Synthesis and study of two Iron(II) 1,2,4-Triazole-based coordination complexes with Bistriflimide counterions towards ammonia detection

Details

Supervisors

Garcia, Yann

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences agronomiques, à finalité spécialisée

Abstract

This dissertation addresses the development of colorimetric sensing materials for gaseous ammonia (NH₃), a target of growing importance in environmental monitoring, industrial safety, agriculture, and foodfreshness assessment (via total volatile basic nitrogen, TVB-N, indicators). The approach relies on spin-crossover (SCO) coordination polymers of iron(II), in which switching between the high-spin and lowspin states is accompanied by a macroscopic colour change (vapochromism) upon exposure to guest molecules such as NH₃. Two triazole-based systems were investigated: Fe(NH₂trz)₃ and a hyetrz-based analogue. Their synthesis was characterised by elemental analysis (ICP-OES, CHNS/O), infrared spectroscopy, and powder X-ray diffraction, complemented by differential scanning calorimetry (DSC) and SQUID magnetometry to probe the thermal behaviour of the spin transition. A qualitative test for ammoniac detection has been successufly made for both triazole-based system showing the potential of these compounds, and the necessity of further investigation. This work contributes to understanding the coupling between spin-state switching and guest-induced lattice perturbation, and supports the potential use of these materials as low-cost colorimetric ammonia sensors