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Abstract Reaction of {LiC6H2−2,4,6‐Cyp3⋅Et2O}2(Cyp=cyclopentyl) (1) of the new dispersion energy donor (DED) ligand, 2,4,6‐triscyclopentylphenyl with SnCl2afforded a mixture of the distannene {Sn(C6H2−2,4,6‐Cyp3)2}2(2), and the cyclotristannane {Sn(C6H2−2,4,6‐Cyp3)2}3(3).2is favored in solution at higher temperature (345 K or above) whereas3is preferred near 298 K. Van't Hoff analysis revealed the3to2conversion has a ΔH=33.36 kcal mol−1and ΔS=0.102 kcal mol−1 K−1, which gives a ΔG300 K=+2.86 kcal mol−1, showing that the conversion of3to2is an endergonic process. Computational studies show that DED stabilization in3is −28.5 kcal mol−1per {Sn(C6H2−2,4,6‐Cyp3)2unit, which exceeds the DED energy in2of −16.3 kcal mol−1per unit. The data clearly show that dispersion interactions are the main arbiter of the3to2equilibrium. Both2and3possess large dispersion stabilization energies which suppress monomer dissociation (supported by EDA results).
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Computational predictions on Brønsted acidic ionic liquid-catalyzed carbon dioxide conversion to five-membered heterocyclic carbonyl derivatives
Experimentally conducted reactions between CO 2 and various substrates ( i.e. , ethylenediamine (EDA), ethanolamine (ETA), ethylene glycol (EG), mercaptoethanol (ME), and ethylene dithiol (EDT)) are considered in a computational study. The reactions were previously conducted under harsh conditions utilizing toxic metal catalysts. We computationally utilize Brønsted acidic ionic liquid (IL) [Et 2 NH 2 ]HSO 4 as a catalyst aiming to investigate and propose ‘greener’ pathways for future experimental studies. Computations show that EDA is the best to fixate CO 2 among the tested substrates: the nucleophilic EDA attack on CO 2 is calculated to have a very small energy barrier to overcome (TS1EDA, Δ G ‡ = 1.4 kcal mol −1 ) and form I1EDA (carbamic acid adduct). The formed intermediate is converted to cyclic urea (PEDA, imidazolidin-2-one) via ring closure and dehydration of the concerted transition state (TS2EDA, Δ G ‡ = 32.8 kcal mol −1 ). Solvation model analysis demonstrates that nonpolar solvents (hexane, THF) are better for fixing CO 2 with EDA. Attaching electron-donating and -withdrawing groups to EDA does not reduce the energy barriers. Modifying the IL via changing the anion part (HSO 4 − ) central S atom with 6 A and 5 A group elements (Se, P, and As) shows that a Se-based IL can be utilized for the same purpose. Molecular dynamics (MD) simulations reveal that the IL ion pairs can hold substrates and CO 2 molecules via noncovalent interactions to ease nucleophilic attack on CO 2 .
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- Award ID(s):
- 2152633
- PAR ID:
- 10412905
- Date Published:
- Journal Name:
- Physical Chemistry Chemical Physics
- Volume:
- 25
- Issue:
- 12
- ISSN:
- 1463-9076
- Page Range / eLocation ID:
- 8624 to 8630
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d2cp05877d
