Sol-Gel Dipping Devices for H2S Visualization

Abstract

In this contribution we report the synthesis and full characterization, via a combination of different spectroscopies (e.g., 1H NMR, UV-vis, fluorescence, MALDI), of a new family of fluorescent zinc complexes with extended π-conjugated systems, with the final aim of setting up higher performance H2S sensing devices. Immobilization of the systems into a polymeric matrix for use in a solid-state portable device was also explored. The results provided proof-of-principle that the title complexes could be successfully implemented in a fast, simple and cost-effective H2S sensing device.

Stimuli-Responsive Properties of a Zinc(II) Salen-Type Schiff-Base Complex and Vapochromic Detection of Volatile Organic Compounds

“…In summary, the variegated vapochromic response of the cast films of 1 (Scheme ) represents a unique feature in the panorama of stimuli-responsive Zn­(II) molecular materials. − ,− In fact, the possibility to detect various VOCs having Lewis basicity, and in particular, the discrimination of primary aliphatic amines and pyridine, represents a clear advance compared to our previous work , and to other vapochromic investigations, the latter mostly related to acidochromism. − …”

“…To further explore the responsive behavior of Zn(salen)type molecular materials toward volatile Lewis bases, we chose the Zn(salmal) derivative, 1, having the 5,5′-tert-butyl-bulky substituent on the salicylidene rings, allowing comparison with previous investigated complexes 27 −29,31 having different substituents and substitution patterns. This complex was found to possess unique thermochromic and vapochromic characteristics, compared to those of our previous investigations 29,31 and literature studies on stimuli-responsive molecular materials of Zn(II) coordination complexes, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]30 allowing the detection of various VOCs having Lewis basicity and, among them, the discrimination of primary aliphatic amines and pyridine.…”

“…In this regard, Zn­(II) metal complexes and Zn­(II) coordination polymers represent an interesting family of stimuli-responsive materials, − although most of these studies refer to their mechanochromic and acidochromic properties, the latter mainly related to the chromic response when exposed to hydrochloric acid or ammonia vapors. Analogously, Zn­(salen)-type complexes, in the absence of coordinating species, form molecular aggregates via intermolecular Zn···O interactions − and are characterized by multiresponsive behavior. − Moreover, thanks to their Lewis acidic characteristics, they are potentially suitable materials for sensing volatile Lewis bases. − However, their application as chemosensors of volatile Lewis bases is rather limited. ,, …”

Activity-Based Fluorescent Probes for Hydrogen Sulfide and Related Reactive Sulfur Species

“…Probe 923 and also related 924, which provides a fluorescent turn-off at ∼650 nm upon treatment with H 2 S, were used to develop sol−gel matrices on paper strips for both visible and fluorescence detection of H 2 S in different samples in two separate reports. 930,931 Using a similar Salalen ligand system, Strianese also reported 925, which provided a fluorescent enhancement at 480 nm and an increase in fluorescence lifetime upon treatment with H 2 S. 932 This complex was also screened with Cys and GSH, both of which provided minimal responses. Using a related approach but different ligand scaffold, Strianese also reported the imidazo-pyridine system with ligand variants 926−929, which also provide responses to H 2 S in DMSO.…”

“…This compound was subsequently used to image exogenous H 2 S in HepG2 cells (Figure ). Probe 923 and also related 924 , which provides a fluorescent turn-off at ∼650 nm upon treatment with H 2 S, were used to develop sol–gel matrices on paper strips for both visible and fluorescence detection of H 2 S in different samples in two separate reports. , Using a similar Salalen ligand system, Strianese also reported 925 , which provided a fluorescent enhancement at 480 nm and an increase in fluorescence lifetime upon treatment with H 2 S . This complex was also screened with Cys and GSH, both of which provided minimal responses.…”