Synthesis, crystal structures and luminescence properties of seven mononuclear zinc(II), cadmium(II), cobalt(II) and nickel(II) complexes with 5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole

摘要

Due to their versatile coordination modes and metal-binding conformations, triazolyl ligands can provide a wide range of possibilities for the construction of supramolecular structures. Seven mononuclear transition metal complexes with different structural forms, namely aquabis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ~2N~1,N~5]zinc(II), [Zn(C_14H_11N_4)_2(H_2O)], (I), bis[5-(4-methyl-phenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole-κ~2N~3,N~4]bis(nitrato-κO)zinc(II), [Zn-(NO_3)_2(C_14H_12N_4)_2], (II), bis(methanol-kappaO)bis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ~2N~1,N~5]zinc(II), [Zn(C_14H_11N_4)_2(CH_4O)_2], (III), diiodidobis[5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole-κ~2N~,N~4]cad-mium(II), [CdI_2(C_14H_12N_4)_2], (IV), bis[5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole-κ~2N~3,N~4]bis(nitrato-kappaO)cadmium(II), [Cd(NO_3)_2(C_14H_12N_4)_2], (V), aquabis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ~2N~1,N~5]-cobalt(II), [Co(C_14H_11N_4)_2(H_2O)], (VI), and diaquabis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ~2N~1N~5]nickel(II), [Ni(C_14H_11N_4)_2(H_2O)_2], (VII), have been prepared by the reaction of transition metal salts (Zn~II, Cd~II, Co~II and Ni~II) with 3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazole (pymphtzH) under either ambient or hydrothermal conditions. These compounds have been characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. All the complexes form three-dimensional supramolecular structures through hydrogen bonds or through pi-pi stacking interactions between the centroids of the pyridyl or arene rings. The pymphtzH and pymphtz~- entities act as bidentate coordinating ligands in each structure. Moreover, all the pyridyl N atoms are coordinated to metal atoms (Zn, Cd, Co or Ni). The N atom in the 4-position of the triazole group is coordinated to the Zn and Cd atoms in the crystal structures of (II), (IV) and (V), while the N atom in the 1-position of the triazolate group is coordinated to the Zn, Co and Ni atoms in (I), (III), (VI) and (VII).