S–H Bond Activation in Hydrogen Sulfide by NHC-Stabilized Silyliumylidene Ions
AbstractReactivity studies of silyliumylidenes remain scarce with only a handful of publications to date. Herein we report the activation of S–H bonds in hydrogen sulfide by mTer-silyliumylidene ion A (mTer = 2,6-Mes2-C6H3, Mes = 2,4,6-Me3-C6H2) to yield an NHC-stabilized thiosilaaldehyde B. The results of NBO and QTAIM analyses suggest a zwitterionic formulation of the product B as the most appropriate. Detailed mechanistic investigations are performed at the M06-L/6-311+G(d,p)(SMD: acetonitrile/benzene)//M06-L/6-311+G(d,p) level of density functional theory. Several pathways for the formation of thiosilaaldehyde B are examined. The energetically preferred route commences with a stepwise addition of H2S to the nucleophilic silicon center. Subsequent NHC dissociation and proton abstraction yields the thiosilaaldehyde in a strongly exergonic reaction. Intermediacy of a chlorosilylene or a thiosilylene is kinetically precluded. With an overall activation barrier of 15 kcal/mol, the resulting mechanistic picture is fully in line with the experimental observation of an instantaneous reaction at sub-zero temperatures. View Full-Text
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Porzelt, A.; Schweizer, J.I.; Baierl, R.; Altmann, P.J.; Holthausen, M.C.; Inoue, S. S–H Bond Activation in Hydrogen Sulfide by NHC-Stabilized Silyliumylidene Ions. Inorganics 2018, 6, 54.
Porzelt A, Schweizer JI, Baierl R, Altmann PJ, Holthausen MC, Inoue S. S–H Bond Activation in Hydrogen Sulfide by NHC-Stabilized Silyliumylidene Ions. Inorganics. 2018; 6(2):54.Chicago/Turabian Style
Porzelt, Amelie; Schweizer, Julia I.; Baierl, Ramona; Altmann, Philipp J.; Holthausen, Max C.; Inoue, Shigeyoshi. 2018. "S–H Bond Activation in Hydrogen Sulfide by NHC-Stabilized Silyliumylidene Ions." Inorganics 6, no. 2: 54.
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