Syntheses And Structures Of Three Macrocyclic Supramolecular Complexes And One Zn-Ii-Containing Coordination Polymer Generated From A Semi-Rigid Multidentate N-Containing Ligand

Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine (L), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(mu-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn2Cl4(C12H10N6)(2)]center dot 2CH(2)Cl(2), (I), the analogous chloroform monosolvate, [Zn2Cl4(C12H10N6)(2)]center dot CHCl3, (II), bis(mu-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn2I4(C12H10N6)(2)]center dot 2CH(2)Cl(2), (III), and catenapoly[[[diiodidozinc(II)]-mu-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine] chloroform monosolvate], {[ZnI2(C12H10N6)]center dot CHCl3}(n), (IV), by solution reaction with ZnX2 (X = Cl and I) in a CH2Cl2/CH3OH or CHCl3/CH3OH mixed solvent system at room temperature. Complex (I) is isomorphic with complex (III) and has a bimetallic ring possessing similar coordination environments for both of the Zn-II cations. Although complex (II) also contains a bimetallic ring, the two Zn-II cations have different coordination environments. Under the influence of the I- anion and guest CHCl3 molecule, complex (IV) displays a significantly different structure with respect to complexes (I)-(III). C-H center dot center dot center dot Cl and C-H center dot center dot center dot N hydrogen bonds, and pi-pi stacking or C-Cl center dot center dot center dot pi interactions exist in complexes (I)-(IV), and these weak interactions play an important role in the three-dimensional structures of (I)-(IV) in the solid state. In addition, the fluorescence properties of L and complexes (I)-(IV) were investigated.