The isomers of phenalene and their singlet and triplet states: A Hartree–Fock and density functional computational investigation

Zoellner, Joan M.; Zoellner, Robert W.

doi:10.1016/j.theochem.2008.05.017

Cited by 10 publications

(6 citation statements)

References 29 publications

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“…Moreover the 14 π-electron count in A obeys the Huckel 4 n + 2 rule for aromaticity. There are no neutral hydrocarbons that are isoelectronic with A , but pyrene ( B ) is related.…”

Section: Resultsmentioning

confidence: 99%

Mono-, Di-, and Triborylphosphine Analogues of Triarylphosphines

2014

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Diazaborinylphosphines based on the 1,8-diaminonaphthylboronamide heterocycle are prepared by a chlorosilane-elimination reaction, and their structural and bonding properties are compared to those of PPh3. The precursor chloroborane ClB{1,8-(NH)2C10H6} (I) is fully characterized including its crystal structure, which features intermolecular π-π stacking, B···N interactions, and N-H···Cl hydrogen bonding. Treatment of I with Ph3-nP(SiMe3)n gave the corresponding Ph3-nP(B{1,8-(NH)2C10H6})n, {L1 (n = 1), L2 (n = 2), and L3 (n = 3)}. The crystal structures of L1-3 reveal an increase in the planarity at P as a function of n, and the steric bulk of the diazaborinyl substituent B{1,8-(NH)2C10H6} is similar to that of a phenyl. Nucleus-independent chemical shift calculations were carried out that suggest that the 14 π-electron diazaborinyl substituent can be described as aromatic overall, though the BN2-containing ring is slightly antiaromatic. The complexes cis-[Mo(L1-3)2(CO)4] (1-3) are prepared from [Mo(nbd)(CO)4] (nbd = norbornadiene) and L1-3. From the position of the ν(CO) (A1) band in the IR spectra of 1-3, it is deduced that the diazaborinyl substituent has a donating capacity similar to an alkyl group.

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“…Moreover the 14 π-electron count in A obeys the Huckel 4 n + 2 rule for aromaticity. There are no neutral hydrocarbons that are isoelectronic with A , but pyrene ( B ) is related.…”

Section: Resultsmentioning

confidence: 99%

Mono-, Di-, and Triborylphosphine Analogues of Triarylphosphines

2014

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“…Depending on the H-position, four possible isomers were investigated, among which only the 1H-phenalene was synthesized so far . B3LYP calculations indicate that 1H-phenalene in the singlet state is the most stable, while the existence of 2 H -phenalene in the triplet state is also suggested . The observed barrierless H-addition to I and a small barrier penetrable by tunneling for H-abstraction, together with exceptionally weak C–H bond at the CH 2 moiety (260 kJ/mol as compared to 373 kJ/mol for analogous bonds in toluene), make the phenalenyl-based systems promising candidates for H-storage.…”

Section: Introductionmentioning

confidence: 99%

“…46,47 These studies also include hydrogenation of I, leading to the formation of phenalene systems. 48−50 Depending on the H-position, four possible isomers were investigated, 49 among which only the 1H-phenalene was synthesized so far. 51 B3LYP calculations indicate that 1Hphenalene in the singlet state is the most stable, while the existence of 2H-phenalene in the triplet state is also suggested.…”

Section: Introductionmentioning

confidence: 99%

“…51 B3LYP calculations indicate that 1Hphenalene in the singlet state is the most stable, while the existence of 2H-phenalene in the triplet state is also suggested. 49 The observed barrierless H-addition to I and a small barrier penetrable by tunneling for H-abstraction, 48 together with exceptionally weak C−H bond at the CH 2 moiety (260 kJ/mol as compared to 373 kJ/mol for analogous bonds in toluene 11 ), make the phenalenyl-based systems promising candidates for H-storage. Hydrogenation of II can form 11 isomers, characterized by either a closed-shell or radical electronic structure.…”

Section: Introductionmentioning

confidence: 99%

“…The hydrogenation of open-shell PAH radicals has emerged as a promising avenue for modifying their electronic and magnetic properties. − Interestingly, these systems have been proposed as potential catalysts for hydrogenation reaction to form H 2 . , These studies also include hydrogenation of I , leading to the formation of phenalene systems. − …”

Section: Introductionmentioning

confidence: 99%

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Stability and Reactivity of the Phenalene and Olympicene Isomers

Ferrão,

Pontes,

Fernandes

et al. 2023

J. Phys. Chem. A

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The phenalene (triangulene) and olympicene molecules belong to the polycyclic aromatic hydrocarbon class, which have attracted substantial technological interest due to their unique electronic properties. Electronic structure calculations serve as a valuable tool in investigating the stability and reactivity of these molecular systems. In the present work, the multireference calculations, namely, the complete active space second-order perturbation theory and multireference averaged quadratic coupled cluster (MR-AQCC), were employed to study the reactivity and stability of phenalene and olympicene isomers, as well as their modified structures where the sp 3 -carbon at the borders were removed. The harmonic oscillator model of aromaticity (HOMA) and the nucleus-independent chemical shift as geometric and magnetic indexes calculated with density functional theory were utilized to assess the aromaticity of the studied molecules. These indexes were compared with properties such as the excitation energy and natural orbitals occupation. The reactivity analyzed using the HOMA index combined with MR-AQCC revealed the radical character of certain structures as well as the weakening of their aromaticity. Moreover, the results suggest that the removal of sp 3 -carbon atoms and the addition of hydrogen atoms did not alter the π network and the excitation energies of the phenalene molecules.

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Theoretical Design of High‐Spin Polycyclic Hydrocarbons

Trinquier¹,

Suaud²,

Malrieu³

2010

Chemistry A European J

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High-spin organic structures can be obtained from fused polycyclic hydrocarbons, by converting selected peripheral HC(sp(2)) sites into H(2)C(sp(3)) ones, guided by Ovchinnikov's rule. Theoretical investigation is performed on a few examples of such systems, involving three to twelve fused rings, and maintaining threefold symmetry. Unrestricted DFT (UDFT) calculations, including geometry optimizations, confirm the high-spin multiplicity of the ground state. Spin-density distributions and low-energy spectra are further studied through geometry-dependent Heisenberg-Hamiltonian diagonalizations and explicit correlated ab initio treatments, which all agree on the high-spin character of the suggested structures, and locate the low-lying states at significantly higher energies. In particular, the lowest-lying state of lower multiplicity is always found to be higher than kT at room temperature (at least ten times higher). Simplification of the ferromagnetic organization based on sets of semilocalized nonbonding orbitals is proposed. Molecular architectures are thus conceived in which the ferromagnetically-coupled unpaired electrons tally up to one third of the involved conjugated carbons. Connecting such building blocks should provide bidimensional materials endowed with robust magnetic properties.

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The isomers of phenalene and their singlet and triplet states: A Hartree–Fock and density functional computational investigation

Cited by 10 publications

References 29 publications

Mono-, Di-, and Triborylphosphine Analogues of Triarylphosphines

Mono-, Di-, and Triborylphosphine Analogues of Triarylphosphines

Stability and Reactivity of the Phenalene and Olympicene Isomers

Theoretical Design of High‐Spin Polycyclic Hydrocarbons

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