Synthesis, Spectroscopic and Structural Systematics of Complexes of Germanium(IV) Halides (GeX₄, X = F, Cl, Br or I) with Mono‐, Bi‐ and Tri‐Dentate and Macrocyclic Nitrogen Donor Ligands

Abstract

The six‐coordinate adducts cis‐[GeX4(L–L)] (L–L = 2,2′‐bipyridyl, 1,10‐phenanthroline, or Me2NCH2CH2NMe2, X = F, Cl or Br) have been synthesised and characterised by IR and VT 1H and 19F{1H} NMR spectroscopy. X‐ray crystal structures reveal distorted octahedral geometries and the trends in d(Ge–N) with halide are interpreted in terms of varying Lewis acidity within the series. The trans‐[GeX4(py)2] were similarly characterised. In contrast, GeI4 does not form similar adducts, although it appears to co‐crystallise with some of the ligands, and the structure of GeI4·(1,10‐phenH)3·I3 which contains phenanthrolinium cations, iodide anions and tetrahedral GeI4 molecules is reported. Multidentate nitrogen donor ligands including cyclam (1,4,8,11‐tetraazacyclotetradecane) and Me4‐cyclam (1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane) react with [GeF4(MeCN)2] to form insoluble compounds [{GeF4}2(macrocycle)] (F4N2 donor sets). In contrast, Me3[9]aneN3 (1,4,7‐trimethyl‐1,4,7‐triazacyclononane) forms the cation [GeF3{Me3[9]aneN3}]+ with a facial geometry (N3F3 donor set) which is the first example of displacement of fluoride from GeF4 by a neutral ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Electrodeposition from supercritical fluids

“…6,96 Many Ge(IV) complexes are moisture sensitive, whilst the thermal stability of Ge(II) complexes is often poor. Among the Ge(II) complexes explored were the commercially available GeBr 2 , a complex of the functionalised diimine [GeCl 2 (4,4 0 -didecyl-2,2 0bipyridyl)], 6 97 These two reagents were chosen as they are thermally relatively stable, and since they are coordinatively saturated, they are moisture stable solids and relatively resistant to hydrolysis in solution. Unfortunately, they proved to be insufficiently soluble in the SCFs.…”

Structural and energetic properties of haloacetonitrile – GeF4 complexes

“…Some time ago, solution-phase NMR studies [34] found that N-donor -TiF 4 and SnF 4 , complexes assumed cis geometries in spite of steric considerations, which would place the larger substituents opposite one another in a trans configuration. Interestingly, (CH 3 CN) 2 GeF 4 , is a convenient reagent for the preparation of various octahedral GeF 4 L 2 complexes [35,36], because it is reasonably stable and the CH 3 CN ligands are fairly labile, while pure GeF 4 is less convenient because it is gas at room temperature.…”

Supramolecular D⋯A-layered structures based on germanium complexes with 2,3-dihydroxynaphthalene and N,N′-bidentate ligands

“…The lengths of Ge-O bonds in it vary in the narrow range (1.847-1.863 A, Table 1), Scheme 1 Synthesis of 1-3. 26 In crystal structure of 3 (Fig. 2), aromatic C-H groups form weak C-H/O interactions with oxygen atoms of 2,3-dihydroxynaphthalene ligands.…”