A highly selective colorimetric and fluorescent probe Eu(tdl)2abp for H2S sensing: Application in live cell imaging and natural water

Using 4-([2,2 & PRIME;: 6 & PRIME;, 2 & PRIME;- terpyridin] -4 & PRIME;-yl)-N, N-dimethylaniline (tdl) as auxiliary ligand and 6-azido-2,2 & PRIME;-bipyr-idine (abp) as recognition ligand, a europium complex fluorescent probe Eu(4-([2,2 & PRIME;: 6 & PRIME;, 2 & PRIME;-terpyridin]-4 & PRIME;-yl)-N, N-dimethylaniline)2-6-azido-2,2 & PRIME;-bipyridine Eu(tdl)2abp for efficient and specific recognition of hydrogen sul-fide (H2S) was successfully synthesized and characterized by NMR and MS. Eu(tdl)2abp represented on-off fluorescence signals for H2S and its color changes could be identified with naked eyes. Eu(tdl)2abp had short response time (2 min) to H2S, high selectivity and good anti-interference, large stokes shift (207 nm). In various samples, when H2S existed, the azide group was reduced to amine group, resulting in closed fluorescence signal, and the fluorescence intensity reached the degree of quenching without being affected by other interference. At the same time, there was a good linear relationship between relative fluorescence intensity and H2S concen-tration with the detection limit (LOD) of 0.64 mu M. The sensing mechanism of Eu(tdl)2abp to detect H2S was characterized by 1H NMR and HR-MS. Eu(tdl)2abp was used with success for the sensitive detection of H2S in natural water and living cells.

Automated summary

In this study, a new europium complex fluorescent probe Eu(tdl)2abp was successfully synthesized for efficient and specific recognition of hydrogen sulfide (H2S). The probe exhibited on-off fluorescence signals for H2S and its color changes could be observed with naked eyes. Eu(tdl)2abp showed a short response time, high selectivity, good anti-interference, and a large Stokes shift. The probe demonstrated a linear relationship between relative fluorescence intensity and H2S concentration with a low detection limit. The mechanism of H2S detection using Eu(tdl)2abp was characterized and the probe was successfully applied in the detection of H2S in natural water and living cells.