Reversible Luminescent Gels Containing Metal Complexes

Abstract

Gelators are compounds capable of solidifying various solvents and water. Organic gels, and in particular hydrogels, are interesting soft materials with many potential applications. In this paper the formation of luminescent gels in water and dimethylformamide as solvents is reported. The gels are prepared by using a carboxylate‐based aliphatic gelator (1) and a N,N′‐bis(O‐methyl‐TyrOH) oxalamide derivative (2). The gels are transparent, and form fiberlike structures in the presence of the red luminescent moiety, a EuIII hemicaged complex. The spectroscopic behavior of the complex is investigated in different solvents and when is entrapped in the gel. In order to probe the involvement of the chemical structure of the luminescent moiety in the gel network, a ruthenium complex, Ru(bpy)2(dppz)2+ (where bpy = 2,2′‐bipyridine and dppz = dipyrido[3,2‐a:2′,3′‐c]phenazine) has also been employed. The complex is in fact nonluminescent in water, while emitting when incorporated in the gel. Such “switching on” behavior is attributed to the incorporation of the complex into the lipophilic environment of gel fibers, where it is shielded from quenching by water molecules.

Supramolecular gels based on organic diacid monoamides of cholesteryl glycinate

“…It is believed that it is such an arrangement that leads to the formation of the microparticles, which are characterized by a hydrophobic surface. Similar discoveries have been reported by other groups [57]. Although FTIR spectroscopy is thought to be a powerful tool for studying hydrogen bonding interactions among gelator molecules in organic solvents, it is very difficult to obtain similar information from systems containing water.…”

Synthesis of Upconverting Hydrogel Nanocomposites Using Thiol‐Ene Click Chemistry: Template for the Formation of Dendrimer‐Like Gold Nanoparticle Assemblies

“…There are only few reports on lanthanide ion‐doped supramolecular gels. For example, europium‐complex‐based gels have been synthesized by mixing the gelators with the europium complex and their luminescence properties studied 21. Maitra et al.…”

Construction of Novel Terbium Green Emissive Gels and Their Unique Thermal Degradation Processes

“…To the best of our knowledge, very few studies of lanthanide-complex gel have been reported [9,10]. In this report, we studied four luminescent organogels based on urea derivatives N,N 0 -dioctadecylurea 1 and N-octadecylurea 2 (the structures are shown in Fig.…”

“…Luminescence gels have been reported to form through two different approaches. The one is that the gelators possess photoactive units in their chemical structures and the other is photoactive molecules being hosted in the gel network [9]. As is known to us all, lanthanide complexes can exhibit emission in organic media.…”