Three zinc iodide complexes based on phosphane ligands: syntheses, structures, optical properties and TD-DFT...

Area of Science:

• Coordination Chemistry
• Materials Science
• Solid-State Chemistry

Background:

• Phosphane ligands are crucial in synthesizing metal complexes with diverse applications.
• Zinc iodide complexes offer tunable properties for materials science.
• Understanding structure-property relationships is key for developing new functional materials.

Purpose of the Study:

• To synthesize and characterize novel zinc iodide complexes using phosphane ligands.
• To investigate the structural, optical, and thermal properties of the synthesized complexes.
• To explore the potential of these complexes as second-order nonlinear optical (NLO) materials.

Main Methods:

• Synthesis of three zinc iodide complexes: [ZnI2(PPh3)2] (1), [ZnI2(P(p-tolyl)3)2] (2), and [Zn(dppmO2)3][ZnI4] (3).
• Single-crystal X-ray diffraction for structural determination.
• UV-Vis absorption, photoluminescence spectroscopy, and thermal stability analysis.
• Time-dependent density functional theory (TD-DFT) calculations.

Main Results:

• Complexes (1) and (2) are mononuclear four-coordinated ZnI2 complexes with monodentate phosphane ligands.
• Complex (2) unexpectedly forms an acentric structure, suggesting potential second-order NLO properties.
• Complex (3) features a [Zn(dppmO2)3]2+ cation and a [ZnI4]2- anion.
• TD-DFT calculations confirm that UV absorption and light emission originate from halide-ligand charge-transfer (XLCT) states.

Conclusions:

• The synthesized zinc iodide complexes exhibit distinct structural characteristics.
• Complex (2) shows promise as a second-order NLO material due to its acentric crystal structure.
• The photophysical properties are attributed to XLCT transitions, providing insights for designing related materials.