Chair- and Boat-configurations of silver(I) complexes of ditopic ligand involving benzimidazolyl substituents

The ditopic ligand 1,2-bis(benzimidazol-1-ylmethyl)benzene (L1) as well as its silver(I) complexes [Ag2L12(CF3CO2) 2] (1) and [Ag2L12](CF3SO3) 2·(L1)·2H2O·0.5C 2H5OH (2) were prepared and structures characterized by X-ray crystallography. The Ag1 atoms in 1 are trigonally coordinated by two NBIm atoms from the arms of L1 and by one O atom of the anion CF3CO2-, while those in 2 are only linearly ligated by NBIm. Different silver salts of CF3CO2- and CF3SO3- lead to different configurations of the dimeric unit [Ag2L12]2+: chair-form in (1) but boat-form in (2). The discrete molecules in both 1 and 2 are assembled into network structures through face-to-face π⋯π stacking and edge-to-face C-H⋯π interactions in the crystalline state, as well as N-H⋯O and C-H⋯O hydrogen bonds. Solution 1H NMR studies showed the formation of one sole species in solution or a rapid equilibrium was established on the NMR time scale at room temperature.Department of Applied Biology and Chemical Technolog