Theoretical Study on the Molecular Distortions in [2.2]Paracyclophane and Cyclobutane

Henseler, Debora; Hohlneicher, Georg

doi:10.1021/jp983013w

Cited by 47 publications

(53 citation statements)

References 39 publications

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“…At the DFT-B3LYP/ TZV(2df,2p) level, a minimum with D 2h symmetry is obtained that also prevails with larger AO basis sets. Previous B3LYP/4±31G(d) calculations of Walden and Glatzhofer, [43] which gave a slightly twisted geometry (f= 3.98), seem to suffer from basis set incompleteness and are thus not decisive. The MP2/6±31G(d) calculations performed in 1998 by Henseler and Hohlneicher [44] gave f= 21.88, which is in reasonable agreement with the MP2 data reported here.…”

Section: Methodsmentioning

confidence: 94%

On the Importance of Electron Correlation Effects for the π‐π Interactions in Cyclophanes

Grimme

2004

Chemistry A European J

167

206

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Correlated ab initio quantum chemical methods based on second-order perturbation theory and density functional theory (DFT) together with large atomic orbital (AO) basis sets are used to calculate the structures of four cyclophanes with two aromatic rings and one sulphur-containing phane with one aromatic ring. The calculated geometrical data for [2.2]paracyclophane, cyclophane (superphane), 8,16-dimethyl[2.2]metacyclophane, 16-methyl[2.2]metaparacyclophane, and 2,6,15-trithia[3(4,10)][7]metacyclophane are compared to experimental data from X-ray crystal structure determinations. In all cases, very accurate theoretical predictions are obtained from the recently developed spin-component-scaled MP2 (SCS-MP2) method, in which the deviations are within the experimental accuracy and expected crystal-packing or vibrational effects. Especially the inter-ring distances, which are determined by a detailed balance between attractive van der Waals (dispersive) and repulsive (Pauli) contributions, are very sensitive to the level of theory employed. While standard MP2 theory in general overestimates the dispersive interactions (pi-pi correlations) between the two aromatic rings leading to too short distances (between 3 and 8 pm), the opposite is observed for DFT methods (errors up to 15 pm). This indicates that an explicit account of dispersive-type electron correlation effects between the clamped aromatic units is essential for a quantitative description of cyclophane structures. In order to distinguish these effects from "normal" van der Waals interactions, the term "overlap-dispersive" interaction may be employed. The popular B3 LYP hybrid density functional offers no advantage over the pure PBE functional that at least qualitatively accounts for some of the dispersive effects. The use of properly polarized AO basis sets of at least valence-triple-zeta quality is strongly recommended to obtain quantitative predictions with traditional wave function methods.

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Section: Methodsmentioning

confidence: 94%

On the Importance of Electron Correlation Effects for the π‐π Interactions in Cyclophanes

Grimme

2004

Chemistry A European J

167

206

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“…This distortion was also observed in previous computational and experimental studies of [2.2]paracyclophane. [35][36][37] An important point to notice is that the vinyl groups are twisted by 268 out of the plane of the phenyl rings. The twist angles in the syn-anti conformer (not shown) are similar.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

Pseudo‐Bimolecular [2+2] Cycloaddition Studied by Time‐Resolved Photoelectron Spectroscopy

Brogaard

Boguslavskiy

Schalk

et al. 2011

Chemistry A European J

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The first study of pseudo‐bimolecular cycloaddition reaction dynamics in the gas phase is presented. We used femtosecond time‐resolved photoelectron spectroscopy (TRPES) to study the [2+2] photocycloaddition in the model system pseudo‐gem‐divinyl[2.2]paracyclophane. From X‐ray crystal diffraction measurements we found that the ground‐state molecule can exist in two conformers; a reactive one in which the vinyl groups are immediately situated for [2+2] cycloaddition and a nonreactive conformer in which they point in opposite directions. From the measured S1 lifetimes we assigned a clear relation between the conformation and the excited‐state reactivity; the reactive conformer has a lifetime of 13 ps, populating the ground state through a conical intersection leading to [2+2] cycloaddition, whereas the nonreactive conformer has a lifetime of 400 ps. Ab initio calculations were performed to locate the relevant conical intersection (CI) and calculate an excited‐state [2+2] cycloaddition reaction path. The interpretation of the results is supported by experimental results on the similar but nonreactive pseudo‐para‐divinyl[2.2]paracyclophane, which has a lifetime of more than 500 ps in the S1 state.

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“…All DFT calculations were carried out with the 6-31G** split valence plus polarization basis set [89,90,91,92,93]. According to other reports, this method may provide reasonable cyclophane structures compared with X-ray data [94] and other ab-initio results [95]. The excitation energies and electronic structures were calculated by the single configuration-interaction (SCI) [60] scheme with all occupied and unoccupied π-levels included within the semiempirical intermediate neglect of differential overlap (INDO) model [79], as parameterized by Zerner and co-workers [80].…”

Section: Theoretical Modelsmentioning

confidence: 99%

Charge-Transfer Interactions in Organic Functional Materials

Lin

Jin

2010

Materials

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Our goal in this review is three-fold. First, we provide an overview of a number of quantum-chemical methods that can abstract charge-transfer (CT) information on the excited-state species of organic conjugated materials, which can then be exploited for the understanding and design of organic photodiodes and solar cells at the molecular level. We stress that the Composite-Molecule (CM) model is useful for evaluating the electronic excited states and excitonic couplings of the organic molecules in the solid state. We start from a simple polyene dimer as an example to illustrate how interchain separation and chain size affect the intercahin interaction and the role of the charge transfer interaction in the excited state of the polyene dimers. With the basic knowledge from analysis of the polyene system, we then study more practical organic materials such as oligophenylenevinylenes (OPVn), oligothiophenes (OTn), and oligophenylenes (OPn). Finally, we apply this method to address the delocalization pathway (through-bond and/or through-space) in the lowest excited state for cyclophanes by combining the charge-transfer contributions calculated on the cyclophanes and the corresponding hypothetical molecules with tethers removed. This review represents a step forward in the understanding of the nature of the charge-transfer interactions in the excited state of organic functional materials.

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Theoretical Study on the Molecular Distortions in [2.2]Paracyclophane and Cyclobutane

Cited by 47 publications

References 39 publications

On the Importance of Electron Correlation Effects for the π‐π Interactions in Cyclophanes

On the Importance of Electron Correlation Effects for the π‐π Interactions in Cyclophanes

Pseudo‐Bimolecular [2+2] Cycloaddition Studied by Time‐Resolved Photoelectron Spectroscopy

Charge-Transfer Interactions in Organic Functional Materials

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