Synthesis of electron-rich metal-substituted silylenes and their potential in small molecule bond activation

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Acyclic silylenes are typically more reactive compared to their cyclic congeners due to their reduced singlet-triplet energy barrier and their promising potential for small molecule activation reactions, i.e. H2, CO or CO2, has been demonstrated in recent years. Even though these studies showed some parallels to the well-known chemistry of transition metal complexes, one of the most central reaction, the formation of metal carbonyl complexes by reaction with CO, is unknown for silylenes. We recently succeeded in the synthesis of the first room temperature-stabile silylene carbonyl complex [L1(Br)Ga]2Si–CO 6 by reaction of the metal substituted silylene [L1(Br)Ga]2Si: with CO. In this research project, we will try to generalize the synthesis of metal-substituted silylenes [L(X)M]2Si: and study the influence of the group 13 diyles LM as well as the starting silicon reagents SiX4 (X = Cl, Br, I, NR2, OR) on the reaction pathway as well as the stability of the resulting silylenes. We will furthermore investigate the potential of the silylene [L1(Br)Ga]2Si: and the carbonyl complex [L1(Br)Ga]2Si–CO 6 as well as of compound 5 in small molecule activation reactions with H2, CO, CO2, olefines C2R4, alkines C2R2, CN multiple bonds and E-H main group element hydrides. In situ NMR spectroscopic studies and computational calculations should provide a mechanistical understanding of the reaction and a detailed understanding of the electronic nature of the resulting complexes.