Crystal structure, spectroscopic studies, and nonlinear optical (NLO) properties of Schiff base metal complexes containing an N, S donor ligand

Abstract

A new ligand, 4-dipropylaminobenzaldehyde thiosemicarbazone (abbreviated as HL), and its complexes ML2 (M = Ni, Pd, and Cu) have been synthesized and fully characterized by elemental analyses, EI-MS, IR and UV–vis spectroscopy, and photoluminescence measurements. All of the compounds exhibit a blue–green color with dual fluorescence in DMF solution. The quantum yield ratio (Φ′(CT)/Φ(LE)) decreases in the order NiL2 > HL > PdL2 > CuL2. The ligand HL crystallizes in the monoclinic system, space group P21/n, with a = 15.1680, b = 8.5573, and c = 25.3920 Å, β = 100.3457°, and V = 3242.2 Å3. The nickel complex (NiL2) crystallizes in the triclinic system, space group Pī, with a = 8.3093, b = 9.7540, and c = 10.2802 Å, α = 101.383°, β = 107.693°, γ = 96.703°, and V = 764.12 Å3. In these complexes, HL has lost a proton from its tautometric thiol form and acts as a single negatively charged bidentate ligand coordinating to the nickel ion via the mercapto sulfur and β-nitrogen atoms. The geometry around Ni(II) is almost square-planar with two equivalent Ni—N and two equivalent Ni—S bonds. The monomeric structure of HL or NiL2 is extended into an infinite two-dimensional network via hydrogen bonds. The two-photon absorption of HL and ML2 solutions (in DMF) was measured at 532 nm by the open-aperture Z-scan technique. Key words: crystal structure, metal complex, dual fluorescence, NLO.

Synthesis, Characterization and Third Order Non Linear Optical Properties of Metallo Organic Chromophores

“…Crystal structure, spectroscopic studies, and nonlinear optical (NLO) properties of Schiff base metal complexes containing an N, S donor ligand have been studied by Zhao-Ming Xue et al [11]. Third-order nonlinear optical properties of nickel(II) and copper(II) complexes with salen ligands, functionalized with electron donor/acceptor groups (DA-salen), have been investigated in solution by the Z-scan technique using an Nd:YAG laser (1064 nm).…”

Preparation, characterization, two-photon absorption and optical limiting properties of a novel metal complex containing carbazole

“…However, most of these materials are organic compounds or polymers and the low melting points or decomposition temperatures inhibit their applications. The metal complexes with strong two-photon absorption are seldom studied [9]. By carefully selecting the organic components, one hopes to tune the physical properties of compounds by tailoring their structures and realize various applications.…”

“…In order to seek new nonlinear optical (NLO) materials of metal complexes, we have initiated studies on new chelating ligands of carbazole derivatives containing the p-electron delocalized systems and mixed NS donors [9,[13][14][15][16] in an attempt to examine their modes of binding and possible properties. We report here our new improvement in the synthesis and crystal structure of a metal complex with high thermal stability of the novel Schiff base ligand (HL) derived from S-methyldithiocarbazate and N-ethyl-3-formylcarbazole.…”