Fluorescent salen-type Zn(II) Complexes As Probes for Detecting Hydrogen Sulfide and Its Anion: Bioimaging Applications

Abstract

In this work, we investigate the mode of interaction of a family of fluorescent zinc complexes with HS − and H 2 S. Different experiments, performed by diverse spectroscopic techniques, provide evidence that HS − binds the zinc center of all the complexes under investigation. Treatment with neutral H 2 S exhibits a markedly different reactivity which indicates selectivity for HS − over H 2 S of the systems under investigation. Striking color changes, visible to the naked eye, occur when treating the systems with HS − or by an H 2 S flow. Accordingly, also the fluorescence is modulated by the presence of HS − , with the possible formation of multiple adducts. The results highlight the potential of the devised systems to be implemented as HS − / H 2 S colorimetric and fluorescent sensors. Bioimaging experiments indicate the potential of using this class of compounds as probes for the detection of H 2 S in living cells.

Deaggregation properties and transmetalation studies of a zinc(ii) salen-type Schiff-base complex

“…[24][25][26][27][28][29] Among Zn(salen)-type complexes, colourful derivatives from the 2,3-diaminomaleonitrile, Zn(salmal), are certainly those more interesting for their optical absorption and fluorescence emission properties upon deaggregation. [30][31][32][33][34][35][36][37] In order to further explore these varied characteristics, we have chosen a Zn(salmal) complex, 1, having different substituents on the salicylidene rings. In particular, we found that the presence of 5-tert-butyl-bulky substituents makes this complex sufficiently soluble in a range of coordinating/non-coordinating solvents, giving us the possibility to explore its spectroscopic properties in solution, even in comparison to previous studies on amphiphilic Zn(salmal) complexes with longer alkyl substituents.…”

A simple approach based on transmetalation for the selective and sensitive colorimetric/fluorometric detection of copper(ii) ions in drinking water

“…[44][45][46] In particular, derivatives from the 2,3-diaminomaleonitrile, Zn(salmal), are characterized by relevant optical spectroscopic changes in relation of the nature of the aggregate species or monomeric adducts. [47][48][49][50][51][52][53] We have demonstrated that in solution of weak coordinating solvents a 5-tert-butyl substituted Zn(salmal) complex (1) forms relatively stable adducts which easily transmetalate with divalent ions of the first transition series, but with a different rate. 54 In particular, the transmetalation with Cu 2+ ions is faster than that with other cations, regardless of the nature of the counteranion.…”

Quenched Lewis Acidity: Studies on the Medium Dependent Fluorescence of Zinc(II) Complexes

“…[ 8b , 8d ] This effect was used previously for bioimaging and biosensing in living cells. [ 8c , 8g , 9 ] Furthermore, derivatives of this zinc(II) complex type were investigated for their mechanochromic luminescence behavior, and as emitters for optical temperature sensing via thermally activated delayed fluorescence (TADF). [10]…”