London Dispersion Effects in a Distannene/Tristannane Equilibrium: Energies of their Interconversion and the Suppression of the Monomeric Stannylene Intermediate.
Angew Chem Int Ed Engl
; 62(22): e202301919, 2023 May 22.
Article
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| ID: mdl-36780498
ABSTRACT
Reaction of {LiC6 H2 -2,4,6-Cyp3 â
Et2 O}2 (Cyp=cyclopentyl) (1) of the new dispersion energy donor (DED) ligand, 2,4,6-triscyclopentylphenyl with SnCl2 afforded a mixture of the distannene {Sn(C6 H2 -2,4,6-Cyp3 )2 }2 (2), and the cyclotristannane {Sn(C6 H2 -2,4,6-Cyp3 )2 }3 (3). 2 is favored in solution at higher temperature (345â
K or above) whereas 3 is preferred near 298â
K. Van't Hoff analysis revealed the 3 to 2 conversion has a ΔH=33.36â
kcal mol-1 and ΔS=0.102â
kcal mol-1 K-1 , which gives a ΔG300 K =+2.86â
kcal mol-1 , showing that the conversion of 3 to 2 is an endergonic process. Computational studies show that DED stabilization in 3 is -28.5â
kcal mol-1 per {Sn(C6 H2 -2,4,6-Cyp3 )2 unit, which exceeds the DED energy in 2 of -16.3â
kcal mol-1 per unit. The data clearly show that dispersion interactions are the main arbiter of the 3 to 2 equilibrium. Both 2 and 3 possess large dispersion stabilization energies which suppress monomer dissociation (supported by EDA results).
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Angew Chem Int Ed Engl
Año:
2023
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Article
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Estados Unidos