Mechanistic investigation of the reactivity of disilene with nitrous oxide: A DFT study

• We performed computational investigation of the reactivity of disilene with N2O.
• Thorough mechanistic study with the possible reaction pathways was evaluated.
• Details of the energetics involved in the three pathways were discussed.
• The silanone containing pathway is the most accessed route for product formation.
• Calculated TDDFT excitations of selected intermediates.

We have reported the mechanistic investigation of the reaction of N2O addition to disilene, trans-[(TMS)2N(η1-Me5C5)SiSi(η1-Me5C5)N(TMS)2] (1t), employing density functional theory (BP86/TZVP//BP86/SVP) calculations. The potential energy surfaces of the title reaction are broadly classified under three pathways. Pathway I deals with the direct N2O additions to 1t affording the trans-dioxadisiletane ring compound Pt whereas in the same pathway we report a different bifurcation route from intermediate 2t. This route portrays the isomerization of trans-monooxadisiletane species 2t prior to the second N2O addition, finally leading to the cis-isomeric product Pc. Different possibilities for isomerization of disilene 1t to 1c were studied in pathway II. The cis-disilene (1c) formed can subsequently react with two N2O molecules affording the cis-product Pc. Pathway III details the formation of silanone type intermediate 6, which subsequently combine with another silanone to afford loosely bound intermediates 7 and 8 respectively. The two separated silanone fragments in the isomeric intermediates 7 and 8 can then dimerizes to furnish the desired products. Among all the calculated potential energy surfaces, pathway III remains the most preferred route for disilene oxygenation under normal experimental condition. The present investigation about disilene reactivity will provide a deeper understanding on silylene chemistry and will exhibit promising applicability in main group chemistry as a whole.

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