Synthesis, crystal structures, and antibacterial activities of Schiff base zinc(II) complexes [Zn(L1)2] and [Zn(L2)2]

The reaction of cyclopentylamine with 2-hydroxy-1-naphthaldehyde and 5-nitrosalicylaldehyde, respectively, in methanol affords two new Schiff bases, 1-(cyclopentyliminomethyl)naphthalen-2-ol (HL1) and 4-nitro-2-(cyclopentyliminomethyl)phenol (HL2). Two new zinc(II) complexes, [Zn(L1)2] (I) and [Zn(L2)2] (II), derived from the Schiff bases, have been prepared and characterized by single-crystal X-ray diffraction, FT-IR, and elemental analysis. Complex I crystallizes in the monoclinic space group P21/c with a = 17.834(4), b = 14.738(3), c = 9.868(2) Å, β = 91.20(3)°, V = 2593.1(9) Å3, Z = 4. Complex II crystallizes in the triclinic space group P $$\bar 1$$ with a = 10.206(1), b = 10.502(1), c = 12.554(1) Å, α = 66.771(2)°, β = 78.133(2)°, γ = 76.292(2)°, V = 1191.8(1) Å3, Z = 2. The Zn atom in each complex is coordinated by two N and two O atoms from two Schiff base ligands, forming a tetrahedral geometry. The Schiff bases and the complexes were assayed for antibacterial activities.