Research ArticleChemistry

A chlorine-free protocol for processing germanium

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Science Advances  05 May 2017:
Vol. 3, no. 5, e1700149
DOI: 10.1126/sciadv.1700149
  • Fig. 1 Strategies for the synthesis of metal-organic materials.

    Steps in red represent a change in metal oxidation state, whereas those in blue are redox-neutral relative to the metal. (A) Simplified industrial life cycle of metal-containing materials. (B) Synthesis and redox isomerization of metal catecholates. (C) Aerobic oxidation of metals mediated by a quinone-catechol redox couple. (D) Synthesis of germanes from either germanium (Ge) or germanium dioxide (GeO2).

  • Fig. 2 Synthesis and structural analysis of Ge-Cat2-amine complexes 3 to 5.

    (A) General conditions for 200-mg and 1-g scale reactions using either condition A [Ge(0) (1 equiv) and 1 (2 equiv)] or condition B [GeO2 (1 equiv) and 2 (2 equiv)] along with ligand (only 1 equiv of TMEDA was used) (2 equiv), liquid (60 or 300 μl of a 1:1 volumetric mixture of PhMe/H2O), and milling frequency (30 Hz) at room temperature for 3 hours. Optimization of the reaction conditions is described in the Supplementary Materials (figs. S1 to S9). Reported yields are for isolated complexes following recrystallization. (B) Single-crystal x-ray structure for complex 3 (toluene), with toluene and hydrogens removed for clarity (fig. S43 and table S6). (C) Ge K-edge X-ray absorption spectrum of 3 using Ge(HPO4)2 and GeO2 as reference materials.

  • Fig. 3 Scope of substitution reaction.

    General conditions: 3 (250 mg), RMgCl (20 equiv), THF (10 ml), 65°C for 24 hours. aComplex 4 used in place of complex 3. bComplex 5 used in place of complex 3. cUsing MeMgBr in Bu2O; 1H NMR yield using toluene as an internal standard. dIsolated as a 10:1 mixture with bibenzyl.

  • Fig. 4 Proposed mechanism and ligand effects.

    (A) Substitution occurs by an increasingly facile replacement of the catecholate ligand with the Grignard reagent. (B) Effects of a more Lewis basic and sterically encumbered amine ligand.

  • Fig. 5 Synthesis of germane from 3.

    (A) Reaction conditions: LiAlH4 (12 mg), 3 (44 mg), room temperature, Bu2O (1 ml). (B) Isotopic distribution of GeH4 signal (EI-MS): a, calculated; b, experimental.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/5/e1700149/DC1

    Supplementary Materials and Methods

    section S1. General experimental

    section S2. General procedures

    section S3. Optimization of the mechanochemical synthesis of complex 3

    section S4. Synthesis and characterization of complexes

    section S5. Synthesis of organogermanes

    section S6. Characterization data

    section S7. Single-crystal x-ray diffraction

    fig. S1. PXRD patterns; initial experiments.

    fig. S2. PXRD data for the optimized synthesis of complex 3, exploring the liquid additive in LAG.

    fig. S3. PXRD data for the optimized synthesis of complex 3, exploring the volume of liquid additive in LAG.

    fig. S4. PXRD data for the optimized synthesis of complex 3, exploring Py equivalents.

    fig. S5. PXRD data for the optimized synthesis of complex 3, exploring different milling reaction times.

    fig. S6. PXRD data for the optimized synthesis of complex 3, exploring milling frequency.

    fig. S7. PXRD data for the optimized 1-g scale synthesis of complex 3, exploring milling frequency.

    fig. S8. PXRD data for the optimized 1-g scale synthesis of complexes 4 and 5.

    fig. S9. PXRD data for the optimized synthesis of complex 3 from GeO2.

    fig. S10. PXRD data for the optimized synthesis of complex 3 from GeO2/ZnO mixtures.

    fig. S11. Reaction apparatus for generating GeH4.

    fig. S12. 1H NMR (500 MHz, CDCl3) spectrum of complex 3.

    fig. S13. Thermogravimetric analysis (TGA) of complex 3.

    fig. S14. First derivatives of the Ge K-edge XAS of complex 3 compared to Ge(HPO4)2 and GeO2 as reference materials.

    fig. S15. 1H NMR (500 MHz, CDCl3) spectrum of complex 4.

    fig. S16. 13C NMR (125 MHz, CDCl3) spectrum of complex 4.

    fig. S17. TGA of complex 4.

    fig. S18. 1H NMR (500 MHz, CDCl3) spectrum of complex 5.

    fig. S19. 13C NMR (125 MHz, CDCl3) spectrum of complex 5.

    fig. S20. TGA of complex 5.

    fig. S21. 1H NMR (400 MHz, CDCl3) spectrum of GeBu4 (inset, expansion from 1.45 to 0.60 ppm).

    fig. S22. 13C NMR (100 MHz, CDCl3) spectrum of GeBu4 (inset, expansion from 28 to 12 ppm).

    fig. S23. 1H NMR (400 MHz, CDCl3) spectrum of GePh4 (inset, expansion from 7.65 to 7.35 ppm).

    fig. S24. 13C NMR (100 MHz, CDCl3) spectrum of GePh4 (inset, expansion from 137 to 127 ppm).

    fig. S25. 1H NMR (400 MHz, CDCl3) spectrum of GeBn4 (inset, expansion from 7.30 to 6.80 ppm).

    fig. S26. 13C NMR (100 MHz, CDCl3) spectrum of GeBn4 (inset, expansion from 128.5 to 128.0 ppm).

    fig. S27. 1H NMR (600 MHz, CDCl3) spectrum of Ge((CH2)5CH3)4 (inset, expansion from 1.40 to 0.65 ppm).

    fig. S28. 13C NMR (150 MHz, CDCl3) spectrum of Ge((CH2)5CH3)4.

    fig. S29. 1H NMR (400 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4.

    fig. S30. 1H NMR (400 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4 from 1.86 to 1.70 ppm.

    fig. S31. 1H NMR (400 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4 from 5.90 to 4.80 ppm.

    fig. S32. 13C NMR (100 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4.

    fig. S33. 1H NMR (600 MHz, CDCl3) spectrum of Ge(p-Tol)4 (inset, expansion from 7.50 to 7.15 ppm).

    fig. S34. 13C NMR (150 MHz, CDCl3) spectrum of Ge(p-Tol)4.

    fig. S35. 1H NMR (600 MHz, CDCl3) spectrum of complex 11.

    fig. S36. 1H NMR (600 MHz, CDCl3) spectrum of complex 11 from 1.55 to 0.85 ppm.

    fig. S37. 13C NMR (150 MHz, CDCl3) spectrum of complex 11.

    fig. S38. 13C NMR (150 MHz, CDCl3) spectrum of complex 11 from 112.50 to 111.50 ppm.

    fig. S39. 13C NMR (150 MHz, CDCl3) spectrum of complex 11 from 40 to 10 ppm.

    fig. S40. Two possible isomers for complex 11.

    fig. S41. Expansion of the 13C-1H HSQC spectrum of complex 11.

    fig. S42. Expansion of the 13C-1H HMBC spectrum of complex 11.

    fig. S43. Thermal ellipsoid plot of Ge(3,5-dtbc)2(Py)2·2PhMe (3).

    fig. S44. Thermal ellipsoid plot of Ge(3,5-dtbc)2(NMI)2·DCM (4).

    fig. S45. Thermal ellipsoid plot of Ge(3,5-dtbc)2(TMEDA)·2DCM (5).

    table S1. Optimization of LAG additive composition.

    table S2. Optimization of LAG additive volume.

    table S3. Optimization of Py equivalents.

    table S4. Optimization of milling time.

    table S5. Optimization of milling frequency.

    table S6. Crystal data and structure refinement parameters for complexes 3 and 5.

    References (4142)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • section S1. General experimental
    • section S2. General procedures
    • section S3. Optimization of the mechanochemical synthesis of complex 3
    • section S4. Synthesis and characterization of complexes
    • section S5. Synthesis of organogermanes
    • section S6. Characterization data
    • section S7. Single-crystal x-ray diffraction
    • fig. S1. PXRD patterns; initial experiments.
    • fig. S2. PXRD data for the optimized synthesis of complex 3, exploring the liquid additive in LAG.
    • fig. S3. PXRD data for the optimized synthesis of complex 3, exploring the volume of liquid additive in LAG.
    • fig. S4. PXRD data for the optimized synthesis of complex 3, exploring Py equivalents.
    • fig. S5. PXRD data for the optimized synthesis of complex 3, exploring different milling reaction times.
    • fig. S6. PXRD data for the optimized synthesis of complex 3, exploring milling frequency.
    • fig. S7. PXRD data for the optimized 1-g scale synthesis of complex 3, exploring milling frequency.
    • fig. S8. PXRD data for the optimized 1-g scale synthesis of complexes 4 and 5.
    • fig. S9. PXRD data for the optimized synthesis of complex 3 from GeO2.
    • fig. S10. PXRD data for the optimized synthesis of complex 3 from GeO2/ZnO mixtures.
    • fig. S11. Reaction apparatus for generating GeH4.
    • fig. S12. 1H NMR (500 MHz, CDCl3) spectrum of complex 3.
    • fig. S13. Thermogravimetric analysis (TGA) of complex 3.
    • fig. S14. First derivatives of the Ge K-edge XAS of complex 3 compared to Ge(HPO4)2 and GeO2 as reference materials.
    • fig. S15. 1H NMR (500 MHz, CDCl3) spectrum of complex 4.
    • fig. S16. 13C NMR (125 MHz, CDCl3) spectrum of complex 4.
    • fig. S17. TGA of complex 4.
    • fig. S18. 1H NMR (500 MHz, CDCl3) spectrum of complex 5.
    • fig. S19. 13C NMR (125 MHz, CDCl3) spectrum of complex 5.
    • fig. S20. TGA of complex 5.
    • fig. S21. 1H NMR (400 MHz, CDCl3) spectrum of GeBu4 (inset, expansion from 1.45 to 0.60 ppm).
    • fig. S22. 13C NMR (100 MHz, CDCl3) spectrum of GeBu4 (inset, expansion from 28 to 12 ppm).
    • fig. S23. 1H NMR (400 MHz, CDCl3) spectrum of GePh4 (inset, expansion from 7.65 to 7.35 ppm).
    • fig. S24. 13C NMR (100 MHz, CDCl3) spectrum of GePh4 (inset, expansion from 137 to 127 ppm).
    • fig. S25. 1H NMR (400 MHz, CDCl3) spectrum of GeBn4 (inset, expansion from 7.30 to 6.80 ppm).
    • fig. S26. 13C NMR (100 MHz, CDCl3) spectrum of GeBn4 (inset, expansion from 128.5 to 128.0 ppm).
    • fig. S27. 1H NMR (600 MHz, CDCl3) spectrum of Ge((CH2)5CH3)4 (inset, expansion from 1.40 to 0.65 ppm).
    • fig. S28. 13C NMR (150 MHz, CDCl3) spectrum of Ge((CH2)5CH3)4.
    • fig. S29. 1H NMR (400 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4.
    • fig. S30. 1H NMR (400 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4 from 1.86 to 1.70 ppm.
    • fig. S31. 1H NMR (400 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4 from 5.90 to 4.80 ppm.
    • fig. S32. 13C NMR (100 MHz, CDCl3) spectrum of Ge(CH2–CH=CH2)4.
    • fig. S33. 1H NMR (600 MHz, CDCl3) spectrum of Ge(p-Tol)4 (inset, expansion from 7.50 to 7.15 ppm).
    • fig. S34. 13C NMR (150 MHz, CDCl3) spectrum of Ge(p-Tol)4.
    • fig. S35. 1H NMR (600 MHz, CDCl3) spectrum of complex 11.
    • fig. S36. 1H NMR (600 MHz, CDCl3) spectrum of complex 11 from 1.55 to 0.85 ppm.
    • fig. S37. 13C NMR (150 MHz, CDCl3) spectrum of complex 11.
    • fig. S38. 13C NMR (150 MHz, CDCl3) spectrum of complex 11 from 112.50 to 111.50 ppm.
    • fig. S39. 13C NMR (150 MHz, CDCl3) spectrum of complex 11 from 40 to 10 ppm.
    • fig. S40. Two possible isomers for complex 11.
    • fig. S41. Expansion of the 13C-1H HSQC spectrum of complex 11.
    • fig. S42. Expansion of the 13C-1H HMBC spectrum of complex 11.
    • fig. S43. Thermal ellipsoid plot of Ge(3,5-dtbc)2(Py)2∙2PhMe (3).
    • fig. S44. Thermal ellipsoid plot of Ge(3,5-dtbc)2(NMI)2∙DCM (4).
    • fig. S45. Thermal ellipsoid plot of Ge(3,5-dtbc)2(TMEDA)∙2DCM (5).
    • table S1. Optimization of LAG additive composition.
    • table S2. Optimization of LAG additive volume.
    • table S3. Optimization of Py equivalents.
    • table S4. Optimization of milling time.
    • table S5. Optimization of milling frequency.
    • table S6. Crystal data and structure refinement parameters for complexes 3 and 5.
    • References (41–42)

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