Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Perspective
  • Published:

Dimeric magnesium(I) β-diketiminates: a new class of quasi-universal reducing agent

Nature Reviews Chemistry volume 1, Article number: 0059 (2017) Cite this article

Subjects

Abstract

Since the first report of their isolation in 2007, magnesium(I) dimers have transitioned from being chemical curiosities to versatile reducing agents that are used by an ever-increasing number of synthetic chemists. Magnesium(I) dimers have a unique combination of advantageous properties that sees them used in the syntheses of new, and often applicable, compound types that are impossible or difficult to access using conventional reductants. This Perspective describes the synthesis and properties of these dimers, and provides notable examples of their application in organic and inorganic synthesis. Magnesium(I) dimers, especially complexes of β-diketiminates, may now be viewed as widely applicable, quasi-universal reducing agents with a promising future in synthetic chemistry. It is hoped that the reader will develop a familiarity with these reagents, such that the complexes can be successfully used in many synthetic programmes.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Oxidation potentials for reductants that are commonly used in organic and organometallic synthesis.
Figure 2: Dimagnesium(I) complexes of the form [Mg2(Arnacnac)2].

Similar content being viewed by others

References

  1. Connelly, N. G. & Geiger, W. E. Chemical redox agents for organometallic chemistry. Chem. Rev. 96, 877–910 (1996).

    Article  CAS  Google Scholar 

  2. Szostak, M., Spain, M. & Procter, D. J. Recent advances in the chemoselective reduction of functional groups mediated by samarium(II) iodide: a single electron transfer approach. Chem. Soc. Rev. 42, 9155–9183 (2013).

    Article  CAS  Google Scholar 

  3. Cintas, P. in Activated metals in organic synthesis (CRC, 1993).

    Google Scholar 

  4. Evans, W. J. Perspectives in reductive lanthanide chemistry. Coord. Chem. Rev. 206–207, 263–283 (2000).

    Article  Google Scholar 

  5. Szostak, M., Spain, M. & Procter, D. J. Determination of the effective redox potentials of SmI2, SmBr2, SmCl2, and their complexes with water by reduction of aromatic hydrocarbons. Reduction of anthracene and stilbene by samarium(II) iodide–water complex. J. Org. Chem. 79, 2522–2537 (2014).

    Article  CAS  Google Scholar 

  6. Emsley, J. The elements (Clarendon, 1991).

    Google Scholar 

  7. Green, S. P., Jones, C. & Stasch, A. Stable magnesium(I) compounds with Mg–Mg bonds. Science 318, 1754–1757 (2007).

    Article  CAS  Google Scholar 

  8. Boutland, A. J., Dange, D., Stasch, A., Maron, L. & Jones, C. Two-coordinate magnesium(I) dimers stabilized by super bulky amido ligands. Angew. Chem. Int. Ed. 55, 9239–9243 (2016).

    Article  CAS  Google Scholar 

  9. Köppe, R., Henke, P. & Schnöckel, H. MgCl and Mg2Cl2: from theoretical and thermodynamic considerations to spectroscopy and chemistry of species with Mg–Mg bonds. Angew. Chem. Int. Ed. 47, 8740–8744 (2008).

    Article  Google Scholar 

  10. Liu, Y., Li, S., Yang, X.-J., Yang, P. & Wu, B. Magnesium–magnesium bond stabilized by a doubly reduced α-diimine: synthesis and structure of [K(THF)3]2[LMg–MgL] (L = [(2,6-iPr2C6H3)NC(Me)]22−). J. Am. Chem. Soc. 131, 4210–4211 (2009).

    Article  CAS  Google Scholar 

  11. Boutland, A. J., Pernik, I., Stasch, A. & Jones, C. Magnesium(I) dimers bearing tripodal diimine–enolate ligands: proficient reagents for the controlled reductive activation of CO2 and SO2 . Chem. Eur. J. 21, 15749–15758 (2015).

    Article  CAS  Google Scholar 

  12. Stasch, A. & Jones, C. Stable dimeric magnesium(I) compounds: from chemical landmarks to versatile reagents. Dalton Trans. 40, 5659–5672 (2011).

    Article  CAS  Google Scholar 

  13. Jones, C. & Stasch, A. Stable molecular magnesium(I) dimers: a fundamentally appealing yet synthetically versatile compound class. Top. Organomet. Chem. 45, 73–102 (2013).

    Article  CAS  Google Scholar 

  14. Jones, C., Mountford, P., Stasch, A. & Blake, M. P. in Molecular Metal–Metal Bonds. Compounds, Synthesis, Properties (ed. Liddle, S. T. ) 23–46 (Wiley, 2015).

    Google Scholar 

  15. Bonyhady, S. J. et al. β-Diketiminate-stabilized magnesium(I) dimers and magnesium(II) hydride complexes: synthesis, characterization, adduct formation, and reactivity studies. Chem. Eur. J. 16, 938–955 (2010).

    Article  CAS  Google Scholar 

  16. Lalrempuia, R. et al. Activation of CO by hydrogenated magnesium(I) dimers: sterically controlled formation of ethenediolate and cyclopropanetriolate complexes. J. Am. Chem. Soc. 137, 8944–8947 (2015).

    Article  CAS  Google Scholar 

  17. Overgaard, J., Jones, C., Stasch, A. & Iversen, B. B. Experimental electron density study of the Mg–Mg bonding character in a magnesium(I) dimer. J. Am. Chem. Soc. 131, 4208–4209 (2009).

    Article  CAS  Google Scholar 

  18. Green, S. P., Jones, C. & Stasch, A. Stable adducts of a dimeric magnesium(I) compound. Angew. Chem. Int. Ed. 47, 9079–9083 (2008).

    Article  CAS  Google Scholar 

  19. Platts, J. A., Overgaard, J., Jones, C., Iversen, B. B. & Stasch, A. First experimental characterisation of a non-nuclear attractor in a dimeric magnesium(I) compound. J. Phys. Chem. A 115, 194–200 (2011).

    Article  CAS  Google Scholar 

  20. Wu, L.-C., Jones, C., Stasch, A., Platts, J. A. & Overgaard, J. Non-nuclear attractor in a molecular compound under external pressure. Eur. J. Inorg. Chem. 2014, 5536–5540 (2014).

    Article  CAS  Google Scholar 

  21. Holm, T. & Crossland, I. in Grignard Reagents: New Developments Ch.1 (ed. Richley, H. G. Jr. ) (Wiley, 2000).

    Google Scholar 

  22. Reike, R. D. Chemical Synthesis Using Highly Reactive Metals Ch.4 (Wiley, 2017).

    Book  Google Scholar 

  23. Rausch, M. D., McEwen, W. E. & Kleinberg, J. Reductions involving unipositive magnesium. Chem. Rev. 57, 417–437 (1957).

    Article  CAS  Google Scholar 

  24. Jones, C., McDyre, L., Murphy, D. M. & Stasch, A. Magnesium(I) reduction of benzophenone and anthracene: first structural characterisation of a magnesium ketyl. Chem. Commun. 46, 1511–1513 (2010).

    Article  CAS  Google Scholar 

  25. Gomberg, M. & Bachmann, W. E. The reducing action of a mixture of magnesium iodide (or bromide) and magnesium on aromatic ketones. Probable formation of magnesium subiodide (or subbromide). J. Am. Chem. Soc. 49, 236–257 (1927).

    Article  CAS  Google Scholar 

  26. Bonyhady, S. J., Green, S. P., Jones, C., Nembenna, S. & Stasch, A. A dimeric magnesium(I) compound as a facile two-center/two-electron reductant. Angew. Chem. Int. Ed. 48, 2973–2977 (2009).

    Article  CAS  Google Scholar 

  27. Lalrempuia, R., Stasch, A. & Jones, C. The reductive disproportionation of CO2 using a magnesium(I) complex: analogies with low valent f-block chemistry. Chem. Sci. 4, 4383–4388 (2013).

    Article  CAS  Google Scholar 

  28. Moilanen, J. O., Day, B. M., Pugh, T. & Layfield, R. A. Open-shell doublet character in a hexaazatrinaphthylene trianion complex. Chem. Commun. 51, 11478–11481 (2015).

    Article  CAS  Google Scholar 

  29. Ma, M., Stasch, A. & Jones, C. Magnesium(I) dimers as reagents for the reductive coupling of isonitriles and nitriles. Chem. Eur. J. 18, 10669–10676 (2012).

    Article  CAS  Google Scholar 

  30. Fohlmeister, L. & Jones, C. Low-valent iron complexes stabilised by a bulky guanidinate ligand: synthesis and reactivity studies. Aust. J. Chem. 67, 1011–1016 (2014).

    Article  CAS  Google Scholar 

  31. Evans, W. J. & Drummond, D. K. Reactivity of isocyanides with (C5Me5)2Sm(THF)2: synthesis and structure of trimeric [(C5Me5)2Sm(CNC6H11)(μ-CN)]3 . Organometallics 7, 797–802 (1988).

    Article  CAS  Google Scholar 

  32. Bakewell, C., White, A. J. P. & Crimmin, M. R. Addition of carbon–fluorine bonds to a Mg(I)–Mg(I) bond: an equivalent of Grignard formation in solution. J. Am. Chem. Soc. 138, 12763–12766 (2016).

    Article  CAS  Google Scholar 

  33. Kefalidis, C. E., Stasch, A., Jones, C. & Maron, L. On the mechanism of the reaction of a magnesium(I) complex with CO2. A concerted type of pathway. Chem. Commun. 50, 12318–12321 (2014).

    Article  CAS  Google Scholar 

  34. Anker, M. D., Hill, M. S., Lowe, J. P. & Mahon, M. F. Alkaline-earth-promoted CO homologation and reductive catalysis. Angew. Chem. Int. Ed. 54, 10009–10011 (2015).

    Article  CAS  Google Scholar 

  35. Power, P. P. Main group elements as transition metals. Nature 463, 171–177 (2010).

    Article  CAS  Google Scholar 

  36. Asay, M., Jones, C. & Driess, M. N-Heterocyclic carbene-analogues with low-valent group 13 and group 14 elements: syntheses, structures and reactivities of a new generation of multitalented ligands. Chem. Rev. 111, 354–396 (2011).

    Article  CAS  Google Scholar 

  37. Martin, D., Soleilhavoup, M. & Bertrand, G. Stable singlet carbenes as mimics for transition metal centers. Chem. Sci. 2, 389–399 (2011).

    Article  CAS  Google Scholar 

  38. Stasch, A. Synthesis of a dimeric magnesium(I) compound by an MgI/MgII redox reaction. Angew. Chem. Int. Ed. 53, 10200–10203 (2014).

    Article  CAS  Google Scholar 

  39. Braunschweig, H., Damme, A., Dewhurst, R. D. & Vargas, A. Bond-strengthening π backdonation in a transition-metal π-diborene complex. Nat. Chem. 5, 115–121 (2013).

    Article  CAS  Google Scholar 

  40. Bonhady, S. J. et al. Synthesis of a stable adduct of dialane(4) (Al2H4) via hydrogenation of a magnesium(I) dimer. Nat. Chem. 2, 865–869 (2010).

    Article  Google Scholar 

  41. Wang, X., Andrews, L., Tam, S., DeRose, M. E. & Fajardo, M. E. Infrared spectra of aluminum hydrides in solid hydrogen: Al2H4 and Al2H6 . J. Am. Chem. Soc. 125, 9218–9228 (2003).

    Article  CAS  Google Scholar 

  42. Bonhady, S. J., Holzmann, N., Frenking, G., Stasch, A. & Jones, C. Synthesis, characterisation and computational analysis of the dialanate dianion, [H3Al–AlH3]2−: a valence isoelectronic analogue of ethane. Angew. Chem. Int. Ed., 56, 8527–8531 (2017).

    Article  Google Scholar 

  43. Gish, J. T., Popov, I. A. & Boldyrev, A. I. Homocatenation of aluminum: alkane-like structures of Li2Al2H6 and Li3Al3H8 . Chem. Eur. J. 21, 5307–5310 (2015).

    Article  CAS  Google Scholar 

  44. Jones, C., Bonhady, S. J., Nembenna, S. & Stasch, A. New routes to soluble magnesium amidoborane complexes. Eur. J. Inorg. Chem. 2012, 2596–2601 (2012).

    Article  CAS  Google Scholar 

  45. Lee, V. Y. & Sekiguchi, A. Organometallic Compounds of Low-Valent Si, Ge, Sn and Pb: From Phantom Species to Stable Compounds (Wiley, 2010).

    Book  Google Scholar 

  46. Sidiropoulos, A., Jones, C., Stasch, A., Klein, S. & Frenking, G. N-Heterocyclic carbene stabilized digermanium(0). Angew. Chem. Int. Ed. 48, 9701–9704 (2009).

    Article  CAS  Google Scholar 

  47. Jones, C., Sidiropoulos, A., Holzmann, N., Frenking, G. & Stasch, A. An N-heterocyclic carbene adduct of diatomic tin, :Sn=Sn:. Chem. Commun. 48, 9855–9857 (2012).

    Article  CAS  Google Scholar 

  48. Wang, Y. Z. et al. A stable silicon(0) compound with a Si=Si double bond. Science 321, 1069–1071 (2008).

    Article  CAS  Google Scholar 

  49. Jones, C., Bonhady, S. J., Holzmann, N., Frenking, G. & Stasch, A. The preparation, characterization and theoretical analysis of group 14 element(I) dimers: a case study of magnesium(I) compounds as reducing agents in inorganic synthesis. Inorg. Chem. 50, 12315–12325 (2011).

    Article  CAS  Google Scholar 

  50. Choong, S. L., Schenk, C., Stasch, A., Dange, D. & Jones, C. Contrasting reductions of group 14 metal(II) chloride complexes: synthesis of the first β-diketiminato tin(I) dimer. Chem. Commun. 48, 2504–2506 (2012).

    Article  CAS  Google Scholar 

  51. Rit, A., Campos, J., Niu, H. & Aldridge, S. A stable heavier group 14 analogue of vinylidene. Nat. Chem. 8, 1022–1026 (2016).

    Article  CAS  Google Scholar 

  52. Sindlinger, C. P., Aicher, F. S. W. & Wesemann, L. Cationic stannylenes: in situ generation and NMR spectroscopic characterization. Inorg. Chem. 56, 548–560 (2017).

    Article  CAS  Google Scholar 

  53. Hadlington, T. J., Hermann, M., Li, J., Frenking, G. & Jones, C. Activation of H2 by a multiply bonded amido–digermyne: evidence for the formation of a hydrido–germylene. Angew. Chem. Int. Ed. 52, 10199–10203 (2013).

    Article  CAS  Google Scholar 

  54. Li, J., Schenk, C., Goedecke, C., Frenking, G. & Jones, C. A digermyne with a Ge–Ge single bond that activates dihydrogen in the solid state. J. Am. Chem. Soc. 133, 18622–18625 (2011).

    Article  CAS  Google Scholar 

  55. Hermann, M., Goedecke, C., Jones, C. & Frenking, G. Reaction pathways for addition of H2 to amido-ditetrylynes, R2N–EE–NR2 (E = Si, Ge, Sn). A theoretical study. Organometallics 32, 6666–6673 (2013).

    Article  CAS  Google Scholar 

  56. Li, J., Hermann, M., Frenking, G. & Jones, C. The facile reduction of CO2 to CO with an amido-digermyne. Angew. Chem. Int. Ed. 51, 8611–8614 (2012).

    Article  CAS  Google Scholar 

  57. Hadlington, T. J. et al. The reactivity of amido-digermynes, LGeGeL (L = bulky amide), towards olefins and related molecules: facile reduction, C–H activation and reversible cycloaddition of unsaturated substrates. Organometallics 34, 3175–3185 (2015).

    Article  CAS  Google Scholar 

  58. Hadlington, T. J., Hermann, M., Frenking, G. & Jones, C. Two-coordinate group 14 element(II) hydrides as reagents for the facile, and sometimes reversible, hydrogermylation/hydrostannylation of unactivated alkenes and alkynes. Chem. Sci. 6, 7249–7257 (2015).

    Article  CAS  Google Scholar 

  59. Hadlington, T. J., Hermann, M., Frenking, G. & Jones, C. Low coordinate germanium(II) and tin(II) hydride complexes: efficient catalysts for the hydroboration of carbonyl compounds. J. Am. Chem. Soc. 136, 3028–3031 (2014).

    Article  CAS  Google Scholar 

  60. Hadlington, T. J., Kefalidis, C. E., Maron, L. & Jones, C. Efficient reduction of carbon dioxide to methanol equivalents catalyzed by two-coordinate amido–germanium(II) and tin(II) hydride complexes. ACS Catal. 7, 1853–1859 (2017).

    Article  CAS  Google Scholar 

  61. Woodul, W. D. et al. A neutral, monomeric germanium(I) radical. J. Am. Chem. Soc. 133, 10074–10077 (2011).

    Article  CAS  Google Scholar 

  62. Asay, M., Inoue, S. & Driess, M. Aromatic ylide-stabilized carbocyclic silylene. Angew. Chem. Int. Ed. 50, 9589–9592 (2011).

    Article  CAS  Google Scholar 

  63. Rekken, B. D., Brown, T. M., Fettinger, J. C., Tuononen, H. M. & Power, P. P. Isolation of a stable, acyclic, two-coordinate silylene. J. Am. Chem. Soc. 134, 6504–6507 (2012).

    Article  CAS  Google Scholar 

  64. Wiederkehr, J., Wölper, C. & Schulz, S. Synthesis and solid state structure of a metalloid tin cluster [Sn10(trip8)]. Chem. Commun. 52, 12282–12285 (2016).

    Article  CAS  Google Scholar 

  65. Wagner, M. et al. [Me2C{SnCH(SiMe3)2}2]2. A μ-Me2C-bridged tetrastanna tetrahedrane. Chem. Commun. 51, 153–156 (2015).

    Article  CAS  Google Scholar 

  66. Hupp, F. et al. Platinum complexes containing pyramidalized germanium and tin dihalide ligands bound through σ,σ M=E multiple bonds. Chem. Eur. J. 20, 16888–16898 (2014).

    Article  CAS  Google Scholar 

  67. Ganesamoorthy, C., Wölper, C., Nizovtsev, A. S. & Schulz, S. Synthesis and structural characterization of magnesium-substituted polystibides [(LMg)4Sb8]. Angew. Chem. Int. Ed. 55, 4204–4209 (2016).

    Article  CAS  Google Scholar 

  68. Ganesamoorthy, C., Krüger, J., Wölper, C., Nizovtsev, A. S. & Schulz, S. Reduction of [Cp*Sb]4 with subvalent main-group metal reductants: syntheses and structures of [(L1Mg)4(Sb4)] and [(L2Ga)2(Sb4)] containing edge-missing Sb4 units. Chem. Eur. J. 23, 1–9 (2017).

    Article  Google Scholar 

  69. Fohlmeister, L. et al. Low-coordinate iron(I) and manganese(I) dimers: kinetic stabilization of an exceptionally short Fe–Fe multiple bond. Angew. Chem. Int. Ed. 51, 8294–8298 (2012).

    Article  CAS  Google Scholar 

  70. Fohlmeister, L. & Jones, C. Stabilisation of carbonyl free amidinato-manganese(II) hydride complexes: “masked” sources of manganese(I) in organometallic synthesis. Dalton Trans. 45, 1436–1442 (2016).

    Article  CAS  Google Scholar 

  71. Hoyer, C. E. et al. A two-coordinate manganese(0) complex with an unsupported Mn–Mg bond: allowing access to low coordinate homo- and hetero-bimetallic compounds. J. Am. Chem. Soc. 136, 5283–5286 (2014).

    Article  Google Scholar 

  72. Stasch, A. Synthesis, structure, and reactivity of a dimeric zinc(I) compound stabilized by a sterically demanding diiminophosphinate ligand. Chem. Eur. J. 18, 15105–15112 (2012).

    Article  CAS  Google Scholar 

  73. Hicks, J., Underhill, E. J., Kefalidis, C. E., Maron, L. & Jones, C. A mixed-valence tri-zinc complex, LZnZnZnL (L = bulky amide), bearing a linear chain of two-coordinate zinc atoms. Angew. Chem. Int. Ed. 54, 10000–10004 (2015).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

The author thanks the Australian Research Council and the US Air Force Asian Office of Aerospace Research and Development for funding.

Author information

Authors and Affiliations

  1. Cameron Jones is at the School of Chemistry, Monash University, PO Box 23, Melbourne, VIC 3800, Australia.,

    Cameron Jones

Authors
  1. Cameron Jones
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Cameron Jones.

Ethics declarations

Competing interests

The author declares no competing interests.

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Jones, C. Dimeric magnesium(I) β-diketiminates: a new class of quasi-universal reducing agent. Nat Rev Chem 1, 0059 (2017). https://doi.org/10.1038/s41570-017-0059

Download citation

  • Published:

  • DOI: https://doi.org/10.1038/s41570-017-0059

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing