247245-92-7Relevant academic research and scientific papers
The first kinetically stabilized germanethiones and germaneselones: Syntheses, structures, and reactivities
Matsumoto, Tsuyoshi,Tokitoh, Norihiro,Okazaki, Renji
, p. 8811 - 8824 (2008/04/18)
The first kinetically stabilized germanethiones (germanium-sulfur double-bond species) and germaneselones (germanium-selenium double-bond species) were synthesized. Dechalcogenation of the novel 1,2,3,4,5-tetrachalcogenagermolane Tbt(TiP)GeX4 (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Tip = 2,4,6-triisopropylphenyl, X = S or Se) with 3 molar equiv of triphenylphosphine gave diaryl-substituted germanethione Tbt(Tip)Ge=S 1a and germaneselone Tbt(Tip)Ge=Se 2a as orange-yellow crystals and red crystals, respectively, which were unstable in air but thermally quite stable. Chalcogenation of germylene Tbt(Dis)Ge: resulted in the isolation of the corresponding germanethione Tbt(Dis)Ge-S 1b and germaneselone Tbt(Dis)Ge=Se 2b (Dis = bis(trimethylsilyl)methyl). The molecular structures of germanethione 1a and germaneselones 2a,b determined by X-ray crystallographic analysis indicate that they have trigonal planar geometies around the germanium atom and a remarkably shorter Ge-S (2.049(3) A for 1a) or Ge-Se bond lengths (2.180(2) A for 2a and 2.173(3) A for 2b), compared with that of typical single bonds. The double-bond characters are also reflected in their spectral data such as UV/vis (1a, 450 nm; 1b, 432 nm; 2a, 519 nm; 2b, 492 nm), Raman (1a, 521 cm-1; 1b, 512 cm-1; 2a, 381 cm-1; 2b, 386 cm-1), and 77Se NMR (2a, 941 ppm; 2b, 872 ppm). The germanethiones and germaneselones underwent [2 + 2] (with phenyl isothiocyanate), [3 + 2] (with mesitonitrile oxide), and [4 + 2] cycloadditions (with 1,3-dienes) to give the corresponding adducts in high yields. The regioselectivities of the [4 + 2] cycloadditions were examined using unsymmetrical dienes such as isoprene and interpreted in terms of the interaction between LUMO of the Ge=X unit and HOMO of the diene part.
The chemistry of germanium-containing heavy ketones
Tokitoh, Norihiro,Matsumoto, Tsuyoshi,Okazaki, Renji
, p. 1665 - 1684 (2007/10/03)
The recent applications of an extremely bulky and efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as Tbt in this article), to the kinetic stabilization of a series of doubly bonded compounds between germanium and heavier chalcogen atoms (we coin the expression 'germanium-containing heavy ketones' for this family of heavier congeners of germanone) are described. Combination of a Tbt group with some other bulky aromatic or alkyl substituent enabled us to synthesize the novel germanium-containing double-bond species [Tbt(R)Ge=X; R = 2,4, 6- triisopropylphenyl (Tip) or bis(trimethylsilyl)methyl (Dis)] such as germanethiones (X = S), germaneselones (X = Se), and germanetellones (X = Te) as stable crystalline compounds, while the germanone [Tbt(Tip)Ge=O], the most reactive species among the germanium-containing heavy ketones, was found to be very difficult to isolate and was evidenced only by the trapping reactions. The X-ray crystallographic analysis of the isolated germanium- containing heavy ketones revealed a completely trigonal planar geometry around their germachalcogenocarbonyl units and their ideally doubly bonded character, which was also confirmed by their spectroscopic data.
