Isotropic Three-Dimensional Molecular Conductor Based on the Coronene Radical Cation (original) (raw)
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Structural and electronic properties of halogenated coronene
Journal of Molecular Structure: THEOCHEM, 2001
The structural and electronic properties of halogenated coronenes, (C 24 X 12 ; X F, Br, I), have been investigated theoretically by performing semiempirical molecular orbital theory at the level of AM1-RHF calculations. The optimized geometries and the electronic structures of the molecules considered have been obtained.
Crystal Growth & Design, 2016
Electrochemical oxidation of a polycyclic aromatic hydrocarbon, coronene, with D6h symmetry in the presence of tetrahedral GaCl4anions gave two cation salts, (coronene)(GaCl4) (1) and (coronene)5(GaCl4)2 (2), with unprecedented charge arrangements. Salt 1 involves π-stacking columns in a zigzag manner, which are composed of crystallographically equivalent coronene monocations. First-principle calculations revealed that the dimerization of coronene cations gives rise to a band gap opening at the Fermi level, and thus, semiconducting behavior. On the other hand, in salt 2, two crystallographically independent coronene molecules (A and B) form π-stacking columns with an AABB repeating unit, which are flanked by another coronene molecule (C). The crystallographic features, such as interplanar distances and in-plane molecular distortions arising from the Jahn-Teller effect, as well as the first-principle calculations, strongly suggested the emergence of charge disproportionation within the π-columns.
To fully utilize the great potential of graphene in electronics, a comprehensive understanding of the electronic properties of finite-size graphene flakes is essential. While the coronene series with n fused benzene rings at each side (designated as n-coronenes) are possible structures for opening a band gap in graphene, their electronic properties are not yet fully understood. Nevertheless, because of their radical character, it remains very difficult to reliably predict the electronic properties of the larger n-coronenes with conventional computational approaches. In order to circumvent this, the various electronic properties of n-coronenes (n ¼ 2-11) are investigated using thermally-assisted-occupation density functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys., 2012, 136, 154104], a very efficient electronic structure method for studying nanoscale systems with strong static correlation effects. The ground states of the larger n-coronenes are shown to be polyradical singlets, where the active orbitals are mainly localized at the zigzag edges.
Arylthio-substituted coronenes as tailored building blocks for molecular electronics
Physical Chemistry Chemical Physics, 2012
The electron transport through molecules in molecular devices is typically influenced by the nature of the interfaces with the contacting electrodes and by the interactions between neighbouring molecules. It is a major goal of molecular electronics to adjust the electronic function of a molecular device by tailoring the intrinsic molecular properties and the interfacial and intermolecular interactions. Here, we report on the tunability of the electronic properties of coronene derivatives, namely dodecakis(arylthio)coronenes (DATCs), which are found to exhibit a three-dimensional aromatic system. Scanning tunnelling microscopy (STM), spectroscopy (STS) and simulations based on the density functional theory (DFT) are employed to characterize the structural and electronic properties of these molecules deposited on Au(111) surfaces. It is shown that modifications of the peripheral aryl-groups allow us to specifically affect the self-assembly and the charge transport characteristics of the molecules. Molecular assemblies like supramolecular wires with highly delocalized orbitals and single molecules with molecular ''quantum dot'' characteristics are obtained in this way.
Structure and Transport Properties of the Charge-Transfer Salt Coronene−TCNQ
Chemistry of Materials
Coronene is a highly symmetric organic molecule whose molecular structure resembles a fragment of graphite. We have crystallized a charge-transfer complex based on coronene and TCNQ, and present crystal structure and transport properties. The complex adopts alternate stacking between coronene and TCNQ, and the charge-transfer was estimated to be of the order of 0.3 by the structure and IR analysis of TCNQ. This degree of chargetransfer is larger than those of other hydrocarbon based charge-transfer complexes reported. We find semiconductor behavior with an optical gap of 1.55 eV and a transport gap of 0.49 eV. The Child's law mobility is estimated to be 0.3 cm 2 /Vssthis along with the small transport gap suggests this compound might be attractive for device applications.
The Journal of Physical Chemistry C, 2012
We investigate the energetics, electronic structure, optical properties, and charge transfer characteristics of coronene and its imide-functionalized derivatives using quantum chemical calculations. We analyze the formation feasibility of pristine coronene and its different imide monomers, namely, coronene-5-diimide, coronene-6-diimide, and coronene-tetraimide, from a common parental compound, coronene octacarboxylic acid, and find that the most favorable derivative is the pure coronene. Our results also show that coronene-6-diimide is preferred over other possible imide compounds, which is well in accordance with the relative experimental abundance of coronene-6-diimide. The absorption characteristics obtained for both the monomer and dimer of coronene imides show bathochromic shifts for the low-energy peak positions in comparison to the pristine coronene because of the presence of the electron withdrawing imide groups, and the trend in transition energy follows the order of the electronic gap. Interestingly, we find a larger extent of red shift for the absorption maxima of the synthetically more feasible coronene-6-diimide among others. Moreover, our analysis also shows that the extent of red shift strongly depends on the position and orientations of the imide groups, and the low-energy peaks solely correspond to the π–π* electronic transitions. Furthermore, we also calculate the charge (electron and hole) transfer integrals for the plausible stable dimers, and find that effective hole transfer integrals are significantly larger than the electron transfer integral except for the coronene-tetraimide, for which the electron transfer integral is found to be greater than the hole transfer integral. The calculated carrier mobilities for the coronene crystal show that the hole mobility is significantly larger, almost 15 times, than the electron mobility. Our study provides a detailed understanding of the tunable optical and charge transfer properties for imide-functionalized coronene derivatives, and suggests their potential use in optoelectronic and field effect transistor devices.
2021
We have investigated the structures, electronic properties, hole and electron mobilities of perfluorinated, perchlorinated and percyanated coronene molecules, using the density functional theory (DFT) at the B3LYP-D3/6-311++G(d,p) and ωB97XD/6-311++G(d,p) levels and Markus-Hush charge transfer theory. The calculated geometric parameters for coronene and perchlorocoronene are in good agreement with the experimental data. Our theoretical investigations have shown B3LYP-D3 functional is suitable to well define vibrational assignments for studied molecules. We have shown that the per-halogenation and per-cyanation of coronene increases the adiabatic electron affinities (AEAs) and reduces the LUMO levels and the hole mobilities thus indicating an ambipolar behavior and air-stable material. We have shown that the percyanation of coronene is a promising pathway for the design of new materials useful in optoelectronics.
Correlated Study of Linear Optical Absorption in Lower Symmetry Coronene Derivatives
arXiv: Chemical Physics, 2020
The electronic and optical properties of four different coronene derivatives with lower symmetry, namely, benzo[a]coronene (C$_{28}$H$_{14}$), naphtho[2,3a]coronene (C$_{32}$H$_{16}$), anthra[2,3a]coronene (C$_{36}$H$_{18}$) and naphtho[8,1,2abc]coronene (C$_{30}$H$_{14}$) were investigated. For the purpose, we performed electron-correlated calculations using screened and standard parameters in the pi\pipi-electron Pariser-Parr-Pople (PPP) Hamiltonian, and the correlation effects were included, both for ground and excited states, using MRSDCI methodology. The PPP model Hamiltonian includes long range Coulomb interactions which increases the accuracy of our calculations. The results of our calculations predict that with the increasing sizes of the coronene derivatives, optical spectra are red shifted as well as the optical gaps decrease. In each spectrum, the first peak represents the optical gap which is moderately intense, while the more intense peaks appear at higher energies. Our c...
Optical and Quantum Electronics, 2017
In this work we have investigated the effects of substituting carbon atoms with B, N and BN on the electronic structure, physico-chemical, linear and non linear optical properties of Coronene (C24H12) using HF and DFT methods. We have calculated total electronic energy E 0 , zero point vibrational energy ZPVE, the enthalpy H, entropy S, molar heat capacity at constant volume C v , ionization potential IP, electron affinity EA, hardness j, softness #, electronegativity EN, dipole moment l, average polarizability \a [ , anisotropy Da, the first molecular hyperpolarizability b mol , second order hyperpolarizability c av , HOMO-LUMO Energy gap E gap , work function E F , refractive index n, susceptibility v, dielectric constant e and molar refractivity MR of coronene (C24H12), the 6B-, 6N-and 3B3N-substitute-doped C24H12 C18B6H12 C18N6H12 and C18B3N3H12. The E gap values of the molecules are between 0.91 and 2.36 eV. We observed that b mol changes slightly when C24H12 is doped with either 6B or 6N even though their b mol values are too small. However, by doping C24H12 with both 3B and 3N, creating a strong donoracceptor system, a very large increase in l and b mol was found for C18B3N3H12. This study was done using RHF, B3LYP and wB97XD methods with the cc-pVDZ basis set. The studies have shown that doping decreases some of the above properties significantly while some increases significantly compared to pure coronene, suggesting that 6B-, 6N- ,