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

Group 14 element cationic pentagonal–pyramidal complexes E^a[<i>η</i>⁵-E^b₅(SiMe₃)₅]⁺ (E^a = Si–Pb, E^b = Si, Ge): A quantum-chemical study

<p>Heavy 14 group element cationic half-sandwich complexes E^a[η⁵-E^b₅(SiMe₃)₅]⁺ (E^a = Si–Pb, E^b = Si, Ge) have been studied at the B3LYP/Def2TZVP level of theory. Structures of the neutral complexes {Si[Si₅(SiMe₃)₅]}⁺Cl⁻ and {Si[Si₅(SiMe₃)₅]}⁺[AlCl₄]⁻ are also discussed.</p

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

Spirobis(pentagerma[1.1.1]propellane): A Stable Tetraradicaloid

In this contribution, we report a spirobis­(pentagerma[1.1.1]­propellane) derivative as a novel type of molecular architecture in cluster chemistry that features two spiro-fused [1.1.1]­propellane units and represents a stable tetraradicaloid species. The crucial issue of the nature of the interaction between the germanium bridgeheads was probed computationally, revealing weak bonding interactions between the formally unpaired electrons

Spirobis(pentagerma[1.1.1]propellane): A Stable Tetraradicaloid

In this contribution, we report a spirobis­(pentagerma[1.1.1]­propellane) derivative as a novel type of molecular architecture in cluster chemistry that features two spiro-fused [1.1.1]­propellane units and represents a stable tetraradicaloid species. The crucial issue of the nature of the interaction between the germanium bridgeheads was probed computationally, revealing weak bonding interactions between the formally unpaired electrons

Spirobis(pentagerma[1.1.1]propellane): A Stable Tetraradicaloid

In this contribution, we report a spirobis­(pentagerma[1.1.1]­propellane) derivative as a novel type of molecular architecture in cluster chemistry that features two spiro-fused [1.1.1]­propellane units and represents a stable tetraradicaloid species. The crucial issue of the nature of the interaction between the germanium bridgeheads was probed computationally, revealing weak bonding interactions between the formally unpaired electrons

From Borapyramidane to Borole Dianion

Nonclassical pyramidanes with their inverted tetrahedral configuration of the apical atom are among the most challenging synthetic targets in cluster chemistry. In this Communication, we report on the synthesis and structure of the first representative of pyramidal compounds with the group 13 element at the apex, namely, chloroborapyramidane <b>2</b>. Reduction of <b>2</b> with excess of lithium metal unexpectedly produced the cage-opening product, borole dianion derivative <b>{3</b>^<b>2–</b><b>·[Li­(thf)</b>^<b>+</b><b>]</b>_<b>2</b><b>}</b>, a 6π-electron aromatic system

From Borapyramidane to Borole Dianion

Nonclassical pyramidanes with their inverted tetrahedral configuration of the apical atom are among the most challenging synthetic targets in cluster chemistry. In this Communication, we report on the synthesis and structure of the first representative of pyramidal compounds with the group 13 element at the apex, namely, chloroborapyramidane <b>2</b>. Reduction of <b>2</b> with excess of lithium metal unexpectedly produced the cage-opening product, borole dianion derivative <b>{3</b>^<b>2–</b><b>·[Li­(thf)</b>^<b>+</b><b>]</b>_<b>2</b><b>}</b>, a 6π-electron aromatic system

Pyramidanes

Pyramidane is an elusive but highly desirable target for synthetic chemists that has attracted a great deal of attention because of its nonclassical structure and unusual bonding features. Although well studied on theoretical grounds, neither the parent all-carbon pyramidane nor its derivatives containing heavier group 14 elements have ever been isolated and characterized. In this Communication, we report on the synthesis and structural elucidation of the first stable representatives of this class of highly strained polyhedral compounds: germa- and stannapyramidanes Ge[C₄(SiMe₃)₄] and Sn­[C₄(SiMe₃)₄]. The peculiar structural and bonding features of these compounds are verified by combined experimental and computational analyses, showing these derivatives to be nonclassical neutral compounds with a very large contribution of ionic character