Synthesis and Structures of an Unusual Germanium(II) Calix[4]arene Complex and the First Germanium(II) Calix[8]arene Complex and Their Reactivity with Diiron Nonacarbonyl

Abstract

The protonolysis reaction of the germanium(II) amide Ge[N(SiMe3)2]2 with calix[4]arene and calix[8]arene furnishes the two germanium(II) calixarene complexes {calix[4]}Ge2 and {calix[8]}Ge4, respectively, which have been crystallographically characterized. The calix[4]arene complex contains a Ge2O2 rhombus at the center of the molecule and is one of the only four germanium(II) calix[4]arenes that have been structurally characterized. The calix[8]arene species is the first reported germanium calix[8]arene complex, and it exhibits an overall bowl-shaped structure which contains two Ge2O2 fragments. The latter complex reacts with Fe2(CO)9 to yield an octairon compound, which has also been structurally characterized and contains four GeFe2 triangles arranged around the macrocyclic ring. The germanium(II) centers are oxidized to germanium(IV) in this process, with concomitant reduction of the neutral diiron species to Fe2(CO)(8)2- anions.

Synthesis and Characterization of Germanium Coordination Compounds for Production of Germanium Nanomaterials

“…The internal Ge 2 O 2 core has angles of (μ-O)-Ge-(μ-O) (av 72.5°) and Ge-(μ-O)-Ge (av 107.4°). These data are in agreement with the literature Ge(OR) 2 distances and angles [45, 84] : Ge-O (av 1.82 Å), Ge-(μ-O) (av 1.98 Å), and (μ-O)-Ge-(μ-O) (av 72.2°) Ge-(μ-O)-Ge (av 107.5 Å). For the more sterically hindering DPP ligand, monomeric 3 was isolated in a bent arrangement as previously reported by Rothwell and co-workers; [45] however, for this crystal solution, 3 was solved in the higher-ordered orthorhombic space group.…”

Porous Ge@C materials via twin polymerization of germanium(ii) salicyl alcoholates for Li-ion batteries

“…The germanium oxygen bond lengths [O Aryl -Ge bonds: 1.8408(19)Å-1.848(2)Å, O Alkyl -Ge bonds: 1.939(2)Å-1.988(2)Å] are in the typical ranges reported for Ge-O bonds in compounds with a threefold pyramidal coordination of low valent germanium. [69][70][71] The values reported for the germanium oxygen bonds for (4) 3 [O Aryl -Ge bonds: 1.829(2)Å-1.890(2)Å, O Alkyl -Ge bonds: 1.945(2) A-2.044(2)Å] resemble those in (1) 3 but are slightly longer [with the exception of Ge3-O5: 1.8447(19)Å for (1) 3 and 1.829(3)Å for (4) 3 ] due to sterically more demanding substituents at the aromatic moieties in (4) 3 . 68 The shorter Ge1-O2 [1.986(2)Å], Ge3-O6 [1.951(2)Å] and Ge2-O4 [1.939(2)Å] bonds in comparison to the Ge1-O4 [1.975(2)Å], Ge3-O2 [1.988(2)Å] and Ge2-O6 [1.988(2)Å] bond lengths, respectively, indicate secondary bonding of O4 / Ge1, O6 / Ge2 and O2 / Ge3 stabilizing the low valent species.…”

Calix[8]arenes Solid-State Structures: Derivatization and Crystallization Strategies

“…Heavy group 14 and 15 elements are represented by germanium and bismuth in terms of crystallographically characterized calix[8]arenes. One of the Ge 2+ derivatives assembles from benzene as two rhombic Ge 2 O 2 dimers with bridging oxygen donors, as well as one terminal phenolate ligand for each germanium (II) resulting in a tetragermanium-p-H-calix[8]arene complex that acquires a deep bowl shape (Wetherby et al, 2007). The lone pair on each Ge 2+ allows them to act as donors towards Fe 2 (CO) 8 fragments in a formal oxidation to Ge 4+ ; as a consequence of the oxidation process each resulting germanium (IV) is bound to only two oxygen atoms from the calixarene.…”