Syntheses, Structure, and Properties of the Metal Complexes with 3-(2-Pyridyl)pyrazole-Based Ligands: Tuning the Complex Structures by Ligand Modifications

Abstract

In our efforts to design metal complexes with tailored structures, four 3-(2-pyridyl)pyrazole-based ligands, 8-[3-(2-pyridyl)pyrazolmethyl]quinoline (L1), 1,4-bis[3-(2-pyridyl)pyrazolyl]-trans-2-butene (L2), 2,3-bis[3-(2-pyridyl)pyrazolmethyl]quinoxaline (L3), and 1,3,5-tri[3-(2-pyridyl)pyrazolmethyl]-2,4,6-trimethylbenzene (L4), have been synthesized and characterized, and their metal complexes with CuII, NiII, CoII, and CdII ions have been prepared and structurally characterized by single-crystal X-ray diffraction. Using L1 to react with CuX2 (X = Ac-, NO3-, or ClO4-) or Cd(ClO4)2·6H2O, yielded four mononuclear complexes, [Cu(L1)2(OAc)](OAc)(H2O)6 (1) [triclinic, space group P1, a = 10.513(11) A, b = 13.875(14) A, c = 15.776(16) A, α = 70.98(2)°, β = 83.57(2)°, γ = 69.665(18)°, Z = 2], [Cu(L1)2(NO3)](NO3)(H2O)5.5 (2) [monoclinic, space group C2/c, a = 12.395(3) A, b = 26.267(6) A, c = 26.362(7) A, β = 92.635(5)°, Z = 8], [Cu(L1)2(H2O)](ClO4)2(H2O)2 (3) [orthorhombic, space group Pbca, a = 13.326(4) A, ...