Zou W, Bursch M, Mears KL, Stennett C, Yu P, Fettinger J, Grimme S, Power PP. 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 2023;
62:e202301919. [PMID:
36780498 DOI:
10.1002/anie.202301919]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 02/15/2023]
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 SnCl2 afforded 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). 2 is favored in solution at higher temperature (345 K or above) whereas 3 is preferred near 298 K. Van't Hoff analysis revealed the 3 to 2 conversion has a ΔH = 33.36 kcal mol-1 and ΔS = 0.102 kcal mol-1 K-1, which gives a ΔG300 K = +2.86 kcal mol-1, showing that the conversion of 3 to 2 is an endergonic process. Computational studies show that DED stabilization in 3 is -28.5 kcal mol-1 per {Sn(C6H2-2,4,6-Cyp3)2 unit, which exceeds the DED energy in 2 of -16.3 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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