An Ultra‐Long‐Lived Triplet Excited State in Water at Room Temperature: Insights on the Molecular Design of Tridecafullerenes

Abstract

Suitably engineered molecular systems exhibiting triplet excited states with very long lifetimes are important for high‐end applications in nonlinear optics, photocatalysis, or biomedicine. We report the finding of an ultra‐long‐lived triplet state with a mean lifetime of 93 ms in an aqueous phase at room temperature, measured for a globular tridecafullerene with a highly compact glycodendrimeric structure. A series of three tridecafullerenes bearing different glycodendrons and spacers to the C60 units have been synthesized and characterized. UV/Vis spectra and DLS experiments confirm their aggregation in water. Steady‐state and time‐resolved fluorescence experiments suggest a different degree of inner solvation of the multifullerenes depending on their molecular design. Efficient quenching of the triplet states by O2 but not by waterborne azide anions has been observed. Molecular modelling reveals dissimilar access of the aqueous phase to the internal structure of the tridecafullerenes, differently shielded by the glycodendrimeric shell.

Topological and Multivalent Effects in Glycofullerene Oligomers as EBOLA Virus Inhibitors

“…The synthesis of glycoconjugates 1 – 3 was carried out by following a click chemistry strategy, which required the preparation of a clickable glycofullerene containing ten mannose units and an azido group. The synthesis of this asymmetric A 10 B macromonomer started from hexakis-adduct 5 [ 26 ], as depicted in Scheme 1 . Glycofullerene 7 was obtained by CuAAC addition of 2-[2-(2-azidoethoxy)ethoxy]ethyl α-D-mannopyranoside ( 6 ) [ 27 ] to polyalkyne 5 in DMSO, using CuBr·S(Me) 2 as catalyst [ 14 , 28 ], after purification by treatment with Quadrasil MP resin to remove the copper catalyst and by size-exclusion chromatography using a Sephadex G25 gel filtration system (H 2 O:MeOH, 9:1).…”

“…Reagents and solvents were purchased as reagent grade and used without further purification. Compounds 5 , [ 26 ] 6 [ 27 ], and 12 [ 18 ] were prepared according to previously reported procedures. For column chromatography, silica gel 60 (230–400 mesh, 0.040–0.063 mm) was purchased from E. Merck and Sephadex G25 for gel filtration from GE Healthcare, Barcelona, Spain.…”

Multivalent glycosystems for human lectins

“…In the search for innovative 3D multivalent scaffolds, carbon nanoforms, such as fullerene C 60 , have been considered as an interesting biocompatible carbon platform for the multivalent presentation of carbohydrates. [125][126][127][128] In this context, glycofullerenes with a T h octahedral symmetry and globular structure have been used simulating the carbohydrate coating on the viral surface which can interfere with the virus infection process by blocking DC-SIGN. [129][130][131] This topic will be covered in detail in another review of this issue.…”

Carbon-based glyco-nanoplatforms: towards the next generation of glycan-based multivalent probes

“…In fact, the importance of the length of the linker of new tridecafullerenes had already been highlighted in other applications such as in the photophysical behavior of these kind of macromolecules in water. 163 Amphiphilic dendrofullerenes using fullerene C 60 functionalized with two and four trivalent mannose glycodendrons were also explored to study the antiviral impact of different sizes and geometry of glycofullerenes. 164 These glycodendrofullerenes with amphiphilic character in aqueous media selfassembled into spherical aggregates of micelle type as determined by scanning electron microscopy (SEM) and XRD and low angles X-ray scattering (SAXS) experiments.…”

“…In fact, the importance of the length of the linker of new tridecafullerenes had already been highlighted in other applications such as in the photophysical behavior of these kind of macromolecules in water. 163 …”