Three zinc(II) and cadmium(II) complexes containing 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole and polynitrile ligands: synthesis, molecular and supramolecular structures, and photoluminescence properties

摘要

Three photoluminescent complexes containing either ZnII or CdII have been synthesized and their structures determined. Bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ~2N~1,N~5]bis(dicyanamido-κN~1)zinc(II), [Zn(C_12H_10N_6)_2(C_2N_3)_2],(I), bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ~2N~1,N~5]bis(dicyanamido-κN~1)-cadmium(II), [Cd(C_12H_10N_6)_2(C_2N_3)_2], (II), and bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ~2N~1,N~5]bis(tricyanomethanido-κN~1)cadmium(II), [Cd(C_12H_10N_6)_2-(C_4N_3)_2], (III), all crystallize in the space group P1, with the metal centres lying on centres of inversion, but neither analogues (I) and (II) nor CdII complexes (II) and (III) are isomorphous. A combination of N-H??? N and C-H???N hydrogen bonds and it-it stacking interactions generates three-dimensional framework structures in (I) and (II), and a sheet structure in (III). The photoluminescence spectra of (I)-(III) indicate that the energies of the pi-pi* transitions in the coordinated triazole ligand are modified by minor changes of the ligand geometry associated with coordination to the metal centres.