DMSO: An Efficient Catalyst for the Cyclopropanation of C60, C70, SWNTs, and Graphene through the Bingel Reaction

Click synthesis of dendronized malonates for the preparation of amphiphilic dendro[60]fullerenes

Fullerene C60 and its malonate derivatives, produced via the Bingel-Hirsch reaction, have displayed promising properties against various diseases. These molecules have great therapeutic potential, but their broad use has been limited due to poor aqueous solubility and toxicity caused by accumulation. In this study, we synthesized new malonates and malonamides attached to first- and second-generation polyester dendrons using click chemistry (CuAAC). These dendrons were then linked at C60 through the Bingel-Hirsch reaction, resulting in an amphiphilic system that retains the hydrophobic nature of C60. The dendronized malonate derivatives showed good reaction yields for the Bingel-Hirsch mono-adducts and were easier to work with than the corresponding malonamides. However, the malonamide derivatives, which were obtained through a multistep reaction sequence, showed moderate yields in the Bingel-Hirsch reaction. Surprisingly, removing acetonide protecting groups from dendritic architectures was more challenging than anticipated, likely due to product decomposition. Only the corresponding free malonate derivatives 25 and 26 were obtained, but in a low yield due to decomposition under the reaction conditions. Meanwhile, it was not possible to obtain the corresponding malonamide derivatives 27 and 28. Currently, efforts are being made to improve the production of the desired molecules and to design new synthesis routes that allow direct access to the desired poly-hydroxylated derivatives. These derivatives will be evaluated as multitarget ligands against Alzheimer's disease, through their use as inhibitors of amyloid β-peptide aggregation, acetylcholinesterase modulators, and antioxidants.

Two-Legged Molecular Walker and Curvature: Mechanochemical Ring Migration on Graphene

Attaining controllable molecular motion at the nanoscale can be beneficial for multiple reasons, spanning from optoelectronics to catalysis. Here we study the movement of a two-legged molecular walker by modeling the migration of a phenyl aziridine ring on curved graphene. We find that directional ring migration can be attained on graphene in the cases of both 1D (wrinkled/rippled) and 2D (bubble-shaped) curvature. Using a descriptor approach based on graphene's frontier orbital orientation, we can understand the changes in binding energy of the ring as it translates across different sites with variable curvature and the kinetic barriers associated with ring migration. Additionally, we show that the extent of covalent bonding between graphene and the molecule at different sites directly controls the binding energy gradient, propelling molecular migration. Importantly, one can envision such walkers as carriers of charge and disruptors of local bonding. This study enables a new way to tune the electronic structure of two-dimensional materials for a range of applications.

Ex situ synthesis of MOF@PET/cotton textile fibers as potential antibacterial materials

There is considerable scientific literature on MOF-based antibacterial textiles, especially with in situ methodologies for their synthesis. On the contrary, the ex situ synthesis of MOFs on fabrics has been little explored. Although, the latter may have more significant advantages when the expectation is to scale up the process industrially. The present study describes the synthesis of ex situ obtained MOF-199 and MOF-UiO-66-NH2 onto carboxylated polyester/cotton (PETco) textile fibers and their preliminary-qualitative analysis as potential antibacterial textiles. For this, free synthesized MOFs were anchored on a previously carboxylated PETco fiber, using conditions that seek the formation of coordination bonds between the carboxyl groups of the fiber and the metal in the MOF. After soxhlet purification with water and methanol for more than 48 h, analysis by FTIR-ATR and XRD shows the superposition of signals typical of the fiber and the MOF, resembling what was previously reported for cotton-MOF systems. XPS showed 4.47% Cu, with Cu–O-C interactions for MOF-199@PETco, and 12.06% Zr, with Zr-O-C interactions for MOF UiO-66-NH2@PETco. Results corroborated by the SEM micrographs, which show the expected morphology for MOF-199, and homogeneously distributed MOF UiO-66-NH2 crystals when they are anchored to the fiber.

Recent trends in covalent functionalization of 2D materials

Covalent functionalization of the surface is more crucial in 2D materials than in conventional bulk materials because of their atomic thinness, large surface-to-volume ratio, and uniform surface chemical potential. Because...

Methanofullerene Synthesis via Photogenerated Fullerene Radical Anion Intermediates

This work describes the synthesis of PCBM ([6,6]-phenyl-C₆₁-butyric acid methyl ester) derivatives and other methanofullerene derivatives via generation of fullerene radical anions under photoirradiation and controlled by photoswitching, without preparation, a strong reducing agent, or precise control of the reaction conditions.

Nucleophilic cyclopropanation of [60]fullerene by the addition-elimination mechanism

Information on the synthesis of monofunctionalized methanofullerenes C60 obtained by the addition-elimination mechanism is generalized. The main reagents for cyclopropanation, mechanisms and optimal conditions for the processes, and the prospects for practical application of the products are considered.

Reaction of the C60 radical anion with alkyl halides

A new reductive alkylation of C₆₀ with α-bromo-1,3-dicarbonyl compounds, benzyl halide, and 1,2-bis(dihalomethyl)benzene has been reported.

Synthesis and self-sensitized photo-oxidation of 2-fulleropyrrolines by palladium(ii)-catalyzed heteroannulation of [60]fullerene with benzoyl hydrazone esters

A Pd(OAc)₂-catalyzed N-heteroannulation reaction was exploited to synthesize N-unsubstituted 2-fulleropyrrolines and the photo-oxidation of 2-fulleropyrrolines was first investigated.

N-Alkylation and Aminohydroxylation of 2-Azidobenzenesulfonamide Gives a Pyrrolobenzothiadiazepine Precursor Whereas Attempted N-Alkylation of 2-Azidobenzamide Gives Benzotriazinones and Quinazolinones

N-Alkylation of 2-azidobenzenesulfonamide with 5-bromopent-1-ene gave an N-pentenyl sulfonamide, which underwent intramolecular aminohydroxylation to give an N-(2-azidoaryl)sulfonyl prolinol, a precursor for the synthesis of a pyrrolobenzothiadiazepine. The attempted N-alkylation of 2-azidobenzamide gave a separable mixture (∼1:1) of a benzotriazinone and a quinazolinone in a 72% combined yield. Other primary alkyl halides (3 examples) gave similar mixtures of benzotriazinones and quinazolinones. Benzylic, allylic, and secondary and tertiary alkyl halides (5 examples) gave only benzotriazinones in moderate yields. The results of mechanistic studies show the likely involvement of nitrene intermediates in the quinazolinone pathway and a second pathway involving a dimethylsulfoxide or dimethylsulfide-mediated conversion of 2-azidobenzamide into benzotriazinones.

Repurposing of oxazolone chemistry: gaining access to functionalized graphene nanosheets in a top-down approach from graphite

Solvent-free 1,3-dipolar cycloaddition reactions of graphite flakes and mesoionic oxazolones lead to the direct functionalization and delamination of graphite flakes into few layers of graphene nanosheets.

Solvent-free 1,3-dipolar cycloaddition (1,3-DC) reactions between graphite flakes and mesoionic oxazolones were carried out by heating the resulting solid mixture at mild temperatures (70–120 °C). The direct functionalization and delamination of graphite flakes into few layers of graphene nanosheets was confirmed by micro-Raman and X-ray photoelectron spectroscopies, scanning transmission electron microscopy and thermogravimetric analysis. The 1,3-DC reactions of mesoionic dipoles have been investigated with density functional theory to model graphene, exploring three different pathways: center, corner and edge. These theoretical calculations highlighted that the 1,3-DC reaction can proceed both through a concerted mechanism competing with a stepwise one involving a zwitterionic intermediate. The irreversible decarboxylation inherent in the last step justifies the high degree of functionalization experimentally observed, representing the driving force of the process.