A dual approach to study the key features of nickel (II) and copper (II) coordination complexes: Synthesis, crystal structure, optical and nonlinear properties

We use a dual approach comprising of experimental and computational techniques to report the syntheses and characterizations of two novel nickel (II) [Ni(L)2] (1) and copper (II) [Cu(L)2] (2) coordination complexes, which are made through the coordination of 1-(E-(2, 4-dibromophenylimino) methyl) naphthalene-2-ol (HL) ligand. Several modern techniques including experimental electronic spectroscopy, single crystal X-ray crystallography and quantum computational methods are used to characterize the isolated coordination compounds. Both the complexes display a square planar trans-[MN2O2] coordination geometry (Figure 1), whose central M (II) atoms lie on the centre of symmetry. State of the art quantum computations are performed at molecular and bulk levels to get structure-property relationships from molecule to materials. The molecular nonlinear optical (NLO) response properties including third-order polarizability (γ) are calculated using density functional theory (DFT) methods. The calculated γ amplitudes for the synthesized [Ni(L)2] (1) and [Cu(L)2] (2) complexes are found to be 444.09 × 10−36 and 567.03 × 10−36 esu, respectively. [Display omitted] •Design and synthesis of Schiff base (HL) ligand and its metal (II) complexes.•Single crystal X-ray crystallography analysis.•Dual approach comprising of experimental and computational techniques.•Nonlinear optical (NLO) response properties.•Optoelectronic properties. In the present study, we use a dual approach comprising of experimental and computational techniques to report the syntheses and characterizations of two novel nickel (II) [Ni(L)2] (1) and copper (II) [Cu(L)2] (2) coordination complexes, which are made through the coordination of 1-(E-(2, 4-dibromophenylimino) methyl) naphthalene-2-ol (HL) ligand. Several modern techniques including experimental electronic spectroscopy, single crystal X-ray crystallography and quantum computational methods are used to characterize the isolated coordination compounds. Both the complexes display a square planar trans-[MN2O2] coordination geometry, whose central M (II) atoms lie on the centre of symmetry. Complexes [Ni(L)2] (1) and [Cu(L)2] (2) crystallize in the monoclinic system of the space groups P21/c with a = 9.307(4)Å, b = 12.242(4)Å, c = 13.823(4)Å, α = 90°, β = 105.262(10)°, γ = 90° and Z = 2 for complex (1), a = 9.171(5) Å, b = 12.507(8) Å, c = 13.666(8) Å, α = 90°, β = 103.823(15)°, γ = 90°, and Z = 2 for complex (2). The ligand (HL) is coordinated as mo