A novel mononuclear square-planar copper(II) complex (Pip-H+)2[CuL4]2− with 2-cyano-3-(2,5-dimethoxyphenyl)acrylic acid as ligand: synthesis, crystal structures, spectral and thermal studies

Abstract

2-Cyano-3-(2,5-dimethoxyphenyl)acrylic acid and its novel mononuclear square-planar copper(II) complex dipiperidinium tetrakis[2-cyano-3-(2,5-dimethoxyphenyl)acrylic acid]copper(II) ((Pip-H+)2[CuL4]2−) were synthesized and characterized by elemental analyses, FT–IR, UV–Vis spectroscopy, and thermogravimetric analysis. Moreover, the ligand was characterized by 1H and 13C NMR spectroscopy. The structures of the ligand and its copper(II) complex were confirmed by single-crystal X-ray crystallography. Whereas the ligand crystallizes in the triclinic space group Pī with unit cell parameters a = 4.6911(2) A, b = 9.0181(4) A, c = 13.7084(6) A, α = 74.946(4)°, β = 87.152(4)°, γ = 89.220(4)°, V = 559.34(4) A3, and Z = 2, the complex crystallizes in the orthorhombic space group Pccn with unit cell parameters a = 27.5486(5) A, b = 12.9484(2) A, c = 15.8822(3) A, V = 5,665.34(17) A3, and Z = 4.