A Schrock-Type Germylene Complex: (η⁵‑C₅H₄Et)₂(PMe₃)HfGe(SiMe^tBu₂)₂

The stable group 4 metal germylene complex (η⁵-C₅H₄Et)₂(PMe₃)­HfGe­(SiMe^<i>t</i>Bu₂)₂ (<b>2</b>) is readily available by the reaction of the 1,1-dilithiogermane (^<i>t</i>Bu₂MeSi)₂GeLi₂ with (η⁵-C₅H₄Et)₂HfCl₂ in toluene at −50 °C, followed by treatment with trimethylphosphine. The hafnium–germanium bond distance of 2.6705(5) Å in <b>2</b> is indicative of its double-bond character, being ca. 3–7% shorter than the usual Hf–Ge single bonds. The novel hafnium germylene derivative is classified as a Schrock-type complex, featuring a negatively polarized nucleophilic germanium center

Stibasilene SbSi and Its Lighter Homologues: A Comparative Study

The multiply bonded derivatives of the heavier main group elements are among the most challenging targets for synthetic pursuits. Those of them featuring a double bond between the silicon and group 15 element are represented mostly by the silaimines <i>N</i>Si< and phosphasilenes PSi< with a very few examples of arsasilenes AsSi<. In this contribution, we report on the synthesis and structural elucidation of the first stable stibasilene and novel phosphasilene and arsasilene derivatives, featuring an identical substitution pattern. A systematic comparison within the series phosphasilene–arsasilene–stibasilene is made on the basis of their experimental and computational studies

Stibasilene SbSi and Its Lighter Homologues: A Comparative Study

The multiply bonded derivatives of the heavier main group elements are among the most challenging targets for synthetic pursuits. Those of them featuring a double bond between the silicon and group 15 element are represented mostly by the silaimines <i>N</i>Si< and phosphasilenes PSi< with a very few examples of arsasilenes AsSi<. In this contribution, we report on the synthesis and structural elucidation of the first stable stibasilene and novel phosphasilene and arsasilene derivatives, featuring an identical substitution pattern. A systematic comparison within the series phosphasilene–arsasilene–stibasilene is made on the basis of their experimental and computational studies

Toward a Silicon Version of Metathesis: From Schrock-Type Titanium Silylidenes to Silatitanacyclobutenes

Olefin metathesis is one of the most important industrial processes for the production of alkenes. In contrast, silicon versions of metathesis are unknown given the lack of available silylene transition-metal complexes suitable for [2 + 2] cycloaddition with unsaturated substrates. Here, we report the synthesis of 18-electron titanium silylene complexes featuring different Lewis base ligands and classified on the basis of structural, computational, and reactivity studies as Schrock-type silylene complexes. Because of the presence of loosely bound Lewis base ligands, such silylene complexes readily undergo reaction with simple unsaturated hydrocarbons, such as alkynes, forming the corresponding [2 + 2] cycloaddition products

Toward a Silicon Version of Metathesis: From Schrock-Type Titanium Silylidenes to Silatitanacyclobutenes

Olefin metathesis is one of the most important industrial processes for the production of alkenes. In contrast, silicon versions of metathesis are unknown given the lack of available silylene transition-metal complexes suitable for [2 + 2] cycloaddition with unsaturated substrates. Here, we report the synthesis of 18-electron titanium silylene complexes featuring different Lewis base ligands and classified on the basis of structural, computational, and reactivity studies as Schrock-type silylene complexes. Because of the presence of loosely bound Lewis base ligands, such silylene complexes readily undergo reaction with simple unsaturated hydrocarbons, such as alkynes, forming the corresponding [2 + 2] cycloaddition products