Covalent organic functionalization of graphene nanosheets and reduced graphene oxide<i>via</i>1,3-dipolar cycloaddition of azomethine ylide

Basta, Luca; Moscardini, Aldo; Fabbri, Filippo; Bellucci, Luca; Tozzini, Valentina; Rubini, S.; Griesi, Andrea; Gemmi, Mauro; Heun, S.; Veronesi, S.

doi:10.1039/d1na00335f

Cited by 15 publications

(28 citation statements)

References 124 publications

(138 reference statements)

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“…26 After that, the ylide undergoes a 1,3-cycloaddition reaction with the C C double bonds present on the graphene structure and results in HRFGs, wherein the extended hydroxyl branches are connected via an N-containing 5-membered (N-5) ring (Scheme S1, SI). 22,24 Based on the mechanistic path involved, systematically experiments were performed to understand the extent of reaction completion at fixed time intervals of 24 h. Related materials have been named HRFG-24, HRFG-48, HRFG-72, and HRFG-96, respectively, based on the duration of the reaction time in hours. The synthesized samples were first characterized by FTIR, and the spectra for OFG and HRFGs are shown in Figure 1b, wherein the peaks at ∼1246 and ∼1582 cm −1 were related to the C−O and CC bond stretching frequency, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…17,23 Basta et al further investigated the 1,3-cycloaddition reaction with detailed solvent effects and functionalization efficiency for a similar reaction with graphene or rGO and further supported the conclusions with computational investigations. 24 However, the study lacked a detailed time-dependent synthesis study and establishment for such materials for various applications.…”

Section: ■ Introductionmentioning

confidence: 99%

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Covalently Functionalized Hydroxyl-Rich Few-Layer Graphene for Solid-State Proton Conduction and Supercapacitor Applications

Mehra

Paul

2022

J. Phys. Chem. C

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Covalently functionalized hydroxyl-rich few-layer graphenes (HRFGs) have been synthesized from oxygenfunctionalized few-layer graphene (OFG) via 1,3-cycloaddition reaction of azomethine ylide as an intermediate, and the best nanomaterial was obtained after 96 h of reaction (HRFG-96). HRFG-96 provided a superlative proton conductivity of 1.0 × 10 −3 S cm −1 at room temperature and a low relative humidity of 40%. The material also displayed a weak humidity dependency for proton conduction. A remarkable proton conductivity of 3.94 × 10 −2 S cm −1 was obtained at 95 °C, and 95% relative humidity along with exceptional thermal and long-term stability for seven days. This outstanding performance was attributed to a stable hydration layer formation through extensive hydrogen bonding between the excess hydroxyl groups and water molecules, which provided high proton conduction even at low-humidity conditions. Moreover, the shorter crystallite size of HRFG-96 led to substantial enhancement of grain boundaries, which consequently increased the space charge as well. As a supercapacitor electrode material, HRFG-96 provided specific capacitances of 389 F g −1 at 1 mV s −1 and 320 F g −1 at a current density of 1 A g −1 in a three-electrode configuration. The nearly 53% of specific capacitance was due to excess hydroxy functionalization, which resulted in pseudocapacitance because of proton-coupled electron-transfer reactions. The material revealed 121% cyclic stability after 25,000 cycles due to the enhanced wettability during cycling that lowered the charge transfer resistance at the electrode/electrolyte interface and improved site-to-site charge transport.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Covalently Functionalized Hydroxyl-Rich Few-Layer Graphene for Solid-State Proton Conduction and Supercapacitor Applications

Mehra

Paul

2022

J. Phys. Chem. C

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“…The decrease of I(D)/I(G) can be explained considering that the molecules of azomethine ylide are grafting onto graphene's most favorable bonding sites in the patterned area, which are close to the defects, possibly leading to a local structural relaxation and a decrease in the Raman intensity of the defects themselves, as already seen in previous works. 26 A further sign of the functionalization is the rise of new bands in the Raman shift region 1050 -1750 cm -1 , which can be assigned with the aid of the computed PS (see Figure 5(b)).…”

Section: Patterned Graphene Flakesmentioning

confidence: 97%

“…This corresponds to the peak centered at 1705 cm -1 in the experimental Raman spectrum, as also seen in literature. 26,57 Another functional group of the azomethine ylide is the methyl group (CH 3 ), which possesses characteristic vibrational modes around 1110 cm -1 (as shown in the PS). This could correspond to the new band revealed in the Raman Figure 6.…”

Section: Patterned Graphene Flakesmentioning

confidence: 99%

“…22 It is known that defects can profoundly influence the chemical properties of graphene, 23 as its mechanical, thermal, and electronic properties. 24 For example, defective graphene has shown increased chemical reactivity towards both diazonium salt-promoted radical addition reaction 25 and 1,3-dipolar cycloaddition reaction, 26 which are commonly used approaches for the covalent organic functionalization of graphene-based materials. 27 While these approaches exploited already existing defects in graphene, like intrinsic boundaries and edges, a precise control on the spatial distribu-tion of the defects would be more valuable in order to obtain a position-controlled surface functionalization.…”

Section: Introductionmentioning

confidence: 99%

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Deterministic Covalent Organic Functionalization of Monolayer Graphene with 1,3-Dipolar Cycloaddition Via High Resolution Surface Engineering

Basta¹,

Bianco²,

Moscardini³

et al. 2022

Preprint

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Spatially-resolved organic functionalization of monolayer graphene is successfully achieved by combining lowenergy electron beam irradiation with 1,3-dipolar cycloaddition of azomethine ylide. Indeed, the modification of the graphene honeycomb lattice obtained via electron beam irradiation yields to a local increase of the graphene chemical reactivity. As a consequence, thanks to the high-spatially resolved generation of structural defects (∼ 100 nm), chemical reactivity patterning has been designed over the graphene surface in a well-controlled way. Atomic force microscopy and Raman spectroscopy allow to investigate the two-dimensional spatial distribution of the structural defects and the new features that arise from the 1,3-dipolar cycloaddition, confirming the spatial selectivity of the graphene functionalization achieved via defect engineering. The Raman signature of the functionalized graphene is investigated both experimentally and via ab initio molecular dynamics simulations, computing the power spectrum. Furthermore, the organic functionalization is shown to be reversible thanks to the desorption of the azomethine ylide induced by focused laser irradiation. The selective and reversible functionalization of high quality graphene using 1,3-dipolar cycloaddition is a significant step towards the controlled synthesis of graphene-based complex structures and devices at the nanoscale.

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Spin‐Injection in Graphene: An EPR and Raman Study

Fragkogiannis

Belles

Gournis

et al. 2023

Chemistry A European J

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In this article, the enrichment of graphene and graphene oxide with free radicals through their functionalization with tyrosine is studied. In contrast with what is commonly observed in the functionalization of graphene with organic species the addition of tyrosine radicals on to the graphene substrate led to a remarkable increase of the aromatic character as indicated by the spectroscopic data. Similar behavior was observed for the functionalization of graphene oxide. In addition, a brief analysis of the tyrosine functionalized graphene with EPR spectroscopy showed a remarkable enhancement of the spin density that could be useful in spintronics.

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Covalent organic functionalization of graphene nanosheets and reduced graphene oxidevia1,3-dipolar cycloaddition of azomethine ylide

Abstract: Organic functionalization of graphene is successfully performed via 1,3-dipolar cycloaddition of azomethine ylide in the liquid phase. The comparison between 1-methyl-2-pyrrolidinone and N,N-dimethylformamide as dispersant solvents, and between sonication and...

Cited by 15 publications

References 124 publications

Covalently Functionalized Hydroxyl-Rich Few-Layer Graphene for Solid-State Proton Conduction and Supercapacitor Applications

Covalently Functionalized Hydroxyl-Rich Few-Layer Graphene for Solid-State Proton Conduction and Supercapacitor Applications

Deterministic Covalent Organic Functionalization of Monolayer Graphene with 1,3-Dipolar Cycloaddition Via High Resolution Surface Engineering

Spin‐Injection in Graphene: An EPR and Raman Study

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