Electrochemiluminescence of a Periodic Mesoporous Organosilica Containing 9,10-Diarylanthracene Units

Abstract

A 9,10-diarylanthracene derivative having two terminal trimethoxysilyl groups has been synthesized and used in combination with tetraethyl orthosilicate as a silicon source for the preparation of two periodic mesoporous silicas with MCM-41 and SBA-15 structures having about 15 wt % of the organic component. The resulting solids exhibit electrochemiluminescence arising from the organic moieties. The benefit for the electrochemiluminescence activity of having a large surface area solid with periodic porous structure is revealed by the fact that an analogous amorphous material prepared with the same precursor does not exhibit any measurable electrochemiluminescence activity under the same conditions.

Functional Macromolecules from Single‐Walled Carbon Nanotubes: Synthesis and Photophysical Properties of Short Single‐Walled Carbon Nanotubes Functionalised with 9,10‐Diphenylanthracene

“…[48] DPA bearing styryl units has been previously reported in the literature and is obtained in high yields by palladium-catalysed Suzuki-Miyaura coupling of 9,10-dibromoanthracene and 4-styrylboronic acid. [49] Mercaptoethylamido-functionalised sSWNTs are in turn obtained by the formation of a peptide bond between the carboxylic groups present in the sSWNTs and mercaptoethanamine. As it is known that in SWNTs carboxylic acids are localised at the tips and defects of the nanotubes, [18,19] our functionalisation approach leaves unaltered the integrity of the graphene walls with respect to those of sSWNTs.…”

Organosilica Spheres Covalently Functionalized with Diphenylanthracene and Viologen Units

“…The characteristic vibrational fine structure of anthracene and its derivatives between 300 and 450 nm was clearly observed in the absorption spectrum of the DPA@SPH. [17] The diffuse reflectance UV/Vis spectrum of the VIO@SPH has an intense absorption band at 280 nm (not shown in Figure 5), overlapped with the bands of the phenyl groups, present also in PTMS@SPH, which corresponds to the aromatic p!p* transition of pyridinium rings, [20] together with a less intense, broader absorption around 410 nm. Based on the well known ability of viologen to form charge-transfer complexes with electron donor compounds, particularly with halides, [21][22] we attribute this absorption in the visible to the formation of a charge-transfer complex of viologen with iodide, which is the counter-anion of the positively charged viologen disilane precursor.…”

“…[18][19] The resulting 9,10-bis[p-styryl]anthracene was reacted with 3-mercaptopropyltrimethoxysilane using AIBN as radical initiator under inert atmosphere. [17] These conditions have been adequate to avoid decomposition of trimethoxysilyl group while ensuring a quantitative reaction yield. For the viologen precursor, trimethoxysilylpropyl groups were attached to the N atoms of the 4,4'-bipyridine by nucleophilic substitution.…”

“…To put into context the film obtained with spherical particles shown in Figure 10, it is worth commenting that previous studies on the electroluminescence of zeolite encapsulated guest molecules have shown that formation of uniform layers of irregularly shaped, micrometric zeolites is one of the major problems for developing zeolite-based electroluminescence devices. [17,[34][35][36] When instead of DPA@SPH coating of the ITO electrode is carried out with DPA@Silica lacking uniform particle distribution and spherical shaped particle, then the morphology of the film is considerably less uniform (see also Figure 10). …”

“…[15][16] The electroluminescent properties of diphenylanthracene have also been reported in literature. [17] Herein, we report the preparation of monodisperse organosilica spheres functionalized with two photoactive moieties, namely viologen (VIO) and diphenylanthracene (DPA). We will present the photophysical properties of these photoactive organosilica spheres.…”