10.1021/jacs.6b07815.s001 David Nieder David Nieder Volker Huch Volker Huch Cem B. Yildiz Cem B. Yildiz David Scheschkewitz David Scheschkewitz Regiodiscriminating Reactivity of Isolable NHC-Coordinated Disilenyl Germylene and Its Cyclic Isomer American Chemical Society 2016 NHC-coordinated cyclic germylenes 6 b display cyclic 6 b DFT low-valent germanium center Si 5 b cyclopropylidene analogue 6 b NHC i Pr 2 disilenyl germylene 5 b isomerizes Isolable NHC-Coordinated Disilenyl Germylene vinylidene analogue R 2 α- chloro silyl functionalized 2016-09-26 00:00:00 Dataset https://acs.figshare.com/articles/dataset/Regiodiscriminating_Reactivity_of_Isolable_NHC-Coordinated_Disilenyl_Germylene_and_Its_Cyclic_Isomer/4029321 An isolable NHC-coordinated disilenyl germylene R<sub>2</sub>SiSiR-GePh·NHC<sup><i>i</i>Pr<sub>2</sub></sup><sup>Me<sub>2</sub></sup> (<b>5b</b>: R = 2,4,6-triisopropylphenyl, NHC<sup><i>i</i>Pr<sub>2</sub></sup><sup>Me<sub>2</sub></sup> = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) is obtained from the reaction of the α-chloro silyl functionalized heavier vinylidene analogue R<sub>2</sub>(Cl)­Si-RSiGe·NHC<sup><i>i</i>Pr<sub>2</sub></sup><sup>Me<sub>2</sub></sup> with phenyllithium. The disilenyl germylene <b>5b</b> isomerizes at 40 °C to the NHC-adduct of the corresponding heavier cyclopropylidene analogue <b>6b</b>. Both <b>5b</b> and <b>6b</b> display near perfect regiodiscrimination in their reactions with phenylacetylene and xylyl isocyanide, affording in the case of each reagent two different regioisomers of NHC-coordinated cyclic germylenes. DFT calculations reveal that the SiSi bond accounts for the high reactivity of <b>5b</b> even at low temperature while in the case of cyclic <b>6b</b> the low-valent germanium center requires a considerable thermal activation.