Copper(II) complexes with tridentate N2O donor Schiff bases: Modulation of crystalline architectures through supramolecular interactions

Three mononuclear copper(II) complexes, [Cu(L1)(DMF)]ClO4 (1), [Cu(L2)(DMSO)]ClO4 (2) and [CuL3(NCO)] (3) (where HL1 {2-[(2-methylamino-ethylimino)-methyl]-4-nitro-phenol}, HL2 {2-[(2-ethylamino-ethylimino)-methyl]-4-nitro-phenol} and HL3 {2-[(2-(dimethylamino)ethylimino)methyl]-4-nitrophenol} are tridentate Schiff-base ligands), have been synthesized and characterized by elemental analysis, IR and UV–Vis spectroscopy and single-crystal X-ray diffraction studies. All the complexes are square planar. Complex 1 crystallizes in the triclinic space group, P1¯, with cell dimensions a = 8.0396(2), b = 9.0892(2), c = 12.9977(3) Å, α = 85.591(1)°, β = 84.198(1)° and γ = 76.423(1)°, whereas complex 2 crystallizes in the orthorhombic space group, Pbca with cell dimensions a = 8.4615(4), b = 17.2708(11) and c = 25.8517(12) Å. Complex 3 crystallizes in the monoclinic space group, P21/n with cell dimensions a = 6.9550(3), b = 13.2257(7), c = 14.7755(6) Å and β = 102.697(3)°. Both HL1 and HL2 are capable of forming H bonds due to the presence of H atoms in their amine groups. On the other hand, HL3 cannot form H-bonds. The weak forces like H-bonding, lone pair⋯π and π⋯π interactions lead to various supramolecular architectures in the complexes.

Three mononuclear copper(II) complexes have been synthesized and characterized by elemental analysis, IR and UV–Vis spectroscopy and X-ray crystallography. All the complexes are monomeric. The copper(II) centre assumes a square planar geometry in each of the complexes. Weak forces like H-bonding, lone pair⋯π and π⋯π interactions lead to various supramolecular architectures.Figure optionsDownload as PowerPoint slide