Silsesquioxane‐based nanocomposite dendrimers with photo‐luminescent and charge transport properties

Abstract

The synthesis and characterization of octavinylsilsesquioxane (OVS)-based nanocomposite dendrimers with luminescent and charge transport properties are reported. The nanocomposite dendrimers were prepared in high yield using mild Heck chemistry of mono-haloaromatic compounds with the peripheral vinylsilane groups of OVS. Attachment of 2-naphthalene, 2-(9,9-dimethyl)fluorene, and 2-(4-phenyl)-5-(1-naphthyl)-1,3,4-oxadiazole resulted in materials with blue-violet emission (360-380 nm) and photo-luminescent quantum efficiencies (PLQEs) from 1 to 26%. Blue-green emission was observed for attachment of 1-pyrene, 9-anthracene, and N1-(4-phenyl)-N1,N4,N4-triphenylbenzene-1,4-diamine with PLQEs ranging from 23 to 50%. Despite the planar characteristics of the organic dendrons, the nanocomposite dendrimers are completely amorphous and have high glass transition temperatures (Tg) ranging from 115 to 186 degrees C with decomposition temperatures (Td) exceeding 450 degrees C. Matrix-assisted laser desorption ionization-time of flight shows that unlike traditional Heck chemistry, haloaromatic compounds are adding twice across the vinylsilane groups. Finally, organic light emitting diodes using the aromatic amine-based dendrimer as hole injection layers show 55% improvement in device efficiency over traditional materials (5.16 vs. 3.24 cd A(-1)) with brightness levels exceeding 40,000 cd m(-2).

Asymmetric aryl polyhedral oligomeric silsesquioxanes (ArPOSS) with enhanced solubility

“…To circumvent these limitations, several research groups have focused on the modification of aryl-functionalized POSS compounds. For example, Sellinger et al functionalized vinyl 8 Si 8 O 12 with aromatic photo-luminescent compounds via Heck coupling [18,19]. Laine et al reported the synthesis of (para-iodophenyl) 8 Si 8 O 12 as a platform for coupling additional organic moieties to POSS cages [20].…”

Triphenylamine‐Functionalized Silsesquioxane‐Based Hybrid Porous Polymers: Tunable Porosity and Luminescence for Multianalyte Detection

“…OVS has also been used to prepare hybrid porous polymers through various methods such as free radical polymerization, the Heck reaction, and the Friedel–Crafts reaction . The introduction of rigid and bulky cage units into luminescent molecules can inhibit aggregation and improve the fluorescence quantum efficiency . For example, Laine et al.…”

Aerobic Palladium(II)-Catalyzed Dehydrogenative Heck Reaction in the Synthesis of Pyrenyl Fluorophores. A Photophysical Study of β-Pyrenyl Acrylates in Solution and in the Solid State

“…8 It has been found that the conjugation of alkenyl groups with the pyrenyl moiety strongly influences the electronic structure and luminescent properties of such compounds. [12][13][14][15] In this paper we present a preliminary report on a simple, efficient, atom-and stepeconomical route to alkenylpyrenes having an ester group at the alkenyl group (pyrenyl acrylates) based on dehydrogenative alkenylation (dehydrogenative Heck reaction, i.e. [12][13][14][15] In this paper we present a preliminary report on a simple, efficient, atom-and stepeconomical route to alkenylpyrenes having an ester group at the alkenyl group (pyrenyl acrylates) based on dehydrogenative alkenylation (dehydrogenative Heck reaction, i.e.…”