Synthesis, Structure, and Reactivity of Neutral Hydrogen-Substituted Ruthenium Silylene and Germylene Complexes

Reaction of Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)RuCl (<b>1</b>) with 0.5 equiv of Mg(CH<sub>2</sub>Ph)<sub>2</sub>(THF)<sub>2</sub> afforded the benzyl complex Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)Ru(η<sup>3</sup>-CH<sub>2</sub>Ph) (<b>2</b>). Complex <b>2</b> readily reacted with primary silanes H<sub>3</sub>SiR (R = trip, dmp, Mes<sup>F</sup>; trip = 2,4,6-<sup><i>i</i></sup>Pr<sub>3</sub>-C<sub>6</sub>H<sub>2</sub>, dmp = 2,6-Mes<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>, Mes<sup>F</sup> = 2,4,6-(CF<sub>3</sub>)<sub>3</sub>-C<sub>6</sub>H<sub>2</sub>) to liberate toluene and afford hydrogen-substituted silylene complexes Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)(H)RuSiH(R) [R = trip, <b>3</b>; dmp, <b>4</b>; Mes<sup>F</sup>, <b>5</b>]. Complexes <b>3</b>−<b>5</b> exhibit characteristic SiH <sup>1</sup>H NMR resonances downfield of 8 ppm and very small <sup>2</sup><i>J</i><sub>SiH</sub> coupling constants (8−10 Hz). The solid state structures of complexes <b>3</b> and <b>5</b> feature short Ru−Si distances of 2.205(1) and 2.1806(9) Å, respectively, and planar silicon centers. In addition, the silylene complex Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)(H)RuSiPh(trip) (<b>6</b>) and the unusual, chlorine-substituted species Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)(H)RuSiCl(R) [R = trip, <b>7</b>; dmp, <b>8</b>] were prepared. Hydrogen-substituted ruthenium germylene complex Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)(H)RuGeH(trip) (<b>9</b>) was prepared similarly by reaction of <b>2</b> with tripGeH<sub>3</sub>. Complex <b>9</b> is the first structurally characterized ruthernium germylene complex and has a remarkably short Ru−Ge distance of 2.2821(6) Å. Complex <b>9</b> adds H<sub>2</sub>O across its RuGe bond to give Cp*(<sup><i>i</i></sup>Pr<sub>2</sub>MeP)(H)<sub>2</sub>RuGeH(OH)(trip) (<b>10</b>).