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The effects of the sequence of technology steps of electrical contact formation between carbyne layers and metal electrodes (gold, platinum) on contact parameters were explored. Enhancements in contact parameters were achieved through thermal annealing of the samples. Contact parameters were measured by transmission line method (TLM) and impedance spectroscopy after annealing at atmospheric conditions. Lowering of contact resistivity and sheet resistance of the carbyne layer after annealing was observed for temperatures up to 150∘C for palladium contacts and up to 100∘C for gold contacts. It was found that exceeding these temperatures is not recommended, as higher annealing temperatures led to a reduction in the sheet resistance of the carbyne layer. Based on these findings, it can be concluded that the electrical losses at metal contacts of carbyne-based devices, with Au or Pd metallization, can be reduced through annealing. This is particularly critical in carbyne-based gas sensors, where decreasing contact resistance enhances sensitivity. [ABSTRACT FROM AUTHOR]

Introduction: Traps at the interface between carbyne and palladium nanocoatings, produced at different growth conditions, are explored by currentvoltage characteristics, scanning electron microscopy and thermal stimulation of charges for evaluation of their nature. It was found that the Pd films can form an Ohmic contact with the carbyne at certain deposition conditions and such deviated from the Ohmic behavior according to the RF sputtering voltage. This growth parameter was found to affect the interfacial traps formation on the carbyne surface, which is important feature for the charge trapping and releasing properties for hydrogen isotopes in the context of the energy release applications. Methods, Results and Discussion: The sputtering voltages of 0.5 kV and 0.7 kV were found unsuitable for controlled trap formation. Based on the currentvoltage and thermally stimulated current (TSC) measurements, a sputtering voltage of 0.9 kV appeared to be more favorable compared to 0.5 kV and 0.7 kV. At 0.9 kV thermal activation of charge carriers are enabled at lower thermal energies, showing a distinct change in TSC behavior correlated to trap activation. [ABSTRACT FROM AUTHOR]

Introduction: Traps at the interface between carbyne and palladium nanocoatings, produced at different growth conditions, are explored by current-voltage characteristics, scanning electron microscopy and thermal stimulation of charges for evaluation of their nature. It was found that the Pd films can form an Ohmic contact with the carbyne at certain deposition conditions and such deviated from the Ohmic behavior according to the RF sputtering voltage. This growth parameter was found to affect the interfacial traps formation on the carbyne surface, which is important feature for the charge trapping and releasing properties for hydrogen isotopes in the context of the energy release applications.Methods, Results and Discussion: The sputtering voltages of 0.5 kV and 0.7 kV were found unsuitable for controlled trap formation. Based on the currentvoltage and thermally stimulated current (TSC) measurements, a sputtering voltage of 0.9 kV appeared to be more favorable compared to 0.5 kV and 0.7 kV. At 0.9 kV thermal activation of charge carriers are enabled at lower thermal energies, showing a distinct change in TSC behavior correlated to trap activation.

Solution-processed, large-area, and flexible electronics largely relies on the excellent electronic properties of sp2 -hybridized carbon molecules, either in the form of π-conjugated small molecules and polymers or graphene and carbon nanotubes. Carbon with sp-hybridization, the foundation of the elusive allotrope carbyne, offers vast opportunities for functionalized molecules in the form of linear carbon atomic wires (CAWs), with intriguing and even superior predicted electronic properties. While CAWs represent a vibrant field of research, to date, they have only been applied sparingly to molecular devices. The recent observation of the field-effect in microcrystalline cumulenes suggests their potential applications in solution-processed thin-film transistors but concerns surrounding the stability and electronic performance have precluded developments in this direction. In the present study, ideal field-effect characteristics are demonstrated for solution-processed thin films of tetraphenyl[3]cumulene, the shortest semiconducting CAW. Films are deposited through a scalable, large-area, meniscus-coating technique, providing transistors with hole mobilities in excess of 0.1 cm2  V-1  s-1 , as well as promising operational stability under dark conditions. These results offer a solid foundation for the exploitation of a vast class of molecular semiconductors for organic electronics based on sp-hybridized carbon systems and create a previously unexplored paradigm.

A convenient synthesis of [HB(HImMe)3](PF6)2 (ImMe = N-methylimidazolyl) is decribed. This salt serves in situ as a precursor to the tris(imidazolylidenyl)borate Li[HB(ImMe)3] pro-ligand upon deprotonation with nBuLi. Reaction with [W(≡CC6H4Me-4)(CO)2(pic)2(Br)] (pic = 4-picoline) affords the carbyne complex [W(≡CC6H4Me-4)(CO)2{HB(ImMe)3}]. Interrogation of experimental and computational data for this compound allow a ranking of familiar tripodal and facially coordinating ligands according to steric (percentage buried volume) and electronic (νCO) properties. The reaction of [W(≡CC6H4Me-4)(CO)2{HB(ImMe)3}] with [AuCl(SMe2)] affords the heterobimetallic semi-bridging carbyne complex [WAu(μ-CC6H4Me-4)(CO)2(Cl){HB(ImMe)3}]. [ABSTRACT FROM AUTHOR]

It is exhibited that failure of carbyne-graphene nanoelements and similar low-dimensional nanostructures at thermo-mechanical loading is stochastic by its nature. Lifetime of such low-dimensional nanostructures is governed by waiting time of the fluctuation-induced contact bonds breaking. It was ascertained that the lifetime distribution function is described by an exponential law, the parameter of which is the value of the probability of contact bond breaking during the period of one atomic vibration. A significant lifetime scatter is a characteristic feature of failure of this type of nanoelements under a constant loading value. This means that when using such nanoelements in practice, it is necessary to focus not on the average lifetime, but on its lower limit with a pre-specified value of failure probability 1% ... 5%. [ABSTRACT FROM AUTHOR]

Metallization for contacts in organic electronic nanodevices is of great importance for their performance. A lot of effects can appear at the contact/organic interface and modify the contact parameters, such as contact resistance, adhesive strength, and bonding ability. For novel materials, it is important to study the interactions with metal atoms to develop a suitable technology for contacts, fulfilling to the greatest extent the above-mentioned parameters. A novel material is carbyne, which is still under intensive research because of its great potential in electronics, especially for sensing applications. However, the most appropriate metallization strategy for carbyne-based devices is still unknown, so the interactions between carbyne and metal films should be studied to more precisely direct the development of the metallization technology, and to form contacts that are not limiting factors for device performance. [ABSTRACT FROM AUTHOR]

Pulsed Laser Deposition (PLD) is a highly flexible experimental methodology for the growth of thin films of a broad variety of materials, based on the generation of laser-induced plasmas (LIP) with material ablated from a solid target and on the transfer of the ablated material to a substrate. This review is focused on carbon-based materials—specifically, diamond-like carbon (DLC), graphene and carbyne—and will both discuss the influence of the most critical experimental parameters on the obtained materials and present the experimental developments proposed in the recent literature to tailor the properties of the deposited films and optimize the standard PLD technique for production of various carbon-based materials. [ABSTRACT FROM AUTHOR]

The approach is offered and the analytical dependences are obtained which enable to predict with sufficient accuracy the lifetime of carbyne–graphene and similar low-dimensional nanostructures under the simultaneous action of temperature and force field. Ideas on atomistic of the force field influence on the fluctuation-induced atomic bond break is developed. Existence of two components of above effect is ascertained, namely (i) decrease in the energy barrier under the force action, and (ii) reduction of the energy cost for the bond break due to release of the accumulated energy of elastic deformations. On the example of carbyne–graphene nanoelement, it is shown that the effect of force field can cause a drop of lifetime by tens of orders of magnitude. This is a manifestation of the synergy effect of temperature and force field on the stability and lifetime of nanostructures. The obtained dependences are a convenient tool for predicting the lifetime of low-dimensional nanostructures, in particular, of straintronics elements. On the whole, the approach proposed may be considered as a generalization of Arrhenius' theory of reactions in the case of force field action. [ABSTRACT FROM AUTHOR]

Exploration of organometallic metallacycles has led to the development of various polycyclic compounds with fascinating structures, which could be used as functional materials. In this work, a new rhenanaphthalene isomer was isolated from the reaction of ReH5(PMe2Ph)3 with o‐ethynylphenyl alkyne in the presence of excess HCl. Its structure was then identified using the single‐crystal X‐ray diffraction and NMR spectroscopy. DFT studies suggest that its formation involves two protonation reactions and two migration reactions. This new rhenanaphthalene isomer enriches the family of metallacycles. [ABSTRACT FROM AUTHOR]

Transistors made up of carbon nanotube CNT have demonstrated excellent current–voltage characteristics which outperform some high-grade silicon-based transistors. A continuously tunable energy barrier across semiconductor interfaces is desired to make the CNT-based transistors more robust. Despite that the direct band gap of the carbyne inside a CNT can be widely tuned by strain, the size of the carbyne cannot be controlled easily. The production of a monoatomic chain with more than 6000 carbon atoms is an enormous technological challenge. To predict the optimal chain length of a carbyne in different molecular environments, we have developed a Monte Carlo model in which a finite-length carbyne with a size of 4000–15,000 atoms is encapsulated by a CNT at finite temperatures. Our simulation shows that the stability of the carbyne@nanotube is strongly influenced by the nature and porosity of the CNT, the external pressure, the temperature, and the chain length. We have observed an initiation of the chain-breaking process in a compressed carbyne@nanotube. Our work provides much-needed input for optimizing the carbyne length to produce carbon chains much longer than 6000 atoms at ~300 K. Design rules are proposed for synthesizing ~1% strained carbyne@(6,5)CNT as a component in CNT-based transistors to tune the energy barriers continuously. [ABSTRACT FROM AUTHOR]

Au-pseudocarbynes are a new class of materials produced through non-covalent interactions between finite one dimensional sp -hybridized carbon chains and sub-nanometer metal clusters. These exciting and innovative materials are expected to approach the unprecedented theoretical strength, elastic modulus, and stiffness of carbyne, which has defied isolation and characterization for over a century. The current approach for synthesizing Au-pseudocarbynes relies on the laser ablation of a liquid/metal interface, and therefore limits its production to small yields through laser ablation. In this study, we synthesized Au-pseudocarbynes by a self-assembly of previously prepared gold clusters and polyynes in solution, which yields similar results under spectroscopic analysis and through x-ray diffraction to the products synthesized via laser ablation. Therefore, we obtain new insights toward their formation mechanism by showing that the extreme temperatures and pressures provided by laser ablation are not necessary for assembling gold particles with polyynes. This self-assembly approach also provides a new way to develop Au-pseudocarbynes for applications by enabling large-scale synthesis. [Display omitted] [ABSTRACT FROM AUTHOR]

Atomic mechanisms of the fluctuation-induced breaking of contact bonds in carbyne–graphene nanoelements under the force-field conditions are considered. Existence of two components of the force-field effect on the durability of carbyne–graphene nanoelements and similar two-dimensional nanostructures is ascertained, namely, (i) a decrease in the energy-barrier height under the force action and (ii) a decrease in expenditure of energy for breaking the bond due to the release of elastic-deformations’ energy accumulated within the nanoelement. As shown using the example of a carbyne– graphene nanoelement, the impact of the force field can cause a drop in durability by tens of orders of magnitude. This is a manifestation of the synergy of the temperature and force-field effects on the stability and durability of nanostructures. Approximate analytical dependences are derived, which enable predicting the durability of such two-dimensional nanostructures, in particular, as straintronics elements, with sufficient accuracy. From a theoretical point of view, the proposed approach may be considered as a generalization of the Arrhenius theory of reactions to the case of forcefield action. [ABSTRACT FROM AUTHOR]

A convenient synthesis of [HB(HImMe)3](PF6)2 (ImMe = N-methylimidazolyl) is decribed. This salt serves in situ as a precursor to the tris(imidazolylidenyl)borate Li[HB(ImMe)3] pro-ligand upon deprotonation with nBuLi. Reaction with [W(≡CC6H4Me-4)(CO)2(pic)2(Br)] (pic = 4-picoline) affords the carbyne complex [W(≡CC6H4Me-4)(CO)2{HB(ImMe)3}]. Interrogation of experimental and computational data for this compound allow a ranking of familiar tripodal and facially coordinating ligands according to steric (percentage buried volume) and electronic (νCO) properties. The reaction of [W(≡CC6H4Me-4)(CO)2{HB(ImMe)3}] with [AuCl(SMe2)] affords the heterobimetallic semi-bridging carbyne complex [WAu(μ-CC6H4Me-4)(CO)2(Cl){HB(ImMe)3}].

In this Comment, the content of the book by B.I. Kharisov, O.V. Kharissova, Carbon Allotropes: Metal-Complex Chemistry, Properties and Applications, published in 2019 by Springer Nature Publishing, has been characterized in detail. A great amount of information presented in this book is devoted to numerous varieties (allotropic modifications) of elemental carbon, each of which currently has not only purely academic, but also significant practical interest. This book is important for researchers working in the field of inorganic chemistry of carbon, as well as researchers in the field of chemistry of coordination compounds, which has traditionally been classified as inorganic chemistry since its inception. [ABSTRACT FROM AUTHOR]

There has been a lot of study and advancement in the area of carbon allotropes in the last several decades, driven by the exceptional and diverse physical and chemical characteristics of carbon nanomaterials. For example, nanostructured forms such as carbon nanotubes, graphene, and carbon quantum dots have the potential to revolutionize various industries [1-3]. The global scientific community continues to research in the field of creating new materials, particularly low-dimensional carbon allotropes such as carbon nanotubes (CNTs) and carbyne. Carbyne is a one-dimensional carbon allotrope with a large surface area, chemical reactivity, and gas molecule adsorption potential that makes it extremely sensitive to gases and electronic nose (E-nose) applications due to its linear sp-hybridized atomic chain structure. The primary objective of this work is to increase the sensitivity, selectivity, and overall efficiency of E-nose systems using a synergistic combination of carbyne-based sensing components with cutting-edge machine learning techniques. The exceptional electronic properties of carbyne, such as its high electron mobility and adjustable bandgap, enable rapid and specific adsorption of various gas molecules. Additionally, its significant surface area-to-volume ratio enhances the detection of trace concentrations. Our suggested advanced hybrid system utilises support vector machines (SVMs) and convolutional neural networks (CNNs) as sophisticated machine learning approaches to analyse data provided by carbyne sensors. These algorithms enhance the precision and durability of gas detection by effectively recognising intricate patterns and correlations in the sensor data. Empirical evidence suggests that E-nose systems based on carbyne have superior performance in terms of reaction time, sensitivity, and specificity compared to conventional materials. This research emphasises the revolutionary potential of carbyne in the advancement of next-generation gas sensing systems, which has significant implications for applications in environmental monitoring, medical diagnostics, and industrial process control.&#xD., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Metallization for contacts in organic electronic nanodevices is of great importance for their performance. A lot of effects can appear at the contact/organic interface and modify the contact parameters, such as contact resistance, adhesive strength, and bonding ability. For novel materials, it is important to study the interactions with metal atoms to develop a suitable technology for contacts, fulfilling to the greatest extent the above-mentioned parameters. A novel material is carbyne, which is still under intensive research because of its great potential in electronics, especially for sensing applications. However, the most appropriate metallization strategy for carbyne-based devices is still unknown, so the interactions between carbyne and metal films should be studied to more precisely direct the development of the metallization technology, and to form contacts that are not limiting factors for device performance.

Liquid carbon remains the source of several unsolved questions related to its structure and region of thermodynamic stability. Experiments demonstrate a drastic decrease in the density for liquid carbon along the graphite melting line in the pressure range P = 1–3 GPa and the nature of this phenomenon is unclear. A recent experimental study [A.M. Kondratyev and A.D. Rakhel, PRL (2019)] revealed another peculiar and still unexplained feature of the liquid carbon – its excessive heat capacity. Using classical molecular dynamics with machine learning potential GAP-20, we study the structural properties of liquid carbon and demonstrate that at P < 1–2 GPa it resembles a net of sp -hybridized chains, rather than a typical covalent liquid, with nanoscale porosity of this phase being responsible for the density decrease. We also show that excessive heat capacity could be a direct manifestation of a smooth transition from a high-density sp 2-hybridized phase into a low-density sp -hybridized. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbyne, i.e. an infinitely long linear carbon chain (LCC), has been at the focus of a lot of research for quite a while, yet its optical, electronic, and vibrational properties have only recently started to become accessible experimentally thanks to its synthesis inside carbon nanotubes (CNTs). While the role of the host CNT in determining the optical gap of the LCCs has been studied previously, little is known about the excited states of such ultralong LCCs. In this work, we employ the selectivity of wavelength-dependent resonant Raman spectroscopy to investigate the excited states of ultralong LCCs encapsulated inside double-walled CNTs. In addition to the optical gap, the Raman resonance profile shows three additional resonances. Corroborated with DFT calculations on LCCs with up to 100 carbon atoms, we assign these resonances to a vibronic series of a different electronic state. Indeed, the calculations predict the existence of two optically allowed electronic states separated by an energy of 0.14–0.22 eV in the limit of an infinite chain, in agreement with the experimental results. Furthermore, among these two states, the one with highest energy is also characterized by the largest electron-vibration couplings, which explains the corresponding vibronic series of overtones. [Display omitted] [ABSTRACT FROM AUTHOR]

The low‐dimensional carbon allotropes have become a prominent topic of research due to their unprecedented strength and prospective physical properties. The Ar+ ion‐stimulated plasma deposition of the one‐dimensional carbon chains always presented a challenging task that still lacks a theoretical description. In this study, we propose a selective deposition quality criterion for the massive simulations planned to reveal the conditions for the synthesis of carbyne‐containing films, in particular, linear‐chained carbon by means of molecular dynamics. [ABSTRACT FROM AUTHOR]

Transistors made up of carbon nanotube CNT have demonstrated excellent current–voltage characteristics which outperform some high-grade silicon-based transistors. A continuously tunable energy barrier across semiconductor interfaces is desired to make the CNT-based transistors more robust. Despite that the direct band gap of the carbyne inside a CNT can be widely tuned by strain, the size of the carbyne cannot be controlled easily. The production of a monoatomic chain with more than 6000 carbon atoms is an enormous technological challenge. To predict the optimal chain length of a carbyne in different molecular environments, we have developed a Monte Carlo model in which a finite-length carbyne with a size of 4000–15,000 atoms is encapsulated by a CNT at finite temperatures. Our simulation shows that the stability of the carbyne@nanotube is strongly influenced by the nature and porosity of the CNT, the external pressure, the temperature, and the chain length. We have observed an initiation of the chain-breaking process in a compressed carbyne@nanotube. Our work provides much-needed input for optimizing the carbyne length to produce carbon chains much longer than 6000 atoms at ~300 K. Design rules are proposed for synthesizing ~1% strained carbyne@(6,5)CNT as a component in CNT-based transistors to tune the energy barriers continuously.

The reaction of a tungsten carbyne complex, MeC≡WBr(CO)4, with 1,6‐heptadiyne was investigated using density functional theory (DFT) calculations. It was suggested that the plausible mechanism involves [2+2] cycloaddition of the carbyne with the diyne, subsequent insertion of CO and alkyne into a metallacyclobutadiene intermediate, and a final reductive elimination step from a metallacycloheptatrienone intermediate to produce a η5‐cyclohexadienyl complex. A related Ru‐catalyzed reaction of 1,6‐heptadiyne involving a hydroxycarbyne complex was investigated to propose a possible pathway starting from a bis(hydroxycarbyne) complex, (HOC≡)2Ru(CO)2. It was found that the biscarbyne complex undergoes carbyne‐carbyne coupling to generate a stable metallacyclopropene intermediate, which reacts with 1,6‐heptadiyne through two different pathways to produce the final η6‐arene complex. Moreover, a non‐carbyne pathway was also investigated to propose an alternative mechanism. [ABSTRACT FROM AUTHOR]

The synthesis of carbyne has remained an elusive goal for decades. One of the significant reasons is that high-purity and high-concentration hydrogen end-capped polyynes (C 2n H 2) as the most important model molecule and precursors for carbyne have been not widely prepared. Herein, we develop a facile and universal strategy to obtain high-purity and high-concentration C 8 - 18 H 2 molecules using solid linear carbon chains with silver atom ending-capped (Ag 2 C 8-18) as reaction precursors. The purified and concentrated C 8 - 18 H 2 solution and Ag 2 C 8-18 powder are evaluated by a combination of X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, UV–vis–NIR spectroscopy and transmission electron microscope. These results confirm that the high-purity and high-concentration C 2n H 2 are obtained through the reaction of metal carbides solid and hydrogen chloride molecule. Our strategy for investigating unprotected linear carbon chains in solid and the successful preparation of high-concentration C 2n H 2 from solid carbides provide a new avenue for the research of linear carbon chains. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, a model of the surface layer of perfect single crystals is used and the role of surface energy in physical processes occurring in the region of nanosized carbon materials is clarified. Of these, diamond, graphite, carbyne and fullerenes have been investigated. The thickness of the surface layer of diamond with cubic symmetry is 8.2 nm and is a nanostructure. The average size of the synthesized nanodiamond is of the order of ~ 8 nm. The value of the surface energy σhkl calculated by us along the diamond planes (100), (110), and (111) is in good agreement with experiment and other calculations. The thickness of the surface layer of graphite along the a axis is equal to R(I)a = 8.0 nm and also represents a nanostructure. But along the c axis we have a layer thickness of about 1.5 nm and the number of monolayers is only 2. On this c axis, graphite can be created a monolayer by turning it into graphene. The σhkl value calculated by us along the a and c planes of graphite is 25957 and 5515 mJ/m², respectively. Carbines represent a polymeric polyyne or cumulene chain composed of sp-hybridized carbon atoms. If we imagine that the thickness of the surface layer of carbyne is stretched into a one-dimensional chain along the c axis, then the length of this chain is up to 200 nm for α-carbyne. The thickness of the surface layer of fullerenes significantly exceeds the thickness of the surface layer of pure metals. The surface energy of fullerenes σhkl increases with an increase in the number of carbon atoms c36 → c96. It also changes in the series (111) → (100) → (110). [ABSTRACT FROM AUTHOR]

Using density functional theory in combination with the Green's functional formalism, we study the effect of surface functionalization on the electronic transport properties of 1D carbon allotrope—carbyne. We found that both hydrogenation and fluorination result in structural changes and semiconducting to metallic transition. Consequently, the current in the functionalization systems increases significantly due to strong delocalization of electronic states along the carbon chain. We also study the electronic transport in partially hydrogenated carbyne and interface structures consisting of pristine and functionalized carbyne. In the latter case, current rectification is obtained in the system with rectification ratio up to 50%. These findings can be useful for developing carbyne-based structures with tunable electronic transport properties. [ABSTRACT FROM AUTHOR]

By using cathodic plasma electrolysis, a thin film of diamond-like carbon and carbyne was produced on the nickel surface. The ethanolic solution at different concentrations of 15, 30 and 50 vol% was used as the electrolyte; the produced carbon film was studied by using glow discharge optical emission spectroscopy, scanning electron microscopy, optical profilometer, and surface enhanced Raman scattering. The results proved the coating formation of 40-60 nm thick carbon materials on the nickel surface. The intensity ratio of carbyne band to the amorphous carbon structure band in the Raman spectroscopy was decreased from 1.o4 to 0.32 by an increase in ethanol concentration; this was related to the reduction at the carbyne and the increase of the diamond-like carbon content in the produced film. Also, the study of the samples surface showed an increase in the surface roughness from 520 to 750 nm by enhancing the ethanol concentration.

Quantum capacitance CQ of an infinite graphene sheet, a graphene nanoribbon, and a chain of carbon atoms (carbyne) have been analytically estimated within the framework of simple models. A nonmonotonic dependence of CQ on the electrostatic potential is demonstrated. The data obtained are compared with the calculation results of other researchers. [ABSTRACT FROM AUTHOR]

The "CPNR" ligand may be viewed as being isolobal with fulminate, CNO; however, attempts to prepare a complex of such a ligand resulted instead in a range of novel imino and aminophosphinocarbyne complexes. Sequential treatment of [Mo(≡CBr)(CO)2(Tp*)] (Tp*=hydrotris(dimethylpyrazolyl)borate) with nBuLi and ClP=NMes* (Mes*=C6H2tBu3‐2,4,6) afforded mixtures of the complexes [Mo(≡CPnBuNHMes*)(CO)2(Tp*)] and traces of the bimetallic products [Mo2{μ2‐C2P2O(NHMes)2}(CO)4(Tp*)2] and [Mo2(μ2‐C2PNHMes)(CO)4(Tp*)2]. The reaction of [W(≡CBr)(CO)2(Tp*)] with nBuLi and ClP=NMes* afforded predominantly the mononuclear carbyne [W{≡CP(=NMes*)nBu2})(CO)2(Tp*)] and traces of the binuclear complex [W2(μ‐C2PNHMes)(CO)4(Tp*)2] which is also obtained when tBuLi is used. Although not isolable, the intended complexes [M(≡CPNMes*)(CO)2(Tp*)] could be generated in situ and spectroscopically characterized via the reactions of the stannyl carbynes [M(≡CSnnBu3)(CO)2(Tp*)] and ClP=NMes*. The preceding observations are mechanistically interpreted with reference to a computational interrogation of the model complex [Mo(≡CP=NCH3)(CO)2(Tp*)], the LUMO of which has considerable phosphorus character. [ABSTRACT FROM AUTHOR]

We computationally investigate the hydrogen storage properties of carbyne C 10 -ring structure on either D nh or D (n/2)h symmetry decorated with calcium (Ca) atoms adsorbed on its outer surface. The calculations are carried out on DFT-GGA-PW91 and DFT-GGA-PBE levels of theory as implemented in Biovia Materials Studio modeling and simulation software. To account for van der Waals interactions we also carried out calculations using DFT-D method of Grimme. Dmol3 is used to calculate total energies, HOMO-LUMO electronic charge density, Mulliken population analysis, and electrostatic potential fitting charges (ESP). Based on these results: i) the average binding energy of Ca atom doping to C 10 -ring is ~2.3 eV (PW91) and ~2.1 eV (PBE). ii) Up to seven H 2 molecules per Ca atom can be physically adsorbed with an average energy of ~0.2 eV per H 2 molecule. iii) This physisorption leads to 8.09 wt percentage (wt. %) for the gravimetric storage capacity. According to these results, calcium-decorated carbyne C 10 -ring structure is excellent candidate for hydrogen storage at ambient conditions with application to fuel cells. • Hydrogen storage on C 10 -ring (cumulene/polyyne) decorated with Ca atoms, has been evaluated using DFT calculations. • The binding energy of adsorbed Ca atoms (~2.3 eV (PW91) and ~2.1 eV (PBE)) avoids metal clustering. • CaC 10 complex stores 8.09 wt% H 2 with an average binding energy of ~0.2 eV/H 2. • Equilibrium pressure for CaC 10 –7H 2 system (18–37 MPa), by means of adsorption isothermal calculations. [ABSTRACT FROM AUTHOR]

Carbon-based cyclic molecules with alternating polycyclic regions and double carbon chains referred to as carbon nanobracelets are studied using spin-polarized density functional theory (DFT) calculations with PBE functional. Optimized structure of considered nanobracelets consisting of 1–5 identical monomers with and without hydrogen atoms at the edge of polycyclic regions is found to have highest possible symmetry and bond length alternation in chains. Nanobracelets consisting of odd number of monomers have lower HOMO energy, greater HOMO-LUMO gap and greater bond length variation in the carbon atomic chains than nanobracelets with even number of monomers. [Display omitted] • Cyclic molecules with alternate aromatic regions and double carbon chains are studied. • Alternation of short and long bond in chains of carbon nanobracelets is observed. • All considered carbon nanobracelets have the highest possible symmetry. • Difference in properties of nanobracelets with even and odd monomer number is found. • Hydrogen at aromatic region enhances the redistribution of electron density within monomer. [ABSTRACT FROM AUTHOR]

Abstract An approach is developed to predict stability of carbyne-based nanodevices. Within this approach, the thermo-fluctuation model of instability and break of contact bond in nanodevices, containing carbyne chains and graphene sheets, is offered. Unlike the conventional models, it does not include empirical constants. The results of DFT calculations are used as initial data for this model. Possibility of synergistic effect of temperature and mechanical load on stability and value of service time of carbyne-based nanodevices is predicted. It is ascertained, that this synergism results in a significant (by many orders of magnitude) decrease in the lifetime of nanodevices containing carbyne chains. The atomic mechanism of this phenomenon is outlined. Conditions of thermo-force loading are predicted at which a service time of these devices is sufficient for applications.

In the article we introduce the experiment of the photostimulation effect in the tunneling conductivity of free-standing thin carbyne-gold films. We observe a sharp increase of the conductivity of hybrid film due to the electromagnetic exciting at the frequencies which are close to the plasmon resonance of gold nanoparticles. The use of carbyne threads as a stabilizing matrix makes it possible to obtain free-standing thin films that demonstrate a good structural stability. The tunnel current–voltage measurements demonstrate a strong dependence of the current value on the intensity of green laser radiation used to photostimulate thin C–Au in area of the measuring experiment. [ABSTRACT FROM AUTHOR]

Monoatomic carbon chains and carbyne-rich composites are promising materials for many applications from protective coatings to nanoelectronic devices. Therefore, a thorough understanding of both the atomic and electronic structure of chained carbon is important. In this study, a combination of Raman scattering and electron photoemission techniques is used to study the bonding types, electron work functions and band gaps for carbyne-containing films on copper and silicon substrates. Raman mapping shows the nonuniform distribution of sp1 hybridization across the carbon-coated area on polycrystalline copper substrate due to adhesion differences. UV-excited electron emission dependence on thickness and ambient pressure confirms the difference between the silicon- and copper-based samples. Comparison with DFT calculations performed on surface slab models allows to draw conclusions about the chained composite structure. Image 106 [ABSTRACT FROM AUTHOR]

Synthetic routes to dimetallated Cx carbon wires in which two metals are separated by a linear carbon chain involving terminal metal–carbon triple bonds are described for the complexes [(Tp*)(CO)2W≡C−(C≡C)n−C≡W(CO)2(Tp*)] (Tp*=hydrotris(dimethylpyrazolyl)borate) where n=1, 3 or 4, joining the previously known examples with n=0, 1 and 2 to complete the series as models for linear carbyne C∞. [ABSTRACT FROM AUTHOR]

The first examples of bi‐ and polynuclear tellurocarbonyl complexes were obtained from the reactions of [W(≡CTe)(CO)2(Tp*)]NEt4 (Tp*=hydrotris(dimethylpyrazolyl)borate) with [MCl(PCy3)]/TlPF6 (M=Cu, Au) or [Au2Cl2(μ‐dppm)], which afford [WM(μ‐CTe)(PCy3)(CO)2(Tp*)] (M=Cu, Au) and [WAu2(μ‐CTe)(μ‐dppm)(CO)2(Tp*)]3(PF6)3. In all cases it is specifically the tellurocarbonyl that assumes a bridging, but in each case distinct, role including examples of isotellurocarbonyl, semi‐bridging and σ–π coordination and combinations thereof. Tetrametallic complexes bridged by C2Te and C2Te2 ligands are also described. [ABSTRACT FROM AUTHOR]

Carbon films 50–180 nm thick on nickel substrates are fabricated by the ion sputtering of graphite and the deposition of heavy hydrocarbons from the gas phase with simultaneous electron irradiation. Irradiation results in the formation of bonds in carbon films due to the sp and sp3 hybridization of orbitals (sp and sp3 bonds), mainly, sp3 bonds. A fraction of these bonds does not change with growth in the electron energy; it increases three-fold with a reduction in the temperature and an increase in the electron current density. Electron irradiation enhances the film microhardness which exceeds 12 GPa. The films, prepared by heavy hydrocarbon deposition, contain CHn bonds and a small fraction of sp3 bonds. The maximum value of the microhardness of the hydrocarbon films is no more than 4.5 GPa. The analysis of the proposed model of the kinetics of forming different allotropic phases in a carbon film to be deposited shows that a temperature reduction changes the specific volume of an atom in the lattice, while under conditions of simultaneous electron irradiation, it appreciably increases the content of the phase with sp3 bonds. The effect of spi-bond breakage during electron-beam-assisted deposition weakly depends on the electron energy. The weak excitations of electrons of carbon atoms can also result in the formation of sp3 bonds and increases their concentration with growth in the electron current density. [ABSTRACT FROM AUTHOR]

Treatment of the SiMe3‐protected dichloro‐rhenium carbyne complexes Re{≡CCH=C(R)C≡CSiMe3}Cl2(PMe2Ph)3 (R = CMe3, 1‐adamantyl) with CsF in methanol directly afforded the 12‐membered metallacycles {ReCl(PMe2Ph)3}2{≡CCH=C(R)C≡C−}2. The electronic structure of the metallacycle was investigated by density functional calculations. The UV‐vis spectrum of the metallacycle shows a red‐shifted band compared to that of the starting dichlorocarbyne complex. Treatment of {ReCl(PMe2Ph)3}2{≡CCH=C(CMe3)C≡C−}2 with HCl produced the dichloro‐rhenium carbyne complex Re{≡CCH=C(CMe3)C≡CH}Cl2(PMe2Ph)3, which is consistent with the electronic structure of the 12‐membered metallacycles. Dirhenadehyro[12]annulenes were directly produced from the SiMe3‐protected dichloro‐rhenium carbyne complexes Re{≡CCH=C(R)C=CSiMe3}Cl2(PMe2Ph)3 (R = CMe3, 1‐adamantyl) by treatment with CsF in methanol (see scheme). The UV‐vis spectrum of the 12‐membered metallacycle display a red‐shifted band compared with that of the starting dichlorocarbyne complex. [ABSTRACT FROM AUTHOR]

Abstract Single atomistic chains of carbon – a.k.a. carbyne – are of great interest due to their attractive properties. One route of proposed synthesis is exploiting the interior of a carbon nanotube, enabling sufficient alignment and affable temperature conditions for chain growth. Here, we delineate the optimal conditions for growth by means of full atomistic modeling of sequential carbon reactions inside single walled carbon nanotubes (SWCNTs). Seeding the interior of a SWCNT with free carbons, we vary the nanotube diameters and temperature, and compare the resulting chain lengths. We systematically study the affecting factors of carbyne synthesis, investigating the effects of temperature, confinement (via nanotube diameter) and alignment (using polymer shape metrics). We verify with prior experimental studies that carbyne can be successfully synthesized when the inner diameter is less than approximately 9 Å and temperature is higher than 500 K. Additionally, we map the chain length with respect to the nanotube diameter and the temperature and propose a simple empirical/phenomenological relation to predict growth rate based on classical collision theory with a modified Arrhenius relation. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Carbyne, an infinite carbon chain, has attracted much interest and induced significant controversy for many decades. Recently, the presence of linear carbon chains (LCCs), which were confined stably inside double‐wall carbon nanotubes (DWCNTs) and multiwall carbon nanotubes (MWCNTs), has been reported. In this study, we present a novel method to produce LCCs in a film of carbon nanotubes (CNTs). Our transmission electron microscopy and Raman spectroscopy revealed the formation of a bulk amount of LCCs after electric discharge of CNT films, which were used as field emission cathodes. The LCCs were confined inside single‐wall CNTs as well as DWCNTs. Furthermore, two or three LCCs in parallel with each other are encapsulated when the inner diameter of CNT is larger than approximately 1.1 nm. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials, such as carbon nanotubes (CNTs), graphene sheets (GSs), and carbyne, are an important new class of technological materials, and have been proposed as nano-mechanical sensors because of their extremely superior mechanical, thermal, and electrical performance. The present work reviews the recent studies of carbon nanomaterials-based nano-force and nano-mass sensors using mechanical analysis of vibration behavior. The mechanism of the two kinds of frequency-based nano sensors is firstly introduced with mathematical models and expressions. Afterward, the modeling perspective of carbon nanomaterials using continuum mechanical approaches as well as the determination of their material properties matching with their continuum models are concluded. Moreover, we summarize the representative works of CNTs/GSs/carbyne-based nano-mass and nano-force sensors and overview the technology for future challenges. It is hoped that the present review can provide an insight into the application of carbon nanomaterials-based nano-mechanical sensors. Showing remarkable results, carbon nanomaterials-based nano-mass and nano-force sensors perform with a much higher sensitivity than using other traditional materials as resonators, such as silicon and ZnO. Thus, more intensive investigations of carbon nanomaterials-based nano sensors are preferred and expected.

Linear strings of sp1-hybridized carbon atoms are considered as a possible phase of carbon since decades. Whereas the debate about the stability of the corresponding bulk phase carbyne continues until today, the existence of isolated chains of carbon atoms has meanwhile been corroborated experimentally. Since graphene, as the two-dimensional sp2-bonded allotrope of carbon, has become a vast field, the question about the importance of one-dimensional carbon became of renewed interest. The present article gives an overview of the work that has been carried out on chains of carbon atoms in the past one or two decades. The review concentrates on isolated chains of carbon atoms and summarizes the experimental observations to date. While the experimental information is still very limited, many calculations of the physical and chemical properties have been published in the past years. Some of the most important theoretical studies and their importance in the present experimental situation are reviewed.

Unusual carbonaceous matter, termed here chiemite, composed of more than 90% C from the Alpine Foreland at Lake Chiemsee in Bavaria, southeastern Germany has been investigated using optical and atomic force microscopy, X‐ray fluorescence spectroscopy, scanning and transmission electron microscopy, high‐resolution Raman spectroscopy, X‐ray diffraction and differential thermal analysis, as well as by δ13C and 14C radiocarbon isotopic data analysis. In the pumice‐like fragments, poorly ordered carbon matter co‐exists with high‐ordering monocrystalline α‐carbyne, and contains submicrometer‐sized inclusions of complex composition. Diamond and carbyne add to the peculiar mix of matter. The required very high temperatures and pressures for carbyne formation point to a shock event probably from the recently proposed Holocene Chiemgau meteorite impact. The carbon material is suggested to have largely formed from heavily shocked coal, vegetation like wood, and peat from the impact target area. The carbonization/coalification high PT process may be attributed to a strong shock that instantaneously caused the complete evaporation and loss of volatile matter and water, which nevertheless preserved the original cellular structure seen fossilized in many fragments. Relatively fresh wood encapsulated in the purported strongly shocked matter point to quenched carbon melt components possibly important for the discussion of survival of organic matter in meteorite impacts, implying an astrobiological relationship. [ABSTRACT FROM AUTHOR]