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The significant synthetic potential and reactivity of tetracyanoethylene (TCNE) have captured the interest of numerous chemical communities. One of the most promising, readily achievable, yet least explored pathways for the reactivity of TCNE involves its interaction with arylamines. Typically, the reaction proceeds via tricyanovinylation (TCV); however, deviations from the standard chemical process have been observed in some instances. These include the formation of heterocyclic structures through tricyanovinyl intermediates, aliphatic dicarbonitriles through the cleavage of the C–C bond of a tetracyanoethyl substituent, complexation, and various pericyclic reactions. Therefore, the objective of this study is to review the diverse modes of interaction of TCNE with aromatic nitrogen-containing compounds and to focus the attention of the chemical community on the synthetic capabilities of this reagent, as well as the various biological and optical activities of the structures synthesized based on TCNE. [ABSTRACT FROM AUTHOR]

Low-energy (0–15 eV) resonance electron interaction with isolated tetracyanoethylene (TCNE) molecules is studied in vacuo by means of dissociative electron attachment (DEA) spectroscopy. Despite this molecule being relatively small, the long-lived molecular anions TCNE− are formed not only at thermal electron energy via a vibrational Feshbach resonance mechanism but also via shape resonances with the occupation of the π4* and π5* molecular orbitals by an incident electron. Dissociative decays of TCNE− are mostly observed at incident electron energy above the π7* temporary anion state predicted to lie at 1.69 eV by means of B3LYP/6-31G(d) calculations combined with the empirical scaling procedure. Electron attachment to the π6* orbital (predicted at 0.85 eV) leads to the generation of long-lived TCNE− species, which can decay via two competing processes: extra electron detachment, which appears in hundreds of microseconds, or elimination of two cyano groups to form the [TCNE − 2(CN)]− negative fragment on a tens of microsecond timescale. The latter is accompanied by the generation of a highly toxic cyanogen molecule as a neutral counterpart. Since the electron transfer to the acceptor molecule TCNE plays a key role in the formation of single-molecule magnets, the present data are of importance to understand the long-term behavior and likely harmful effects produced by cyanide-based prospective materials. [ABSTRACT FROM AUTHOR]

A cavity‐magnonic system composed of a superconducting microwave resonator coupled to a magnon mode hosted by the organic‐based ferrimagnet vanadium tetracyanoethylene (V[TCNE]x) is demonstrated. This work is motivated by the challenge of scalably integrating a low‐damping magnetic system with planar superconducting circuits. V[TCNE]x has ultra‐low intrinsic damping, can be grown at low processing temperatures on arbitrary substrates, and can be patterned via electron beam lithography. The devices operate in the strong coupling regime, with a cooperativity exceeding 1000 for coupling between the Kittel mode and the resonator mode at T≈0.4 K, suitable for scalable quantum circuit integration. Higher‐order magnon modes are also observed with much narrower linewidths than the Kittel mode. This work paves the way for high‐cooperativity hybrid quantum devices in which magnonic circuits can be designed and fabricated as easily as electrical wires. [ABSTRACT FROM AUTHOR]

The significant synthetic potential and reactivity of tetracyanoethylene (TCNE) have captured the interest of numerous chemical communities. One of the most promising, readily achievable, yet least explored pathways for the reactivity of TCNE involves its interaction with arylamines. Typically, the reaction proceeds via tricyanovinylation (TCV); however, deviations from the standard chemical process have been observed in some instances. These include the formation of heterocyclic structures through tricyanovinyl intermediates, aliphatic dicarbonitriles through the cleavage of the C–C bond of a tetracyanoethyl substituent, complexation, and various pericyclic reactions. Therefore, the objective of this study is to review the diverse modes of interaction of TCNE with aromatic nitrogen-containing compounds and to focus the attention of the chemical community on the synthetic capabilities of this reagent, as well as the various biological and optical activities of the structures synthesized based on TCNE.

In this paper, the nature of interactions between two cyanocarbons—tetracyanoethylene (TCNE) and fumaronitrile (FN)—and a series of four secondary amines possessing a general formula C4HxN (x = 5–11) is thoroughly scrutinized. For all of the TCNE–amine pairs, tricyanovinylation (TCV) reaction is observed; however, only for pyrrole, it is accompanied with a visible charge-transfer (CT) complex formation—no such chemical individuals, characteristic for TCNE, have been noticed for aliphatic and alicyclic amines. On the contrary, FN forms such complexes with all the amines studied. Interestingly, a rather unexpected reaction of FN with alicyclic amines has been observed. The recorded electron paramagnetic resonance (EPR) spectra indicate the presence of both TCNE●− and FN●− radicals in the analyzed samples, assigned to a complete charge (electron) transfer process within the CT complexes, whose efficiency can be additionally enhanced by photoirradiation. The origination of the former radical, whose presence is observed also in the TCNE–diethylamine mixture, is as well proposed to result indirectly from the TCV reaction, occurring for this system. Finally, the superhyperfine structure of EPR spectra, indicating the existence of some secondary interactions of the radicals with surrounding compounds, is discussed. Formation of CT complexes and tricyanovinylates has been investigated and characterized with UV–Vis spectroscopy, while the presence of (cyano)radicals in the analyzed mixtures has been evidenced by (photoinduced) EPR measurements. Interpretation of the experimental results is also supplemented with computer simulations including density functional theory calculations. [ABSTRACT FROM AUTHOR]

Tetracyanoethylene reacts with Se2Cl2, SO2Cl2 and catalytic BnEt3NCl in 1,2-dichloroethane heated at ca. 70 °C for 40 h to give 4,6-dichloropyrrolo[2,3-c][1,2,6]selenadiazine-5-carbonitrile (42%) and 4-chloro-6-oxo-6,7-dihydropyrrolo[2,3-c][1,2,6]selenadiazine-5-carbonitrile (30%). A chromatography free procedure allows isolation of 4,6-dichloropyrrolo[2,3-c][1,2,6]selenadiazine-5-carbonitrile in 70% yield. Regioselective displacement of the 6-chloro by O- and N-nucleophiles is demonstrated. Treatment of 4-chloro-6-morpholinopyrrolo[2,3-c][1,2,6]selenadiazine-5-carbonitrile with morpholine gives a low yield of the 4,6-dimorpholinopyrrolo[2,3-c][1,2,6]selenadiazine-5-carbonitrile (8%) together with 2,5-dimorpholino-3-oxo-3H-pyrrole-4-carbonitrile (13%) and 3,5-dimorpholino-2-oxo-2H-pyrrole-4-carbonitrile (55%). [ABSTRACT FROM AUTHOR]

This study shows the first example of cycloaddition–retro‐electrocyclization (CA‐RE) click reaction involving nitrogen end‐capped push‐pull oligoynes. The reported CA‐RE reaction with TCNE (tetracyanoethylene) is fully regioselective and leads exclusively to the unprecedented TCBD (tetracyanobuta‐1,3‐diene‐2,3‐diyl) end‐capped carbon rods. The molecular structure of the products was unambiguously confirmed using X‐ray single crystal diffraction and their optical and electronic properties were investigated experimentally and rationalized using DFT (density functional theory) calculations. [ABSTRACT FROM AUTHOR]

The possibility of coding the response of the electron–nuclear system of the tetracyanoethylene radical under microwave pulse irradiation in combination with a pulsed magnetic field gradient in the nanosecond timescale by a binary code is demonstrated. To this end, the tetracyanoethylene radical, which has a well-resolved equidistant electron paramagnetic resonance spectrum due to the interaction of the electron with equivalent magnetic nuclei, is used. The aim is to demonstrate the possibility of implementing this procedure physically rather than to encode the longest possible sequence. [ABSTRACT FROM AUTHOR]

Organic donor‐acceptor (DA) complexes have emerged in recent years as materials of choice for organic binary electronics. The reactivity descriptors derived from the conceptual DFT reveal imidazo[1,2‐a]pyridines as potential donors. Thus, four imidazo[1,2‐a]pyridines were reacted with tetracyanoethylene (TCNE) in 1 : 2 molar ratio to afford four new DA complexes. The spectral studies, namely IR, 1H, 13C, DEPT 135, 2D HMQC NMR, and HRMS were used to establish structures of the products. The UV‐vis. spectroscopy reveals intramolecular charge transfer. All the four compounds fluoresce giving excitation emission fluorescence spectra with a red shift ranging from 64 to 151 nm and quantum yields from 0.004 to 16.35. Unexpectedly, nitro group in one of the products does not act as quencher; instead, it enhances the quantum yield to make it highest in this series. The products exhibit electrical conductivity which increases with temperature. The FESEM and HRTEM images reveal distinct and homogenous surface morphology with holes which facilitate flow of electrons as manifested by electrical conductivity. The powder XRD and SAED results establish the polycrystalline nature of the products. The theoretical studies indicate an alternate donor acceptor stacking pattern. [ABSTRACT FROM AUTHOR]

The investigation of the biphenylene (BP)‐tetracyanoethylene (TCNE) π‐molecular complex is reported. The first study on this complex appeared in 1961 and was considered as a charge transfer complex with a symmetric, co‐planar arrangement of the components. Moreover, it was assumed that this arrangement is not only dictated by the formation of a Mulliken‐type donor‐acceptor complex, but also by the electronic stabilization of the 'cyclobutadieneoid' central ring of biphenylene through complex formation. Yet, crystal structure and associated computational analysis have not verified these predictions so far. We found that factors other than charge‐transfer interactions are most influential in the crystal formation. The low association constant in solution, and the weak interaction between the components in the 1 : 1 crystal structure point towards the low contribution of charge transfer interactions to their binding. Nevertheless, the presence of these interaction is hinted by the color of its solution and verified by theoretical calculations. Furthermore, Nucleus Independent Chemical Shift (NICS) calculations were carried out to characterize potential changes in the (anti)aromatic character of BP upon complex formation. The NICS(0) values of the rings of BP exhibit tiny changes both in the BP‐TCNE dimer and in the crystal, which also suggests weak electronic interactions between them. [ABSTRACT FROM AUTHOR]

1,1-Dimethylhydrazine (Heptil, rocket fuel (UDMH)) is characterized by extremely high toxicity, teratogenicity and the ability to constantly absorb water from the atmosphere, losing its energy characteristics. In this regard, as well as due to the alternative fuel ("Angara") transition, there is a need for UDMH utilization in huge amounts. A more benign approach involves its immediate reaction with a formalin solution to form 1,1–dimethyl-2-methylene hydrazone (MDH), which is significantly less toxic by an order of magnitude. MDH can then be polymerized under acidic conditions, and the resulting product can be burned, yielding a substantial amount of nitrogen oxides. We propose an alternative to incineration by involving MDH in organic synthesis. We studied the reactions of MDH and its analog N,N-dimethyl-2-(methylenamino)ethane-1-amine (MDEA) with available CH-acids: tetracyanoethylated ketones (TCEKs) based on cyclohexanone, 4-propylcyclohexanone, 2-methylcyclohexanone, cyclododecanone and tetracyanoethane. The structures synthesized were confirmed by IR, 1H, 13C NMR and mass spectroscopy methods. MDH-based adducts were also identified by X-ray structural analysis. TCEKs and MDH, as well as TCEK based on cyclohexanone and MDEA, form bi- and tricyclic structures: pyrrolo [3,4c]-quinolines (using TCEKs based on cyclohexanone and 4-propylcyclohexanone), epiminomethanoquinoline-3,4-dicarbonitrile (using TCEK based on 2-methylcyclohexanone) and cyclododec[b]pyran-3,4-dicarbonitrile (using TCEK based on cyclododecanone). MDH and TCNEH2 formed a pyrrole derivative. Thus, we synthesized the structures that are of interest for molecular design and pharmaceutical chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] Reaction between tetracyanoethylene and N,N -dimethyl-or N -(2-pyridyl)hydrazines affords 5-amino-3,4-dicyano-pyrazoles. In cases of aromatic amines, replacement of one cyano group by amino one occurs thus giving N -(tricyano-vinyl)anilines. [ABSTRACT FROM AUTHOR]

Copper and silver tritolylcorroles (TTC) are symmetrically functionalized to carry two tetracyanobutadiene (TCBD) entities via [2+2] cycloaddition‐retroeletrocyclization reaction involving ethynyl functionalized corroles with an electron acceptor, tetracyanoethylene (TCNE) in excellent yields, as the first examples of corrole‐TCBD push‐pull systems. The strong push‐pull effect resulted in charge polarization in the ground state resulting in a considerable hypsochromic shift of the spectrum extending it into the near‐IR region. Electrochemical studies coupled with computational studies revealed considerable interactions between the two TCBD entities via the corrole π‐system and the degree of such interactions was found to depend on the metal ion present in the corrole cavity. Energy considerations suggested charge transfer (CT) from the S2 or vibrationally hot S1 state but not the relaxed S1 state in the case of CuTTC(TCBD)2 while CT to occur from all these states in the case of AgTTC(TCBD)2. Additionally, the high‐energy CT states populate the low‐lying triplet states. Systematic femtosecond pump‐probe studies provided the ultimate proof for the occurrence of excited CT as a function of excitation wavelength followed by the efficient population of the triplet states. The present study brings out the significance of charge transfer in efficiently populating the triplet states in rather unusual copper and silver corroles carrying two TCBD entities. [ABSTRACT FROM AUTHOR]

The [2+2] cycloaddition ‐ retro‐electrocyclization (CA‐RE) reaction is a "click‐like" protocol for facile synthesis of donor‐acceptor chromophores from an alkyne and tetracyanoethylene. Herein we shed light on the mechanism of this reaction by detailed kinetics studies using 1H NMR spectroscopy. By considering several experiments simultaneously, a variety of mechanistic models was evaluated. Surprisingly, a model in which the final 1,1,4,4‐tetracyanobuta‐1,3‐diene product promoted the first step was the only one that described well the experimental data. This autocatalysis model also involved a non‐concerted, stepwise formation of the cyclobutene cycloaddition adduct. By proper choice of conditions, we were able to generate the transient cyclobutene in sufficient amount to verify it as an intermediate using 13C NMR spectroscopy. For its final retro‐electrocyclization step, simple first‐order kinetics was observed and only minor solvent dependence, which indicates a concerted reaction. [ABSTRACT FROM AUTHOR]

This review describes the design strategies used for the synthesis of various tetracyanobutadiene bridged donor‐acceptor molecular architectures by a click type [2+2] cycloaddition‐retroelectrocyclization (CA‐RE) reaction sequence. The photophysical and electrochemical properties of the tetracyanobutadiene bridged molecular architectures based on various moieties including diketopyrrolopyrrole, isoindigo, benzothiadiazole, pyrene, pyrazabole, truxene, boron dipyrromethene (BODIPY), phenothiazine, triphenylamine, thiazole and bisthiazole are summarized. Further, we discuss some important applications of the tetracyanobutadiene bridged derivatives in dye sensitized solar cells, bulk heterojunction solar cells and photothermal cancer therapy. [ABSTRACT FROM AUTHOR]

1,1-Dimethylhydrazine (Heptil, rocket fuel (UDMH)) is characterized by extremely high toxicity, teratogenicity and the ability to constantly absorb water from the atmosphere, losing its energy characteristics. In this regard, as well as due to the alternative fuel (“Angara”) transition, there is a need for UDMH utilization in huge amounts. A more benign approach involves its immediate reaction with a formalin solution to form 1,1–dimethyl-2-methylene hydrazone (MDH), which is significantly less toxic by an order of magnitude. MDH can then be polymerized under acidic conditions, and the resulting product can be burned, yielding a substantial amount of nitrogen oxides. We propose an alternative to incineration by involving MDH in organic synthesis. We studied the reactions of MDH and its analog N,N-dimethyl-2-(methylenamino)ethane-1-amine (MDEA) with available CH-acids: tetracyanoethylated ketones (TCEKs) based on cyclohexanone, 4-propylcyclohexanone, 2-methylcyclohexanone, cyclododecanone and tetracyanoethane. The structures synthesized were confirmed by IR, 1H, 13C NMR and mass spectroscopy methods. MDH-based adducts were also identified by X-ray structural analysis. TCEKs and MDH, as well as TCEK based on cyclohexanone and MDEA, form bi- and tricyclic structures: pyrrolo [3,4c]-quinolines (using TCEKs based on cyclohexanone and 4-propylcyclohexanone), epiminomethanoquinoline-3,4-dicarbonitrile (using TCEK based on 2-methylcyclohexanone) and cyclododec[b]pyran-3,4-dicarbonitrile (using TCEK based on cyclododecanone). MDH and TCNEH2 formed a pyrrole derivative. Thus, we synthesized the structures that are of interest for molecular design and pharmaceutical chemistry.

The cycloaddition of heptafulvalene (1) with tetracyanoethylene (TCNE) was previously described as an example of an antarafacial cycloaddition, a [π14a+π2s] process that afforded only the trans cycloadduct by virtue of the edge‐to‐face approach of TCNE, facilitated by the S shape of 1. The reaction has been investigated in depth and found not to be a concerted antarafacial process. At low temperature, the reaction is observed to give a mixture of cis and trans cycloadducts as well as a [4+2] cycloadduct. The mixture of products is converted to the trans cycloadduct by equilibration upon warming to room temperature. Studies with diethyl 2,3‐dicyanofumarate and ‐maleate confirmed the formation of cis cycloadducts. DFT studies at the M06‐2X/6‐311+G(2d,p) SCRF=acetone level of theory show that the originally proposed edge‐to‐face approach of TCNE to 1 is highly disfavored, whereas a stepwise mechanism involving the addition of TCNE at C2 to form a zwitterion followed by collapse at either C2′ or C7′ is energetically accessible. The Diels‐Alder adduct is also formed in a stepwise reaction by competitive addition of TCNE at C4 of 1. These studies suggest that edge‐to‐face interactions are prohibitive in even the most favorable cases. [ABSTRACT FROM AUTHOR]

The molecule-based ferrimagnetic semiconductor vanadium tetracyanoethylene (V[TCNE]x, x ≈ 2) has garnered interest from the quantum information community due to its excellent coherent magnonic properties and ease of on-chip integration. Despite these attractive properties, a detailed understanding of the electronic structure and mechanism for long-range magnetic ordering have remained elusive due to a lack of detailed atomic and electronic structural information. Previous studies via x-ray absorption near edge spectroscopy and the extended x-ray absorption fine structure have led to various proposed structures, and in general, V[TCNE]x is believed to be a three-dimensional network of octahedrally coordinated V2+, each bonded to six TCNE molecules. Here, we elucidate the electronic structure, structural ordering, and degradation pathways of V[TCNE]x films by correlating calculations of density functional theory (DFT) with scanning transmission electron microscopy and electron energy-loss spectroscopy (EELS) of V[TCNE]x films. Low-loss EELS measurements reveal a bandgap and an excited state structure that agree quantitatively with DFT modeling, including an energy splitting between apical and equatorial TCNE ligands within the structure, providing experimental results directly backed by theoretical descriptions of the electronic structure driving the robust magnetic ordering in these films. Core-loss EELS confirms the presence of octahedrally coordinated V+2 atoms. Upon oxidation, changes in the C1s-π* peak indicate that C=C of TCNE is preferentially attacked. Furthermore, we identify a relaxation of the structural ordering as the films age. These results lay the foundation for a more comprehensive and fundamental understanding of magnetic ordering and dynamics in these classes of metal–ligand compounds. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks linked by carbon-carbon double bonds (C=C COFs) are an emerging class of crystalline, porous, and conjugated polymeric materials with potential applications in organic electronics, photocatalysis, and energy storage. Despite the rapidly growing interest in sp2 carbon-conjugated COFs, only a small number of closely related condensation reactions have been successfully employed for their synthesis to date. Herein, we report the first example of a C=C COF, CORN-COF-1 (CORN = Cornell University), prepared by N-heterocyclic carbene (NHC) dimerization. In-depth characterization reveals that CORN-COF-1 possesses a two-dimensional layered structure and hexagonal guest-accessible pores decorated with a high density of strongly reducing tetraazafulvalene linkages. Exposure of CORN-COF-1 to tetracyanoethylene (TCNE, E1/2 = 0.13 V and -0.87 V vs. SCE) oxidizes the COF and encapsulates the radical anion TCNE•- and the dianion TCNE2- as guest molecules, as confirmed by spectroscopic and magnetic analysis. Notably, the reactive TCNE•- radical anion, which generally dimerizes in the solid state, is uniquely stabilized within the pores of CORN-COF-1. Overall, our findings broaden the toolbox of reactions available for the synthesis of redox-active C=C COFs, paving the way for the design of novel materials., (© 2024 Wiley‐VCH GmbH.)

We introduce a practical calculation scheme for the description of excited electron dynamics in molecular aggregate systems within a local group diabatic Fock representation. This scheme makes it easy to analyze the interacting time-dependent excitation of local sites in complex systems. In addition, lightelectron couplings are considered. The present scheme is intended for investigations on the migration dynamics of excited electrons in light-induced energy transfer systems. The schemewas applied to two systems: a naphthalene-tetracyanoethylene dimer and a 20-mer circle of ethylene molecules. Through local group analyses of the dynamical electrons, we obtained an intuitive understanding of the electron transfers between the monomers. [ABSTRACT FROM AUTHOR]

1,1,4,4‐Tetracyanobutadienes (TCBDs) bearing a large diversity of fluorophores were prepared following a multi‐step synthesis. In a crucial last step, all compounds were obtained from the corresponding ynamides, which were particularly suitable for the formation of the TCBDs in the presence of tetracyanoethylene via a [2+2] cycloaddition/retroelectrocyclization step (CA‐RE). Several fluorenyl derivatives in addition to phenanthrenyl and terphenyl ones provided ynamide‐based TCBDs affording remarkable emission properties covering a large range of wavelengths. Those compounds emit both in solid state and in solution from the visible region to the NIR range, depending on the molecular structures. Quantum yields in cyclohexane reached unforeseen values for such derivatives, up to 7.8 %. A huge sensitivity to the environment of the TCBDs has also been unraveled for most of the compounds since we observed a dramatic fall of the quantum yields when changing the solvent from cyclohexane to toluene, while they are almost non‐emissive in dichloromethane. [ABSTRACT FROM AUTHOR]

This work reports new studies of the activity and Diels–Alder kinetics of a series of dienophiles: tetracyanoethylene (1), 2,3‐dicyano‐p‐benzoquinone (10), and N‐phenylimide‐1,4‐benzoquinone‐2,3‐dicarboxylic acid (11). Rate differences are interpreted in terms of the donor–acceptor properties of the reagents. The relative π‐acceptor properties of the dienophiles are probed by measuring their interaction energies with a series π‐donor solvents: benzene, toluene, o‐xylene, and chlorobenzene. The normalized interaction energies of 1, 10, and 11 are found to be 100:64:28. Despite the increased energy of the donor–acceptor interaction, dienophile 10 is 255 times less active in the reaction with 9,10‐dimethylanthracene than 11. It is suggested that this is due to the significantly lower energy of π‐bond cleavage in bicyclic dienophile 11, compared with monocyclic 10. [ABSTRACT FROM AUTHOR]

Electrides are interesting and promising materials with cavity-trapped electrons which can be used as source of electron donor in different systems. Hereby, we have explored the possible formation of electride materials based on tetracyanoethylene (TCNE) backbone at MP2 computational level. This is achieved by systematic addition of up to four Na atoms to TCNE backbone. Our results predict high thermodynamic stability in the Nan@TCNE (n=1-4) systems. Moreover, based on the evaluation of four criteria, non-nuclear attractor (NNA), electron localization function (ELF), electron density laplacian (∇^2 ρ(r)), and non-linear optical (NLO), TCNE-Na1 and TCNE-Na2 and TCNE-Na4 species are conventional donor-acceptor systems (lithium salt). In contrast, the TCNE-Na3 species can be introduced as sodium electride with cavity-trapped electrons. Therefore, Na:TCNE ratio is very significant factor to provide species with electride feature through the addition of Na atoms to TCNE backbone.

[Display omitted] To utilize N,N -dimethylhydrazine, the corresponding +formaldehyde hydrazone was reacted with 1,1,2,2-tetra-cyanoethane or 3,3,4,4-tetracyanoalkanones. The first process yielded 5-amino-1-dimethylamino-1,2-dihydro-3 H -pyrrole-3,3,4-tricarbonitrile while the second afforded pyrrolo[3,4- c ]quinolone multifunctional derivatives. These resultant products hold promise in molecular design and pharmaceutical chemistry. [ABSTRACT FROM AUTHOR]

The recent successful synthesis of Pnnm -CN structure inspired researchers to explore new superhard 3D C–N compounds via a similar method, that is, high-pressure and high-temperature experiments involving carbon and nitrogen elements. Naturally, in some past high-pressure experiments involving C–N precursors, whether there are undiscovered C–N compounds in the product is worthy of being re-examined. This work proposed four novel carbon-rich C–N compounds, namely, r -C 17 N 4 , sc -C 4 N, sc -C 17 N 4 –I, and sc -C 17 N 4 -II, which possibly coexist with the unidentified simple cubic carbon phase in the shock compression products of the carbon black and tetracyanoethylene mixture. Most of the X-ray diffraction peaks from the experiment could be understood by the proposed C–N compounds. Furthermore, the calculations of formation enthalpies using experimental materials as precursors show that these four C–N compounds are more easily synthesized than the carbon structures previously used to explain the unknown phase. These phenomena indicate that C–N compounds might be synthesized in this experiment, not just the new carbon phase. The current study may provide a new idea for the experimental research of C–N compounds and inspire further research to reevaluate previous experimental findings. [Display omitted] [ABSTRACT FROM AUTHOR]

The hydrostatic pressure dependence of the magnetic ordering temperature, Tc(P), for the interpenetrating, diamondoid lattice-structured, weak ferromagnet (= canted antiferromagnet) Li+[TCNE]˙− (TCNE = tetracyanoethylene) reversibly increases from 20.9 to 23.4 K at 9.73 kbar, an increase of 12% with a rate of increase, dTc/dP, of 0.27 K kbar−1. The 5 T magnetization increased by 672% from 186 emu Oe mol−1 at ambient pressure to an average of 1440 emuOe mol−1 upon application of pressure. The remanent magnetization initially increases 30% from 10.8 to 14.0 emuOe mol−1 from ambient to 0.06 kbar, and increases further by 6% to a maximum of 14.8 emuOe mol−1 at 0.56 kbar before declining by 22% to 11.5 emuOe mol−1 at 9.73 kbar. The pressure-dependent coercive field, Hcr(P), initially decreases by 42% from 31.1 Oe at ambient pressure to 18 Oe at 0.06 kbar, then increases to 52 Oe at 9.73 kbar. The canting angle, α, increases by 28% from 0.52° to 0.66° at 0.06 kbar, then decreases by 23% to 0.51° at 9.73 kbar, as well as increases by 2% from 0.536° to 0.548° from 1.8 to 2.5 K, before decreasing by 79% to 0.117° at 19 K. The interlattice interactions are attributed to be the primary exchange mechanism. Thus, α(T) and α(P) have similar dependencies that are attributed to a competition between an increase and a decrease in the intra- and interlayer C⋯N interlattice separations as the temperature and pressure increases. [ABSTRACT FROM AUTHOR]

The deposition of tetracyanoethylene (TCNE) on Ag(111), both at Room Temperature (RT, 300 K) and low temperatures (150 K), leads to the formation of coordination networks involving silver adatoms, as revealed by Variable-Temperature Scanning Tunneling Microscopy. Our results indicate that TCNE molecules etch away material from the step edges and possibly also from the terraces, which facilitates the formation of the observed coordination networks. Moreover, such process is temperature dependent, which allows for different stoichiometric ratios between Ag and TCNE just by adjusting the deposition temperature. X-ray Photoelectron Spectroscopy and Density Functional Theory calculations reveal that charge-transfer from the surface to the molecule and the concomitant geometrical distortions at both sides of the organic/inorganic interface might facilitate the extraction of silver atoms from the step-edges and, thus, its incorporation into the observed TCNE coordination networks. [ABSTRACT FROM AUTHOR]

Luminescent β-diketone-based lanthanide complexes have been well explored as chemical sensor materials for biomedicine applications. Herein, three mononuclear Eu3+ complexes based on bis-β-diketone ligands (L1, L2 and L3) that can reduce luminescence quenching caused by water were developed. The ligands feature two β-diketone units covalently bound at the 1,8-position of the derivatized anthracene (modified with tetracyanoethylene, TCNE). X-ray crystallographic analysis reveals that their self-assemblies with Ln3+ ions in a 2 : 1 stoichiometric ratio form mononuclear anion complexes, [EuL2]−, in which two ligands coordinate to the metal center in a mutually orthogonal manner. This kind of arrangement together with the bulge of TCNE from the anthracene plane well protected the complexes from the quenching effects of water molecules in the second coordination. The photophysical measurements showed that the complexes not only had high luminescence quantum yields (QYs, up to 50–67%) but also presented excellent water-quenching resistant capability. [ABSTRACT FROM AUTHOR]

Organic‐based magnetic materials have been used for spintronic device applications as electrodes of spin aligned carriers and spin‐pumping substrates. Their advantages over more traditional inorganic magnets include reduced magnetic damping and lower fabrication costs. Vanadium tetracyanoethylene, V[TCNE]x (x ≈ 2), is an organic‐based ferrimagnet with an above room‐temperature magnetic order temperature (Tc ≈ 400 K). V[TCNE]x has deposition flexibility and can be grown on a variety of substrates via low‐temperature chemical vapor deposition (CVD). A systematic study of V[TCNE]x thin‐film CVD parameters to achieve optimal film quality, reproducibility, and excellent magnetic properties is reported. This is assessed by broadband ferromagnetic resonance (FMR) that shows most narrow linewidth of ≈1.5 Gauss and an extremely low Gilbert damping coefficient. The neat V[TCNE]x films are shown to be efficient spin injectors via spin pumping into an adjacent platinum layer. Also, under an optimized FMR linewidth, the V[TCNE]x films exhibit Fano‐type resonance with a continuum broadband absorption in the microwave range, which can be readily tuned by the microwave frequency. [ABSTRACT FROM AUTHOR]

Asymmetrical and symmetrical push-pull chromophore-based on triphenylamine (TPA) donors and naphthalenediimide (NDI) acceptors are designed and successfully synthesized via [2+2] cycloaddition-retroelectrocyclization (CA-RE) reaction with wellknown electron-accepting tetracyanoethylene (TCNE) and 7,7,8,8, -tetracyanoquinodimethane (TCNQ) groups. The novel series of compounds NDI-TPA-1 to NDI-TPA-6 were characterized to identify the influence of the TCNE and TCNQ π-conjugated linkers on the optical, electrochemical, and electronic properties of these molecules. We found that in dichloromethane the NDI-TPAs 1, 4, 5, and 6 display absorbance peaks at increasing wavelengths 605, 641, 646, and 645 nm, respectively. We demonstrated that through simple chemical modification we could drop the lowest occupied molecular orbital of NDI-TPA-1 to 6. Furthermore, NDI-TPA-1 to 6 were integrated into organic thin-film transistors (OTFTs) via spincoating technique, and charge transfer properties were investigated. We found that the choice of the functional group led to either p-type, n-type, or ambipolar characteristics. [ABSTRACT FROM AUTHOR]

• Designed and synthesized push-pull chromophores 3–8 through Pd-catalyzed reactions and cycloaddition-retro-electrocyclization with TCNE and TCNQ. • Achieved a second-time reaction with 1,1′-dialkynylferrocenes and TCNE/TCNQ, previously challenging. TCNQ-based derivatives exhibit red-shifted absorption compared to TCNE-based ones. • Acceptors red-shift absorption and reduce the HOMO-LUMO gap and studied the influence of conjugation length and acceptor strength on photophysical and electrochemical properties. Symmetrical and unsymmetrical donor-acceptor (D–A) based chromophores were designed and synthesized by the Pd–catalyzed Sonogashira cross–coupling reaction of 1,1′-diiodoferrocene with (4- N,N -dimethylaminophenyl)ethyne followed by [2+2] cycloaddition-retroelectrocyclization reaction with tetracyanoethylene (TCNE) or 7,7,8,8-tetracyanoquinodimethane (TCNQ). Ferrocene was used as a central donor unit and 4-(N,N -dimethylamino)phenyl group as the end-capping donor. Herein, we report the cycloaddition-retrocyclization reaction of TCNE/TCNQ groups on the disubstituted ferrocene containing more than one triple bond to get disubstituted tetracyanobutadiene (TCBD) and cyclohexa-2,5-diene-1,4-diylidene-expanded TCBD products. The effect of the conjugation length and different π–acceptor linkers were investigated by photophysical, redox and computational studies. The redox study reveals multiple oxidation waves corresponding to donor moieties (ferrocene and 4-(N,N -dimethylamino)phenyl group) and reduction waves corresponding to acceptor units (TCBD / cyclohexa-2,5- diene-1,4-diylidene-expanded TCBD). The thermogravimetric analysis data shows that the compounds exhibit high thermal stability. The computational studies reveal HOMO-LUMO gaps consistent with the experimentally obtained data. [Display omitted] [ABSTRACT FROM AUTHOR]

The rate of reactions in the solid phase with uniform grinding of crystals of dienes, anthracene, and 9,10‐dimethylanthracene, with dienophiles, tetracyanoethylene, N‐phenylmaleimide, and 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione, has been studied. It was shown that, despite the high difference in the reaction rates in solution, the rates of these reactions in the solid phase are much closer. For anthracene‐tetracyanoethylene and 9,10‐dimethylanthracene‐tetracyanoethylene pairs, it was concluded that their intermolecular complexes are on the reaction pathway. [ABSTRACT FROM AUTHOR]

Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular chargetransfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations. [ABSTRACT FROM AUTHOR]

In a recent paper in Chemistry – A European Journal, Nielsen and coworkers reported a deep study on the mechanism of the [2+2] cycloaddition‐retroelectrocyclization (CA‐RE) between an electron‐rich alkyne and tetracyanoethylene (TCNE), inducing the formation of a 1,1,4,4‐tetracyanobutadiene (TCBD). Following a robust kinetic study, the authors confirmed important intermediates and determined this reaction to be autocatalytic for the first time. Given the increasing use of TCBDs in the community and the strength of the CA‐RE reaction this paper offers important insights for future developments of this promising reaction. [ABSTRACT FROM AUTHOR]

Unlike the [3+2] cycloadduct of electron‐donating group (EDG)‐free alkynes with tetracyanoethylene oxide (TCNEO), the EDG induced [3+2] cycloadduct underwent one‐pot ring‐opening and deoxygenation reactions to provide the established EDG‐substituted non‐planar 1,1,4,4‐tetracyanobuta‐1,3‐dienes (TCBDs) push‐pull chromophores. This is an alternate synthetic method that provides access to TCBDs other than the [2+2] cycloaddition–retroelectrocyclization reactions with tetracyanoethene. [ABSTRACT FROM AUTHOR]

Aseries of cyclobutane-1,1,2,2-tetracarbonitriles contained a compound with significant activity against various cancer cell lines. The compound featured a thiosemicarbazide and the α,β-unsaturated aldehyde myrtenal in its structure and showed the highest activity against leukemia cells, the average growth inhibition against which was 88%. The proposed mechanism of action was associated with alkylation of the nucleophilic regions of tumor-cell DNA. The results showed that compounds with an ethyl-1,1,2,2-tetracarbonitrile fragment inhibited proliferation of malignant cells. [ABSTRACT FROM AUTHOR]

In this paper, we describe an efficient and atom‐economical synthesis of highly functionalized pyrroles, pentafulvenes, and pyrrolopyridines by [2+2] cycloaddition–retroelectrocyclization of N‐substituted propargylamines with tetracyanoethylene, followed by the treatment of the resulting tetracyanobutadiene derivatives with silica gel. In this reaction, silica gel plays an important role to promote the intramolecular cyclization to afford the heterocyclic products from the tetracyanobutadiene intermediates. The products were obtained selectively depending on the substituent on the nitrogen atom of the starting propargylamines. [ABSTRACT FROM AUTHOR]

The reaction between N-substituted alkenylidene hydrazinecarbothioamides and two molar amounts of tetracyanoethylene (TCNE) in anhydrous THF at room temperature without using any catalyst affords (Z)-4-amino-3-((Z)substituted amino)-2-(substituted imino)-2,3-dihydrothiazole-5-carbonitriles and (Z)-(4-amino-5-cyano-thiazol-2(3H)-ylidene)carbonhydrazonoyl dicyanides. Rationales for these transformations are presented. The structures of the obtained products were confirmed via single-crystal X-ray analyses. Here, we synthesize (Z)-4-amino-3-amino-2-imino-2,3-dihydrothiazole-5-carbonitriles and (Z)-(4-amino-5-cyano-thiazol-2(3H)-ylidene)carbonhydrazonoyl dicyanides from the reaction of N-substituted alkenylidene hydrazinecarbothioamides with (TCNE) in anhydrous THF at room temperature without using any catalyst. [ABSTRACT FROM AUTHOR]

• Studied the influence of encapsulation on the kinetics and thermodynamics of the Diels-Alder reaction. • Effects of binding pockets on the Diels-Alder reaction are explored by selecting CB n(n = 5–8) -uril. • CB6-uril has the lowest activation energy of ≈ 19.45 kcal mol−1, predicting CBn-uril as an effective cavity for researching the Diels-Alder process. Cucurbit-uril (CB-uril) family has witnessed a considerable increase in popularity over the last two decades due to its amazing binding ability which impart broad range of applications. Cucurbit-uril family members exhibit diversity in their binding pocket to accommodate guest molecules of different sizes which in turn impact the remarkable properties of these molecules. Herein, we have studied the influence of encapsulation on the kinetics and thermodynamics of the Diels-Alder reaction. Effects of binding pockets on the Diels-Alder reaction are explored by selecting CB n(n = 5–8) -uril. Bond evolution theory (BET) and non-covalent interaction (NCI) analyses have also been performed to gain insight into electronic distribution along the reaction route as well as bond formation/breakage to understand the mechanism of action and the role of weak/strong interactions between CBn-uril and reaction during the process. Activation energies for Diels-Alder reaction in CB n=6–8 -uril (22.63 kcal mol−1, 21.37 kcal mol−1, and 19.45 kcal mol−1, respectively) are significantly lower than that of the bare reaction (25.45 kcal mol−1). While for P-DA reactions, activation energies within CB n=7,8 -uril are observed as 19.29 kcalmol−1 and 14.45 kcalmol−1 (cis-1,2-dicyanoethylene), 18.46 kcalmol−1 and 14.65 kcalmol−1 (trans-1,2-dicyanoethylene), and 16.01 kcalmol−1 and 20.86 kcalmol−1 (tetracyanoethylene). CB7-uril has predicted the lowest activation energies for DA reaction with cis-1,2-dicyanoethylene and trans-1,2-dicyanoethylene compared to bare E a ≈ 20.15 kcalmol−1 and 19.57 kcalmol−1, respectively. By making the reaction more exothermic with E R ≈ -40 kcal mol−1, CB6-uril has the lowest activation energy of ≈ 19.45 kcal mol−1, predicting CBn-uril as an effective cavity for researching the Diels-Alder process. [Display omitted] [ABSTRACT FROM AUTHOR]

Nitrogen-doped porous carbon possesses widespread applications in energy-related fields due to its unique properties. However, preparation of porous carbon (specific surface area > 3000 m2 g–1) with high nitrogen content (> 10 wt%) remains great challenges because of high synthesis temperature. Herein, a covalent triazine polymer was innovatively designed by cyclotrimerization of tetracyanoethylene, and used to produce the high nitrogen-doped porous carbon. The as-prepared porous carbon (HNPC-900) possesses a high nitrogen content (14.2 wt%) and large specific surface area (3210 m2 g–1). When HNPC-900 was applied as the air-cathode for zinc–air batteries, it shows a high specific capacity (797 mAh g zn –1) and stable rechargeability (more than 380 h over 960 cycles at 5 mA cm–2), outperforming the cathode composed of RuO 2 and 20 wt% Pt/C. This ingenious design provides a feasible strategy to prepare high nitrogen-doped porous carbon, giving extensive application prospects of porous carbon for catalysis and energy storage fields. [Display omitted] • Tetracyanoethylene is used for preparing a new covalent triazine polymer (CTP). • HNPC derived from CTP possesses dual-superiority in N content and porosity. • HNPC exhibits excellent bifunctional electrocatalytic performances. • HNPC shows the recyclable ability for zinc–air battery. [ABSTRACT FROM AUTHOR]

Clotrimazole (CLZ) is an imidazole derivative that is therapeutically used as an antifungal drug. The routine control analysis of CLZ requires rapid, reliable, accurate and precise methods for the quantification of the drug in its pharmaceutical formulations. Spectrophotometric methods are presented for the determination of the antifungal agent that are based on the charge transfer complexation reaction of CLZ with the π-acceptors tetracyanoethylene (TCE) and 7,7′,8,8′-tetracyanoquinodimethane (TCNQ). The formation of coloured complexes was quantitated at 396 nm and 842 nm for CLZ-TCE and CLZ-TCNQ, respectively, which enabled the development of simple and accurate spectrophotometric methods for the analysis of CLZ in pure drug substances and its pharmaceutical products. Under the optimum reaction conditions, linear relationships with appreciable correlation coefficients (0.9985–0.9994) were found between the absorbance at the relevant maxima and the concentrations of CLZ in the range of 5.00–35.00 μg mL−1 for CLZ-TCE and 1.00–25.00 μg mL−1 for CLZ-TCNQ. The molar absorptivities and Sandell's sensitivity values were also statistically evaluated. The proposed methods were successfully applied to analyze CLZ in topical creams and sterile solutions with mean recovery percentages in the range of 99.60–100.20%, which indicated no interference from the inactive ingredients. Furthermore, the charge transfer complexes of CLZ were also characterized by FT-IR spectroscopy.

Using the structural and electronic tunability of molecules to control magnetism is a central challenge of inorganic chemistry. Herein, a ten-member family of the high-ordering temperature (Tc) molecule-based magnetic coordination networks of the form V[x-ClnPTCE]2·yCH2Cl2 (PTCE = phenyltricyanoethylene, y < 0.5) were synthesized and characterized, where x is (are) the position(s) and n is the number of chlorine substitutions on the phenyl ring. These chlorophenyltricyanoethelenes are tunable analogs of the more commonly investigated tetracyanoethylene (TCNE). Varying the number and position of chlorine substitution around the phenyl ring engendered a family of network solids with significantly different magnetic ordering temperatures ranging from 146 to 285 K. The Tcs of these ferrimagnets were rationalized with the aid of cyclic voltammetry and Density Functional Theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Tetracyanoethylene adducts with ketones, 4-oxoalkane-1,1,2,2-tetracarbonitriles reacted with hydrogen chloride or phosphorus(III) chloride in 1,4-dioxane to give 3-chloro-6-oxo-2,7-diazabicyclo[3.2.1]oct-3-ene-4,5-dicarbonitrile derivatives. [ABSTRACT FROM AUTHOR]

Abstract A novel approach to 2-amino-3,4-dicyanopyridines has been discovered from Cu(I)-catalyzed cyclizations of simple and easily available ketoximes and tetracyanoethylene (TCNE). The complexed radical mechanism involves cleavage of several O H/N O/C H bonds, and new C C/C N bonds formation. A wide variety of substrates with different functional groups could be smoothly converted into the corresponding products in moderate yields. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Tetracyanoethylene adducts of cycloalkanones, 1-(2-oxocycloalkyl)ethane-1,1,2,2-tetracarbonitriles, reacted with aqueous ammonia at room temperature to give, depending on the cycloalkane ring size and reaction conditions, three types of nitrogen-containing heterocyclic compounds. The reaction of tetracyanoethylene-cyclohexanone adducts with 20–25% aqueous ammonia afforded 10,11-diazatricyclo[5.3.2.01,6]-dodec-8-ene derivatives, whereas their seven- and eight-membered analogs were converted to pyrrolo[3,4-c]-pyridines under similar conditions. Treatment of 1-(2-oxocyclooctyl)ethane-1,1,2,2-tetracarbonitrile with 10–15% aqueous ammonia led to the formation of 2,5-diamino-3-(2-oxocyclooctyl)-3H-pyrrole-3,4-dicarbonitrile as a mixture of two diastereoisomers. [ABSTRACT FROM AUTHOR]

Highlights • The interaction of a graphene monolayer with CO 2 and CH 4 was investigated. • the result show that CO 2 and CH 4 interact weakly with graphene surface. • a TCNE molecule was used to reduce the electron accumulation on the graphene. • the adsorption energies of CO 2 and CH 4 are very large in the presence of TCNE. Abstract Density functional theory calculations are implemented to study the interaction of CO 2 and CH 4 molecules with an intrinsic graphene and a tetracyanoethylene (TCNE) modified graphene surface. The strength of the interactions is investigated by the adsorption energies (E ads) of the molecules on the graphene surface and the changes of the electronic structures (especially by HOMO/LUMO energy gap (E g)) of graphene. The analysis of E ads shows that the interaction of both CO 2 and CH 4 with TCNE modified graphene is more favorable. It is assumed that a TCNE molecule can affect the interactions of the molecules with the graphene sheet by reducing the charge accumulation over the graphene surface. However, despite the increase in the strength of interactions, the changes in the electronic properties of both intrinsic and modified graphene is not high enough to consider them as a potential CO 2 or CH 4 gas detector. However, the considerable amount of E ads in TCNE modified graphene might be a guide to the design of graphene-based adsorbents of CO 2 and CH 4 molecules. [ABSTRACT FROM AUTHOR]

The kinetics of reaction of phenylnitroso oxide and a number of its para-substituted analogues (R = Me2N, MeO, Me, and Br) with tetracyanoethylene in acetonitrile at room temperature was studied using flash photolysis. It was established that nitroso oxides exhibited nucleophilic properties in this reaction, and the rate constants for the trans forms of these species in the above series changed by seven orders of magnitude. In the presence of a strong electron-donating substituent (Me2N or MeO), the cis form, which is usually inert toward organic substrates, also reacted with the olefin along with the trans form. The reaction mechanism was studied using the density functional theory. [ABSTRACT FROM AUTHOR]

The effects of high hydrostatic pressure, temperature, and solvent on the rates of reactions of tetracyanoethylene (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (2) with 3,4-dihydro-2Hpyran (3) were studied. The X-ray diffraction analysis showed that the reaction of compounds 1 and 3 occurs with the formation of the cyclobutane adduct. The reaction is characterized by enhanced entropy and activation volume, as well as a high influence of the solvent polarity (ET) on the rate (R = 0.975). The course of the reaction 2 + 3 differs sharply from the reaction 1 + 3 by the values of entropy and activation volume, the absence of the effect of the solvent polarity on the rate, and the presence of mono-, di-, and trimeric reaction products. Possible routes of these reactions are considered. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Li n @TCNE (n = 1–4) systems have high thermodynamic stability. • Li n @TCNE (n = 1,2,4) systems are lithium salt without cavity-trapped electrons. • Li 3 @TCNE system is lithium electride with cavity-trapped electrons. • Li:TCNE ratio is an important factor in Li n @TCNE (n = 1–4) systems. Abstract Electrides are interesting and promising materials with cavity-trapped electrons which can be used as source of electron donor in different systems. Hereby, we have explored the possible formation of electride materials based on tetracyanoethylene (TCNE) backbone at MP2 computational level. This is achieved by systematic addition of up to four Li atoms to TCNE backbone. Our results predict high thermodynamic stability in the Li n @TCNE (n = 1–4) systems. Moreover, based on the evaluation of four criteria, non-nuclear attractor (NNA), electron localization function (ELF), electron density laplacian ( ∇ 2 ρ (r)) , and non-linear optical (NLO), TCNE-Li 1 and TCNE-Li 2 and TCNE-Li 4 species are conventional donor-acceptor systems (lithium salt). In contrast, the TCNE-Li 3 species can be introduced as lithium electride with cavity-trapped electrons. Therefore, Li:TCNE ratio is very significant factor to provide species with electride feature through the addition of Li atoms to TCNE backbone. [ABSTRACT FROM AUTHOR]