Ligand chain length conveys thermochromism

Area of Science:

• Materials Science
• Inorganic Chemistry
• Physical Chemistry

Background:

• Thermochromic materials change color with temperature, offering potential for sensing applications.
• Previous studies focused on non-ionic copper compounds, but the role of specific ligands was less explored.

Purpose of the Study:

• To investigate the thermochromic properties of copper(II) complexes formed with primary amines (A) and alpha-linolenic acid (AL).
• To establish the relationship between ligand chain length and the observed thermochromism.
• To explore the potential of these compounds as temperature-sensing materials.

Main Methods:

• Synthesis of non-ionic copper compounds with varying ligand chain lengths.
• Characterization using physical measurements.
• Theoretical studies employing time-dependent density functional theory (TD-DFT).

Main Results:

• Copper(II) complexes with primary amines and alpha-linolenic acid exhibit thermochromic behavior.
• Thermochromism is dependent on the chain length of the amine and fatty acid ligands.
• A balanced competition between ligands for the copper(II) center drives the thermochromic effect.

Conclusions:

• The thermochromic properties of these copper compounds are tunable via ligand selection.
• The structure-property relationship was elucidated through experimental and theoretical analyses.
• These non-ionic copper compounds show promise for future temperature-sensor applications.