Synthesis, structure, and antibacterial properties of ternary rare-earth complexes with o-methylbenzoic Acid and 1,10-phenanthroline

Abstract

Ternary rare-earth complexes with o-methylbenzoic acid (o-MBA) and 1,10-phenanthroline (Phen) Ln2(o-MBA)6(Phen)2 · nH2O(n = 0, 1) (Ln = La, Pr, Y, Yb) were synthesized and characterized by elemental analysis, IR, X-ray diffraction, and TG-DTG means. The complex La2(o-MBA)6(Phen)2 · H2O (I) is composed of two species of binuclear molecules in which the La3+ ion is coordinated with two nitrogen atoms of Phen and seven oxygen atoms of carboxylate groups. The carboxylate groups were bonded to La3+ in three modes: chelating-bidentate, bridging-bidentate, and chelating-bridging tridentate. The La3+ ion adopted a vigorous distorted monocapped square antiprism geometry. Complex I belongs to the triclinic crystal system, P space group, lattice parameters: a = 13.058(3), b = 12.7584(11), c = 20.773(4) A, α = 101.18(3)°, β = 93.88(3)°, γ = 115.82(3)°, V = 3283.0(11)A3, Z = 2, ρcalcd = 1.484 mg/m3, Mr = 1467.06, F(000) = 1476, μ = 1.350 mm-1. The structure was refined to Rl = 0.0631 and wR2 = 0.1504. The antibacterial activity test indicates that these complexes exhibit better antibacterial ability against Escherichia coli and Staphylococcus aureus than the corresponding rare-earth chloride or o-MBA.