrometallocycle. There existed pi-pi interactions between two naphthalenes in each cationic moiety of 1 and 2. The monomers of 3 were connected together through Hg-O bonds to form 1D chain. In the crystal packings of 1-3, two-dimensional and three-dimensional supramolecular structures were formed through C-H pi contacts and C-HF H bonds. Additionally, the recognition capacity of 1 for H2PO4- was studied via fluorescence spectra, UV/Vis spectra, HRMS, H-1 NMR titrations, and infrared (IR) spectra.