Variation in crystalline architectures through supramolecular interactions in copper(II) complexes with tridentate N₂O donor Schiff bases

<div><p>Three copper(II) complexes, [Cu(L¹)(H₂O)(ClO₄)]·0.5H₂O (<b>1</b>), [Cu(L²)(H₂O)(ClO₄)]·0.5H₂O (<b>2</b>), and [Cu(L²)(NCNC(OCH₃)NH₂)]ClO₄ (<b>3</b>), where HL¹ = 4-bromo-2-(-(quinolin-8-ylimino)methyl)phenol and HL² = 1-(-(quinolin-8-ylimino)methyl)naphthalen-2-ol, have been prepared and characterized by elemental analysis, IR, UV–vis and fluorescence spectroscopy and single-crystal X-ray diffraction studies. The copper(II) centers assume five-coordinate square-pyramidal geometries in <b>1</b> and <b>2</b>, whereas square planar copper(II) is present in <b>3</b>. A methanol molecule has been inserted in the pendant end of the ligated dicyanamide in <b>3</b>. Various supramolecular architectures are formed by hydrogen bonding, <i>π</i>⋯<i>π</i>, C–H⋯<i>π</i>, and lp⋯<i>π</i> interactions.</p>