Syntheses and crystal structures of two mixed-ligand dimeric zinc complexes containing a dithiol ligand and an open chain crown ether ligand with terminal quinolyl groups

Two mixed-ligand zinc complexes Zn(L)(H2O)(mnt) (1) and Zn(L)(H2O)(i-mnt) (2) (where L=2,6-bis(8′-quinoylyloxymethyl)pyridine, mnt =1,2-dicyanoethylene-1,2-ditholate and i-mnt =1,1-dicyanoethylene-2,2-ditholate) have been synthesized and characterized by elemental analysis, FT-IR spectra, and single-crystal X-ray diffraction. Complexes 1 and 2 both crystallize in the monoclinic system, space group C2/c and each displays a distorted trigonal bipyramidal around zinc atom. The coordination sphere of Zn is NO2S2 type, where the dithiol ligand (mnt or i-mnt) and one terminal quinolyl group of L act as the chelate S, S and N, O donor sets, respectively, besides the coordination water molecules. Furthermore, there are intramolecular H-bonds occurred between the coordination water molecule and the N2, N3 atoms of the L and the molecules of 1 and 2 both form the dimers through the intermolecular π–π stacking interactions.