Ab initio Hartree—Fock calculations on acetylene dimer

Aoyama, Tomoo; Matsuoka, Osamu; Nakagawa, Naoki

doi:10.1016/0009-2614(79)85215-x

Cited by 41 publications

(22 citation statements)

References 11 publications

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“…For example, it is now well known that the acetylene dimer has a T-shaped structure. [29][30][31][32][33][34][35][36][37][38] All the structures we obtained with various approximate exchange-correlation functionals give a distance between the middle of the C-C bonds which is 1 Å too short. This is a consequence of the bad asymptotic behavior of the exchange-correlation potential which overestimated the weak interactions like those responsible for the bonding in the van der Waals and charge transfer complexes.…”

Section: Resultsmentioning

confidence: 99%

Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Chrétien¹,

Salahub²

2003

The Journal of Chemical Physics

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This is part of a series dealing with the formation of benzene from acetylene on iron clusters, Fenq+ (n=1–4, q=0,1). In this paper, we show that the formation of benzene from acetylene on Fe and Fen+ (n=1–4) is favorable from a thermodynamic point of view. We explain the variation of the rate constants observed for the successive adsorption of acetylene molecules on an iron cation and the experimental observations about the cyclodimerization of acetylene molecules in Fe(C2H2)2+ by referring to the spin conservation principle. Our results indicate that the complexes resulting from the cyclodimerization of Fen(C2H2)2+/Fe(C2H2)2 and Fen(C2H2)3+/Fe(C2H2)3(n=1–4) contain an n-C4H4 ligand (formation of a metallacycle) rather than a cyclobutadiene molecule. However, it is possible to observe the formation of cyclobutadiene from Fe(C2H2)2+ and Fe2(C2H2)3+ only if spin–orbit coupling is significant. A post-self-consistent-field method that includes a multideterminantal treatment is needed to get a quantitative energetic description of the various steps of the reaction. Finally, we discuss various difficulties met in this study and possible ways to deal with them.

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Section: Resultsmentioning

confidence: 99%

Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Chrétien¹,

Salahub²

2003

The Journal of Chemical Physics

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“…A self-assembled charge-transfer complex with an aromatic CH/p interaction [22] is formed, in which the H-bond acceptor (in the "south" unit) is partially positive whereas the Hbond-donor part of the dimer (in the "north" unit) is partially negative ( Figure 3). The weak attractive and charge-transfer nature of the CH/p interaction has been anticipated by theoretical studies for small-sized p systems, [23] benzene, [24] and other aromatics. [25] These weak T-shaped aromatic interactions, however, may significantly control the conformation and molecular-recognition properties of larger molecular systems.…”

Section: Resultsmentioning

confidence: 99%

Edge‐to‐Face CH/π Aromatic Interaction and Molecular Self‐Recognition in epi‐Cinchona‐Based Bifunctional Thiourea Organocatalysis

Tárkányi

Király

Varga

et al. 2008

Chemistry A European J

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The impact of cooperativity between intermolecular interactions is demonstrated by the molecular self-recognition properties of highly enantioselective epi-cinchona bifunctional thiourea organocatalysts. Low-temperature NMR experiments in inert solvents have revealed two sets of nonequivalent resonances in equal population for thiourea-modified members of the epi-quinine and epi-quinidine families. In solution, the predominance of an asymmetric (C1) dimeric self-assembly with noteworthy structural motifs became evident: simultaneous intra- and intermolecular thiourea hydrogen bonding and a CH/pi interaction were observed. Both the stereochemical and the diverse conformational features of the system favor the observed quinoline T-shaped aromatic pi-pi stacking interaction. The structure findings are supported by quantitative proton-proton distance data that were available from NOE buildup curves. The 3D structure of the dimeric assembly has been modeled in agreement with the H-H distance restraints. Owing to the geometrical preference associated with the dimerization process, the self-assembled bifunctional system is interpreted as a charge-transfer complex with the potential for catalyst self-activation.

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“…It is notable that the interaction energy considerably depends on the basis set. Stable conformations of the acetylene dimer were theoretically investigated by Aoyama et al [7]. Its interaction energies of -1.20 and -0.88 kcal/mol were obtained for two different conformations among 64 by their SCF calculations with the 6-3 1 G basis set.…”

Section: Introductionmentioning

confidence: 99%

Ab initio MO Calculations of benzene + TCNE and naphthalene + TCNE complexes with STO‐3G π‐split basis set

Watanabe

Kashiwagi

1983

Int J of Quantum Chemistry

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Ab initio SCF MO calculations have been carried out on benzene +TCNE (tetracyanoethylene) and naphthalene+TCNE complexes with the S T O -~G , sTo-3G nsplit (sT0-3G for D orbitals and a split basis for i~ orbitals), and 4-31G basis sets. The interaction energy, gross charges, dipole moment, and the electron density in the middle plane of the complexes have also been evaluated. The S T O -~G n--split basis set is appropriate for the calculation of large T-T stacking complexes from two points of view, production of reliable results and ease of computations. The approximation scheme based on the semiorthogonalized orgitals is revealed to be very efficient to save CPU time and storage in such calculations. The stable conformation and the charge-transfer interaction of the two complexes are discussed on the basis of the calculated quantities.

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Ab initio Hartree—Fock calculations on acetylene dimer

Cited by 41 publications

References 11 publications

Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Edge‐to‐Face CH/π Aromatic Interaction and Molecular Self‐Recognition in epi‐Cinchona‐Based Bifunctional Thiourea Organocatalysis

Ab initio MO Calculations of benzene + TCNE and naphthalene + TCNE complexes with STO‐3G π‐split basis set

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