476303-86-3Relevant articles and documents
Synthesis and properties of the first stable neutral germaaromatic compound, 2-{2,4,6-Tris-[bis(trimethylsilyl)methyl]phenyl}-2-germanaphthalene
Nakata, Norio,Takeda, Nobuhiro,Tokitoh, Norihiro
, p. 481 - 489 (2008/10/08)
The first stable neutral germaaromatic compound, 2-germanaphthalene 1a, was synthesized by taking advantage of an extremely bulky and efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt). The molecular structure and aromaticity of 1a were discussed on the basis of its NMR, UV-vis, and Raman spectra, X-ray crystallographic analysis, and theoretical calculations. All the 1H and 13C NMR chemical shifts of the 2-germanaphthalene ring of 1a were in good agreement with the calculated values for 2-germanaphthalene and 2-phenyl-2-germanaphthalene. The patterns of UV-vis and Raman spectra of 1a were similar to those of naphthalene, although the shift to longer wavelength (in the UV-vis spectrum) and smaller wavenumber (in the Raman spectrum) resulting from the replacement of carbon with germanium were observed. X-ray crystallographic analysis of 1a revealed that the 2-germanaphthalene ring was almost planar and perpendicular to the benzene ring of the Tbt group. These experimental results indicate the delocalization of π-electrons in the 2-germanaphthalene ring of 1a. Theoretical calculations (NICS(1), Λ, and ASEisom) also indicated the ring current effects and aromatic stabilization of 2-germanaphthalene. 2-Germanaphthalene 1a reacted as a Ge-C double-bond compound (germene) with water, t-BuLi, mesitonitrile oxide, 2,3-dimethyl-1,3-butadiene, and some elemental chalcogens to give the corresponding adducts.
