Detection of aqueous and gaseous hydrogen sulfide with lanthanide-macrocycle binary complexes

Area of Science:

• Coordination Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Hydrogen sulfide (H2S) is a crucial signaling molecule in biological systems and an environmental pollutant.
• Accurate and sensitive detection of H2S is essential for both environmental monitoring and biological studies.
• Existing H2S detection methods often face challenges with selectivity, sensitivity, or stability.

Purpose of the Study:

• To develop novel discrete lanthanide-macrocycle binary complexes for hydrogen sulfide detection.
• To investigate the sensing mechanism based on copper sequestration.
• To evaluate the selectivity, sensitivity, and reversibility of the developed complexes for H2S detection.

Main Methods:

• Synthesis of two novel lanthanide-macrocycle binary complexes incorporating Eu3+ and Tb3+ ions.
• Utilizing a copper sequestration mechanism at a secondary binding site for H2S detection.
• Characterization of the bimetallic lanthanide(III)/copper(II) complexes.
• Testing the selectivity, sensitivity, and reversibility of the complexes for aqueous and gaseous H2S.

Main Results:

• The bimetallic complexes exhibited high selectivity, good sensitivity, and excellent reversibility for aqueous hydrogen sulfide.
• The inclusion of the DO2A macrocycle and a specific dipicolinic acid ligand enhanced solubility and stability.
• The europium(III) complex demonstrated a low limit of detection (665 ppb) and a rapid response time (30 seconds) for gaseous H2S.

Conclusions:

• The novel lanthanide-macrocycle complexes are effective sensors for hydrogen sulfide.
• Improved water solubility and stability make these sensors suitable for practical applications.
• These sensors hold significant potential for environmental monitoring and biological studies.