Self assembly of a tren-derivative hydrogenated Schiff base with transition metal ions: syntheses, crystal structures and photoluminescent properties

Abstract

A new flexible multidentate hydrogenated Schiff base tris{2-[(4′-pyridylmethyl)amino]ethyl}amine (L), derived from tren (tris(2-aminoethyl)amine) and 4-pyridinecarboxaldehyde, has been used to prepare four novel complexes 1–4. Complex {[Zn_1.5L(H₂O)₃](NO₃)₃·2.5H₂O}₂ (1) exhibits a mononuclear zero-dimensional structure. Complex {[Cd₂LCl₄(H₂O)]·H₂O}_n (2) shows a one-dimensional meso-helical structure which consists of two adjacent hydrogen-bonded three-stranded single-helical (P and M) chains. Intermolecular CH (or NH)⋯Cl hydrogen bonds play important roles in the formation of the triple helices and meso-helical structure. Complexes {[Cd_1.5L(NO₃)₂(H₂O)]NO₃·2H₂O}_n (3) and {[Mn_1.5LCl₂(H₂O)]Cl·6H₂O}_n (4) display similar 2D layer networks, which are composed of alternate right-handed and left-handed helical chains by sharing Cd or Mn ions. Moreover, the photoluminescence of complexes 1–3 have also been investigated in the solid state.