Propella[34] prismane and its congeners: A MO‐theoretical study

Gleiter, Rolf; Pfeifer, Karl‐Heinz; Koch, Wolfram

doi:10.1002/jcc.540160104

Cited by 7 publications

(11 citation statements)

References 34 publications

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“…16 Gleiter also demonstrated that one could achieve the [2+2]photocycloaddition of 1 by shortening the intramolecular π-π distance (Δr = 0.3 Å) with tethered propyl bridges (-CH2CH2CH2-), which lowers the πSS to HOMO-1, thus restoring the requisite orbital-symmetry to allow the [2+2]-photocycloaddition. 15 5), 17 octa(trifluoromethyl)cubane (8), 18 and octacyclopropylcubane (11). 19 The correlation diagrams for the [2+2]-cycloadditions of substituted [3]-ladderenes (i.e., 4, 7, and 10) are qualitatively similar and suggest that this pathway is symmetry-forbidden.…”

Section: Introductionmentioning

confidence: 95%

Machine-learning photodynamics simulations uncover the role of substituent effects on the photochemical formation of cubanes

Stein

Adrion

et al. 2021

Preprint

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Photochemical [2+2]-photocycloadditions are used to efficiently access strained organic molecular architectures, storing solar energy in chemical bonds. Functionalized [3]-ladderenes have been shown to undergo [2+2]-photocycloadditions to afford cubanes, an energy-dense class of organic molecules. The substituents (e.g., methyl, trifluoromethyl, and cyclopropyl) affect the overall reactivities of these cubane precursors leading to a yield from 1% to 48%. We now integrate single and multireference calculations and our machine-learning-accelerated nonadiabatic molecular dynamics (ML-NAMD) to understand how substituents affect the mechanistic photodynamics of [2+2]-photocycloadditions. Our calculations show that steric clashes destabilize the 4π-electrocyclic ring-opening pathway and minimum energy conical intersections by 0.72-1.15 eV and reaction energies by 0.68-2.34 eV. In contrast, favorable dispersive interactions stabilize the [2+2]-photocycloaddition pathway, lower the conical intersection energies by 0.31-0.85 eV and cubane reaction energies by 0.03-0.82 eV. The 2 ps ML-NAMD trajectories reveal that closed-shell repulsions block a 6π-conrotatory electrocyclic ring-opening pathway with increasing steric bulk. 57% of the methyl-substituted [3]-ladderene trajectories proceed through the 6π-conrotatory electrocyclic ring-opening, whereas the trifluoromethyl-and cyclopropylsubstituted 3-ladderenes chemoselectively proceed through [2+2]-photocycloaddition pathways. The predicted cubane yields (H: 0.4% < CH3: 1% < CF3: 14% < cPr: 20%) match the experimental trend; these substituents pre-distort the reactants to resemble the conical intersection leading to cubane.

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Section: Introductionmentioning

confidence: 95%

Machine-learning photodynamics simulations uncover the role of substituent effects on the photochemical formation of cubanes

Stein

Adrion

et al. 2021

Preprint

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“…The [2 + 2] photocycloaddition of unsubstituted tricyclo[4,2,0,0 2,5 ]octa-3,7-dienes ( 1 ) has not been experimentally reported. Gleiter and co-workers found the [2 + 2] photocycloaddition via the lowest-energy photoexcitation of 1 is symmetry forbidden using then-contemporary methods such as AM1 and Hartree–Fock with the 3-21G basis set. Through-space orbital interactions between the π- and σ-orbitals of the tricyclic framework were shown to rearrange the frontier molecular orbitals (FMOs) as shown in Scheme . , Gleiter explains that the lowest-energy transition in the TOD precursor of propellacubane (Scheme ) is symmetry-allowed because the reduced through-bond interactions lead to rearranged FMOs and an observed [2 + 2] photocycloaddition. ,, …”

Section: Introductionmentioning

confidence: 99%

“…22 The [2 + 2] photocycloaddition of unsubstituted tricyclo-[4,2,0,0 2,5 ]octa-3,7-dienes (1) has not been experimentally reported. Gleiter and co-workers found the [2 + 2] photocycloaddition via the lowest-energy photoexcitation of 1 is symmetry forbidden 23 using then-contemporary methods such as AM1 24 and Hartree−Fock with the 3-21G basis set. Through-space orbital interactions between the πand σorbitals of the tricyclic framework were shown to rearrange the frontier molecular orbitals (FMOs) as shown in Scheme 2.…”

Section: ■ Introductionmentioning

confidence: 99%

Multiconfigurational Calculations and Nonadiabatic Molecular Dynamics Explain Tricyclooctadiene Photochemical Chemoselectivity

Lopez

2020

J. Phys. Chem. A

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Sunlight is a renewable energy source that can be stored in chemical bonds using photochemical reactions. The synthesis of exotic and strained molecules is especially attractive with photochemical techniques because of the associated efficient and mild reaction conditions. We have understood the photophysics and subsequent photochemistry of a possible cubane precursor, tricyclo[4,2,0,0 2,5 ]octa-3,7-diene with complete active space self-consistent field (CASSCF) calculations with an (8,7) active space and the ANO-S-VDZP basis set to. The CASSCF energies were corrected with a second-order perturbative correction CASPT2(8,7)/ANO-S-VDZP. The S 0 → S 1 vertical excitation energy of 1 is 6.25 eV, which is a π → π* excitation. The minimum energy path from the S 1 Franck−Condon point leads to a 4π-disrotatory electrocyclic ring-opening reaction to afford bicyclo[4,2,0]octa-2,4,7-triene. The 2D potential energy surface scan located a rhomboidal S 1 /S 0 minimum energy crossing point connecting 1 and cubane, suggesting that a cycloaddition is theoretically possible. We used the fewest switches surface hopping to study the photodynamics of this cycloaddition: 85% of 1722 trajectories relaxed to eight products; the major products are bicyclo[4,2,0]octa-2,4,7-triene (30%) and cycloocta-1,3,5,7-tetraene (32%). Only 0.4% of trajectories undergo a [2 + 2] cycloaddition to form cubane.

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“…Through-space orbital interactions between the π-and σ-orbitals of the tricyclic framework were shown to rearrange the frontier molecular orbitals (FMOs) as shown in Scheme 2. 16 Gleiter explains that the lowest-energy transition in the TOD precursor of propellacubane (Scheme 1) is symmetry-allowed because the reduced through-bond interactions lead to rearranged FMOs and an observed [2+2] photocycloaddition. 16,18 Scheme 2.…”

Section: Introductionmentioning

confidence: 99%

“…16 Gleiter explains that the lowest-energy transition in the TOD precursor of propellacubane (Scheme 1) is symmetry-allowed because the reduced through-bond interactions lead to rearranged FMOs and an observed [2+2] photocycloaddition. 16,18 Scheme 2. Frontier molecular orbitals diagram of 1.…”

Section: Introductionmentioning

confidence: 99%

Multiconfigurational Static and Dynamic Calculations Explain Tricyclo[4,2,0,02,5]octa-3,7-diene Photochemistry

Li¹,

Lopez

2020

Preprint

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Sunlight is a renewable energy source that can be stored in chemical bonds using photochemical reactions. The synthesis of exotic and strained molecules is especially attractive with photochemical techniques because of the associated efficient and mild reaction conditions. We have used complete active space self-consistent field (CASSCF) calculations with an (8,7) active space and the ANO-S-VDZP basis set to understand the photophysics and subsequent photochemistry of a possible cubane precursor tricyclo[4,2,0,02,5]octa-3,7-diene (1). The energies were corrected with a second-order perturbative correction CASPT2(8,7)/ANO-S-VDZP. The S0→S1 vertical excitation energy of 1 is 6.25 eV, whose nature is π→π* excitation. The minimum energy path from the S1 Franck-Condon point leads directly to a 4π-disrotatory electrocyclic ring-opening reaction to afford bicyclo[4,2,0]octa-2,4,7-triene. The 2D potential energy surface scan located a rhomboidal S1/S0 minimum energy crossing point that connects 1 and cubane, suggesting that a cycloaddition is theoretically possible. We used the fewest switches surface hopping to study this reaction: 85% of 1,722 trajectories relaxed to 8 products; the major products are bicyclo[4,2,0]octa-2,4,7-triene (30%) and cycloocta-1,3,5,7-tetraene (32%). Only 0.4% of trajectories undergo a [2+2] cycloaddition to form cubane.

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Propella[3₄] prismane and its congeners: A MO‐theoretical study

Cited by 7 publications

References 34 publications

Machine-learning photodynamics simulations uncover the role of substituent effects on the photochemical formation of cubanes

Machine-learning photodynamics simulations uncover the role of substituent effects on the photochemical formation of cubanes

Multiconfigurational Calculations and Nonadiabatic Molecular Dynamics Explain Tricyclooctadiene Photochemical Chemoselectivity

Multiconfigurational Static and Dynamic Calculations Explain Tricyclo[4,2,0,02,5]octa-3,7-diene Photochemistry

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