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Abstract The industrial importance of the CC double bond difunctionalization in vegetable oils/fatty acid chains motivates computational studies aimed at helping to improve experimental protocols. The CC double bond epoxidation is studied with hydrogen peroxide, peracetic acid (CH3CO3H), and performic acid (HCO3H) oxidizing agents. The epoxide ring‐opening mechanism is calculated in the presence of ZnCl2, NiCl2, and FeCl2Lewis acidic catalysts. Computations show that H2O2(∆G‡= 39 kcal/mol,TS1HP) is not an effective oxidizing agent compared to CH3CO3H (∆G‡= 29.8 kcal/mol,TS1PA) and HCO3H (∆G‡= 26.7 kcal/mol,TS1PF). The FeCl2(∆G‡= 14.7 kcal/mol,TS1FC) coordination to the epoxide oxygen facilitates the ring‐opening via lower energy barriers compared to the ZnCl2(∆G‡= 19.5 kcal/mol,TS1ZC) and NiCl2(∆G‡= 29.4 kcal/mol,TS1NC) coordination. ZnCl2was frequently utilized as a catalyst in laboratory‐scale procedures. The energetic span model identifies the FeCl2(FC) catalytic cycle as the best option for the epoxide ring‐opening.
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This content will become publicly available on July 31, 2026
Exciton Trapping at Shape‐Persistent Molecular Nanotubes
Abstract We report a series of shape‐persistent molecular nanotubes with top rim connectivity traversing from an all‐meta‐ (m4) to an all‐para‐phenylene (p4) bridged species, including all possible members in between them. Single‐crystal X‐ray diffraction (SCXRD) and microcrystal electron diffraction (MicroED) data show a large torsional angle formeta‐phenylenes relative topara‐phenylene rings. Density functional theory (DFT) calculations reproduce the experimental torsional angles and also establish a correlation indicating a gradual increase in strain energy fromm4(∼31 kcal mol−1) top4(∼90 kcal mol−1). Structural transitions fromm4top4lead to additional correlations such as a shift in the lowest absorption wavelength from 330 to 394 nm, a sizeable red shift in the maximum emission wavelength from 444 to 546 nm, and a decrease in fluorescence quantum yield from 0.76 to 0.20, respectively. Time‐dependent (TD)‐DFT analysis of the relaxed excited state (S1’) geometry shows a progression of exciton delocalization aspara‐phenylenes are introduced intom4en route top4, while the overall molecular size remains constant. This effect is directly related to increased π‐conjugation within the nanotube's top‐segment and demonstrates how exciton trapping can take place without changing the nanotube's physical size, e.g., diameter and length.
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- Award ID(s):
- 2302628
- PAR ID:
- 10621657
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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