A remarkable stability of a supramolecular radical comprising an azafullerene (C59N•) radical sterically protected by a [10]cycloparaphenylene ([10]CPP) nanoring, C59N•⊂[10]CPP, has recently been observed by various experimental probes. In order to investigate the host-guest interaction in these supramolecular complexes, we carried out electron paramagnetic resonance (EPR) measurements, theoretically supported by density functional theory (DFT) calculations. The continuous wave (CW) EPR spectrum shows the presence of two active spin components: C59N•⊂[10]CPP monomers that can in certain cases polymerize into oligomeric radicals. Two- and three-pulse electron spin echo envelope modulation (ESEEM) measurements allow for determination of experimental hyperfine coupling constants for 13C and 1H atoms and also show the strong coupling to the 14N atom adjacent to the radical C of the azafullerene. These experimental hyperfine coupling constants reasonably agree with those calculated for the DFT optimized supramolecular structures. The results are consistent with a small spin delocalization from the guest (C59N•) to the host ([10]CPP), thereby explaining weak but non-negligible interaction between them. Our study demonstrates that ESEEM experiments in alliance with DFT computations can offer valuable insights into the radical host-guest structures.

We present an efficient strategy for on-surface engineering of organic metal-free supramolecular complexes with long-term spin protection. By vacuum deposition of azafullerene (C59N•) monomers on a pre-deposited template layer of [10]cycloparaphenylene ([10]CPP) nanohoops on Au(111) surface we exploit the molecular shape matching between the C59N• and [10]CPP for the azafullerene encapsulation with nanohoops in a guest-host complexation geometry. C59N•⊂[10]CPP supramolecular complexes self-assemble into an extended two-dimensional hexagonal lattice yielding a high density network of stable spin-1/2 radicals. We find compelling evidence for electronic coupling between the guest C59N• and the host [10]CPP in supramolecular species. At the same time, [10]CPP effectively protects the radical state of encapsulated azafullerenes against dimerization and inhibits C59N• coupling to the Au substrate. Azafullerene encapsulation by nanohoops represents a viable realization of molecular spin protection while simultaneously demonstrating exceptional self-assembling properties by which large-scale 2D architectures of molecular spins can be realized.

We use molecular dynamics calculations to investigate the behavior of metal cations (Li, Na and Zn) within ionic liquids (ILs), specifically EMIM-TFSI, and their impact on key properties, particularly focusing on ion-ion correlations and their influence on diffusion and conductivity. The study explores the competition between metal cations and EMIM ions for binding to TFSI and analyzes ion pair dynamics, revealing that metal cation-TFSI pairs exhibit significantly longer lifetimes compared to TFSI-EMIM pairs. This competitive interaction and the increased stability of metal cation-TFSI pairs at higher concentrations leads to reduced ion exchange, resulting in decreased diffusion and conductivity. The observations underscore the importance of ion size and charge in determining their behavior regarding IL dynamics. Overall, this work provides valuable insights for designing ILs with customized properties, particularly in the context of optimizing conductivity and addressing energy storage challenges.

AlF3 and MgF2 are important catalysts for fluorination processes. In this study we characterise structures consisting of either AlF3, or MgF2 supported over AlF3, using Fourier transform infrared spectroscopy of surface absorbed CO. We interpret the results using atomic-scale density functional calculations, along with high-resolution electron microscopy and spectroscopy. By coupling theory to vibrational spectroscopy we are able to establish different stable facets in the host species, identifying both surface physisorbed CO binding to pristine facets, and chemisorbed CO binding to fluorine anion vacancy sites. In the case of MgF2 supported over AlF3 surfaces we suggest that a 50 : 50 mixed Mg-AlFx monolayer surface phase can form. Excess MgF2 deposition subsequently results in the formation of MgF2 nanoparticles on the surface. Mixed composition surface phases may play a critical role in Al/MgFx fluorine catalysis.

We successfully functionalized MoS2 and WS2 with Zn-porphyrin through 1,2-dithiolane addition. This createsmixed 0-2 dimensional materials since porphyrins are discreteon the basal plane of TMDs. This localization results in a new emissionband with a 3.5 ns lifetime at 77.5 K with an excitation power of17 W/cm(2) in the near-infrared (NIR) region (1.40-1.51eV), which originates from charge-separated states between ZnP andWS(2). The optical response of excitonic species, includingtrion, biexcitons, and excitons, is substantially enhanced at theporphyrin absorption region, supporting electron transfer betweenZnP and WS2. Sensing time-response improves after functionalization,suggesting that electrons injected from ZnP to TMDs contribute tofilling trap states. Incorporating ZnP also enhances the stabilityof WS2 and MoS2 against atmospheric photodegradation.Theoretical modeling supports these findings, suggesting an intimaterelationship between orbitals in the ground and excited states ofporphyrin and TMDs.

We investigate the contribution of pseudocapacitance to the overall capacitance of MnO2 electrodes in pure and alkaline-doped ionic liquids via two spectroscopic methods: step potential electrochemical spectroscopy (SPECS) and in situ Raman spectroscopy. For both characterization methods, thin-film electrodes of birnessite-like amorphous MnO2 were cycled in Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, pure or doped with lithium or sodium. SPECS allows determination of the influence of the electrolyte composition on the electrochemical behavior of the MnO2 electrodes. Pseudocapacitive charge storage can account for over half of the total capacitance with alkaline-doped ionic liquids. In situ Raman spectroscopy provided insight into the reversible ion intercalation in the MnO2 structure, which appears to be controlled by EMIm+ cations. These findings are supported by density functional theory (DFT) calculations, which further help unveil the charge storage mechanism in birnessite-like amorphous MnO2 thin films operated in pure and alkaline-doped ionic liquids.

We investigate the effect of introducing C60 to (C59N)2 and the molecular ring, [10]cycloparaphenylene ([10]CPP), using electron paramagnetic resonance (EPR) measurements supported by density functional theory (DFT) calculations. Incorporating C60 into the system results in the formation of novel stable [10]CPP D C59N-C60 center dot C [10]CPP encapsulated heterodimer radicals whose spin is localized on C60 and manifests in EPR measurements as a signal at g = 2.0022 without any discernable hyperfine structure. This signal has an exceptionally long spin coherence lifetime of 440 mu s at room temperature, far longer than any of the radical fullerene species reported in the literature and over twice that of the C59N center dot C [10]CPP radical. The radicals are long-lived, with EPR signal still strong over a year after thermal activation. The [10]CPP D C59N-C60 center dot C [10]CPP oligomer is more stable than C59N center dot C [10]CPP radicals and becomes the predominant species at room temperature after annealing. Its formation is thermally activated with an experimental activation energy of only 0.189 eV, as compared to 0.485 eV for the pure azafullerene-[10]CPP case. The [10]CPP D C59N-C60 center dot C [10]CPP radicals discovered here could be used to bridge C59N center dot C [10]-CPPs acting as qubits, providing effective coupling between them.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

We deposit azafullerene C59N• radicals in a vacuum on the Au(111) surface for layer thicknesses between 0.35 and 2.1 monolayers (ML). The layers are characterized using X-ray photoemission (XPS) and X-ray absorption fine structure (NEXAFS) spectroscopy, low-temperature scanning tunneling microscopy (STM), and by density functional calculations (DFT). The singly unoccupied C59N orbital (SUMO) has been identified in the N 1s NEXAFS/XPS spectra of C59N layers as a spectroscopic fingerprint of the molecular radical state. At low molecular coverages (up to 1 ML), films of monomeric C59N are stabilized with the nonbonded carbon orbital neighboring the nitrogen oriented toward the Au substrate, whereas in-plane intermolecular coupling into diamagnetic (C59N)2 dimers takes over toward the completion of the second layer. By following the C59N• SUMO peak intensity with increasing molecular coverage, we identify an intermediate high-spin-density phase between 1 and 2 ML, where uncoupled C59N• monomers in the second layer with pronounced radical character are formed. We argue that the C59N• radical stabilization of this supramonolayer phase of monomers is achieved by suppressed coupling to the substrate. This results from molecular isolation on top of the passivating azafullerene contact layer, which can be explored for molecular radical state stabilization and positioning on solid substrates.

Explosive percolation is an experimentally-elusive phenomenon where network connectivity coincides with onset of an additional modification of the system; materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network. Nanocomposites present a structurally- and chemically-varied playground to realise explosive percolation in practically-applicable systems but this is yet to be exploited by design. Herein, we demonstrate composites of graphene oxide and synthetic polymer latex which form segregated networks, leading to low percolation threshold and localisation of conductive pathways. In situ reduction of the graphene oxide at temperatures of <150 °C drives chemical modification of the polymer matrix to produce species with phenolic groups, which are known crosslinking agents. This leads to conductivities exceeding those of dense-packed networks of reduced graphene oxide, illustrating the potential of explosive percolation by design to realise low-loading composites with dramatically-enhanced electrical transport properties.

Using laser-induced vaporisation to evaporate and ionise a source of curved polyaromatic hydrocarbons (carbon nanobelts), we show collision impacts between species cause mass loss and the resultant ions are catalogued via mass-spectrometry. These data are interpreted via a series of “in-silico”-simulated systematic hydrogen-loss studies using density functional theory modelling, sequentially removing hydrogen atoms using thermodynamic stability as a selection for subsequent dehydrogenation. Initial hydrogen loss results in the formation of carbyne chains and pentagon-chains while the nanobelt rings are maintained, giving rise to new circular strained dehydrobenzoannulene species. The chains subsequently break, releasing CH and C2. Alternative routes towards the formation of closed-cages (fullerenes) are identified but shown to be less stable than chain formation, and are not observed experimentally. The results provide important information on collision degradation routes of curved molecular carbon species, and notably serve as a useful guide to high-energy impact conditions observed in some astrochemical environments.

We explore the importance of curvature in carbonaceaous species transformation and stability, using laser-induced vaporisation to evaporate and ionise a source of curved polyaromatic hydrocarbons: carbon nanobelts. Collision impacts between species cause mass loss and the resultant ions are catalogued via mass-spectrometry. To interpret the mass spectra, we perform a series of “in-silico” simulated systematic hydrogen-loss studies using density functional theory (DFT) modelling, sequentially removing hydrogen atoms using thermodynamic stability as a selection for subsequent dehydrogenation. In an initial sequence of H2 removal, the rings are maintained through stable carbyne chain and pentagon-chain formation, giving rise to circular strained dehydrobenzoannulene species. The chains subsequently break, releasing CH and C2. While theoretical closed-cage routes are identified, they are not observed experimentally. The results can serve as a useful guide to high-energy impact conditions observed in some astrochemical environments.

Dislocations are a central concept in materials science, which dictate the plastic deformation and damage evolution in materials. Layered materials such as graphite admit two general types of interlayer dislocations: basal and prismatic dislocations, of which prismatic dislocations have been relatively less studied. Using density functional theory (DFT) calculations, we have examined different prismatic core structures in graphite and evaluated their structure, energetics and mobility. We find close energetic interplay between bonded and “free-standing” core structures in both zigzag and armchair directions, with a reconstructed stable zigzag core identified. We explore grain boundaries and prismatic dislocation pile-up, identifying metastable structures which may be important in energy storage. The role of interlayer stacking in core structure, dislocation glide and climb is also considered in-depth. Our calculations suggest that the prismatic dislocation core is stable up to high temperatures of approximately 1500K in bulk graphite. Above this temperature, the breaking of bonds in the dislocation core can facilitate climb, grain-boundary motion, and the annealing of damage through prismatic dislocation glide.

We report the intercalation of iodine chains in highly crystalline arc-discharge multiwalled carbon nanotubes (MWCNTs), not in the central cavity but instead between the concentric graphene shells. High-resolution transmission electron microscopy demonstrated that the intercalation was asymmetric with respect to the longitudinal axis of the nanotubes. This filling is explained through the existence of asymmetric intershell channels which formed as the tubes shrank upon cooling after growth. Shrinkage occurred because the geometrically constrained equilibrium intershell spacing was higher at growth than room temperature, due to the highly anisotropic coefficient of thermal expansion of graphite (or graphene stacks). Computational modelling supported the formation of such cavities and explained why they all formed on the same side of the tubes. The graphene shells were forced to bend outward, thereby opening aligned intergraphene nanocavities, and subsequently allowing the intercalation with iodine once the tube ends were opened by oxidative treatment. These observations are specific to catalyst-free processes because catalytic processes use too low temperatures, but they are generally applicable in geometrically closed carbon structures grown at high temperatures and so should be present in all arc-grown MWCNTs. They are likely to explain multiple observations in the literature of asymmetric interlayer spacings in multiple-shell graphenic carbon structures.

We identify the "missing" 1D-phosphorus allotrope, red phosphorus chains, formed in the interior of tip-opened single-walled carbon nanotubes (SWCNTs). Via a comprehensive experimental and theoretical study we show that in intermediate diameter cavities (1.6-2.9 nm), phosphorus vapor condenses into linear P8]P2 chains and fibrous red-phosphorus type cross-linked double-chains. Thermogravimetric and X-ray photoelectron spectroscopy analysis estimates ∼7 atom % of elemental phosphorus in the sample, while high-resolution energy dispersive X-ray spectroscopy mapping reveals that phosphorus fills the SWCNTs. High-resolution transmission electron microscopy (HRTEM) shows long chains inside the nanotubes with varying arrangement and packing density. A detailed match is obtained between density functional theory (DFT) simulations, HRTEM, and low-frequency Raman spectroscopy. Notably, a signature spectroscopic signal for phosphorus chain cross-linking is identified. When coupled with reinterpretation of literature data and wide-ranging DFT calculations, these results reveal a comprehensive picture of the diameter dependence of confined 1D-phosphorus allotropes.

Folded regions are commonly encountered in a number of hexagonal boron nitride (h-BN) based bulk and nanostructured materials. Two types of structural modifications occur in folded h-BN layers: local curvature at the folded edges and interlayer shear of the layers which changes the stacking of the overlapping flat regions. In this work we discuss, via density functional theory simulations, the impact of these structural modifications on the ground state electronic structure of the pristine monolayer. We show that, depending on the fold orientation, the overlapping region might present different stacking configurations with subsequent variations of the fundamental band gap; further gap changes occur at the folded regions. The overall electronic structure of a BN folded monolayer can finally be described as a type-II junction between two wide gap semiconductors located at the curved and flat overlapping zones.

Cutting and folding 2D systems is one of the explored paths to tune physical and chemical properties in one-atom-thick matter. Contrary to graphene, boron nitride (BN) nanoribbons are difficult to obtain, and folded BN nanoribbon structures have not been reported yet. Here, we show that pressure application in multiwalled boron nitride nanotubes leads to different types of tube internal organizations including BN nanoribbon formation and folds. The new structures are associated with the breaking of a number of the internal tubes, leading to either nonorganized structures in the form of internal tube alveoli or an organized stacking of folded h-BN nanoribbons. Irreversible changes in the morphology of multiwalled BN nanotubes (MWBNNTs) take place from similar to 7 GPa, and morphologically modified tubes could be observed up to pressures of at least 49 GPa. The experimental probes utilized included high-resolution transmission microscopy, electron tomography, and Raman spectroscopy. Atomistic modeling shows the formation of pinch structures along the tubes that favor pressure-induced bond-breaking and hybridization changes and confirm the folded structure. Both experiments and modeling show that tube polygonization is a prominent characteristic of MWBNNTs even at ambient pressure. Overall, the pressure evolution of MWBNNTs strongly differs from their carbon analogues. The high mechanical stability of BN tube geometry is of interest for composite-based structural materials. On the other side, the availability of h-BN nanoribbons and folded structures opens new prospects to produce physically modified BN properties.