Aminotroponiminatogermaacid Halides with a Ge(E)X Moiety (E = S, Se; X = F, Cl)

Fluorination of aminotroponiminate (ATI) ligand-stabilized
germylene
monochloride [(t-Bu)2ATI]­GeCl (1) with CsF gave the aminotroponiminatogermylene monofluoride [(t-Bu)2ATI]­GeF (2). Oxidative addition
reaction of compound 2 with elemental sulfur and selenium
led to isolation of the corresponding germathioacid fluoride [(t-Bu)2ATI]­Ge­(S)F (3) and germaselenoacid
fluoride [(t-Bu)2ATI]­Ge­(Se)F (4), respectively. Similarly, reaction of aminotroponiminatogermylene
monochloride [(i-Bu)2ATI]­GeCl (9) with elemental sulfur and selenium gave the aminotroponiminatogermathioacid
chloride [(i-Bu)2ATI]­Ge­(S)Cl (11) and aminotroponiminatogermaselenoacid chloride [(i-Bu)2ATI]­Ge­(Se)Cl (12), respectively. Compound 9 has been prepared through a multistep synthetic route starting
from 2-(tosyloxy)­tropone 5. All compounds (2–4 and 6–12)
were characterized through the multinuclear NMR spectroscopy, and
single-crystal X-ray diffraction studies were performed on compounds 2, 4, and 8–12. The germaselenoacid halide complexes 4 and 12 showed doublet (−142.37 ppm) and singlet (−213.13
ppm) resonances in their 77Se NMR spectra, respectively.
Germylene monohalide complexes 2 and 9 have
a germanium center in distorted trigonal pyramidal geometry, whereas
a distorted tetrahedral geometry is seen around the germanium center
in germaacid halide complexes 4, 11, and 12. The length of the GeE bond in germathioacid chloride
(11) and germaselenoacid halide (4 and 12) complexes is 2.065(1) and 2.194av Å, respectively.
Theoretical studies (based on the DFT methods) on complexes 4, 11, and 12 reveal the nature
of the GeE multiple bond in these germaacid halide complexes
with computed Wiberg bond indices (WBI) being 1.480, 1.508, and 1.541,
respectively.