Reactions of GeCl₂ with the Thiolate LiSC(SiMe₃)₃: From thf Activation to Insertion of GeCl₂ Molecules into C−S Bonds

Abstract

The reaction system GeCl2⋅dioxane/LiSTsi (Tsi=C(SiMe3)3) opens a fruitful area in germanium chemistry, depending on the stoichiometry and solvent used during the reaction. For example, the reaction of GeCl2⋅dioxane in toluene with two equivalents of the thiolate gives the expected germylene Ge(STsi)2 in excellent yield. This germylene readily reacts with hydrogen and acetylene, however, in a non‐selective way. By using an excess amount of the thiolate and toluene as the solvent, the germanide [Ge(STsi)3][Li(thf)] is obtained. Performing the same reaction in thf leads to a C−H activation of thf to give (H7C4O)Ge[STsi](μ2‐S)2Ge[STsi]2, in which the thf molecule is still intact. Using a sub‐stoichiometric amount of the thiolate leads to the heteroleptic compound [ClGe(STsi)]2 and to the insertion product (thf)Ge[S‐GeCl2‐Tsi]2, in which additional GeCl2 molecules insert into the C−S bonds of Ge(STsi)2. The synthesis and the experimentally determined structures of all compounds are presented together with first reactivity studies of Ge(STsi)2.

Ge14Br8–xClx(PEt3)4: Insight into the Reaction Route to Metalloid Clusters of Germanium

“…Therefore, germylenes stabilized by extremely bulky ligands like terphenyl and others should be avoided, as this would probably lead to a deformation of the cluster core due to the ligand size. The reaction of Ge I Br with the germylenes Ge[N(SiMe 3 ) 2 ] 2 , 22 Ge[SC(SiMe 3 ) 3 ] 2 , 23 and Ge(Cp*) 2 24 (Cp* = C 5 R 5 ; R = CH 3 ) indicate that a reaction indeed takes place. For example, on heating a metastable Ge I Br solution in toluene/PEt 3 to room temperature, a lot of a red precipitate (Ge 14 Br 8 (PEt 3 ) 4 (1)) and a pale red colored solution is obtained.…”

1,2- and 1,1-Migratory Insertion Reactions of Silylated Germylene Adducts

“…Reactions of one or two equivalents of GeCl 2 •dioxane with the PMe 3 adduct of [(Me 3 Si) 3 Si] 2 Ge: gave either the mono-or diinsertion product of GeCl 2 insertion into the Ge-Si bonds. Only a few examples of insertion reactions of GeCl 2 into weak E-E bonds of group 14 oligomers are known [19][20][21][22], and the current chemistry seems to provide an interesting pathway to precursors for unsaturated group 14 cluster molecules.…”

“…More recently, Rivard and co-workers described the related reaction of an NHC adduct of GeCl 2 with GeCl 2 to give branched oligomers [20]. The insertion of GeCl 2 •dioxane into the Ge-P bond of a germylene phosphane adduct was reported by Wesemann and co-workers [21], whereas Schnepf and co-workers observed insertion of GeCl 2 •dioxane into the S-C bonds of [(Me 3 Si) 3 CS] 2 Ge: [22].…”

Low‐Valent Germanylidene Anions: Efficient Single‐Site Nucleophiles for Activation of Small Molecules

“…Mononuclear complexes of germanium have garnered attention as congeners of transition metals in bond activation processes. The most intensely studied chemistries in this class involve Ge II ‐Ge IV reactivity in which germanium functions primarily as a single‐site ambiphile via a Lewis acidic p‐orbital and an electron pair [1–11] . More recently, ylidones (cAAC) 2 E (cAAC=cyclic (alkyl)(amino)carbene; E=Si, Ge) A (Figure 1) featuring electron‐rich Group 14 elements formally in oxidation state zero have been put to the fore.…”

“…The most intensely studied chemistries in this class involve Ge II ‐Ge IV reactivity in which germanium functions primarily as a single‐site ambiphile via a Lewis acidic p‐orbital and an electron pair. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ] More recently, ylidones (cAAC) 2 E (cAAC=cyclic (alkyl)(amino)carbene; E=Si, Ge) A (Figure 1 ) featuring electron‐rich Group 14 elements formally in oxidation state zero have been put to the fore. Akin to transition metals, increased nucleophilicity at the metalloid is critical to effect bond activation.…”