Article | Published:

Neutral zero-valent s-block complexes with strong multiple bonding

Nature Chemistry volume 8, pages 890894 (2016) | Download Citation

Subjects

Abstract

The metals of the s block of the periodic table are well known to be exceptional electron donors, and the vast majority of their molecular complexes therefore contain these metals in their fully oxidized form. Low-valent main-group compounds have recently become desirable synthetic targets owing to their interesting reactivities, sometimes on a par with those of transition-metal complexes. In this work, we used stabilizing cyclic (alkyl)(amino)carbene ligands to isolate and characterize the first neutral compounds that contain a zero-valent s-block metal, beryllium. These brightly coloured complexes display very short beryllium–carbon bond lengths and linear beryllium coordination geometries, indicative of strong multiple Be–C bonding. Structural, spectroscopic and theoretical results show that the complexes adopt a closed-shell singlet configuration with a Be(0) metal centre. The surprising stability of the molecule can be ascribed to an unusually strong three-centre two-electron π bond across the C–Be–C unit.

  • Compound

    1,2-bis(1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene)diboryne

  • Compound

    1,2-bis(1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene)ditin

  • Compound

    1,2-bis(1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene)diphosphorus

  • Compound

    bis(1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene)germylone

  • Compound

    1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidinium tetrafluoroborate

  • Compound

    2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4,5]dec-1-enium tetrafluoroborate

  • Compound

    1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene

  • Compound

    2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4,5]decan-1-ylidene

  • Compound

    1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene beryllium dichloride

  • Compound

    2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4,5]decan-1-ylidene beryllium dichloride

  • Compound

    bis(1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene)beryllium

  • Compound

    (1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene)(2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4,5]decan-1-ylidene)beryllium

  • Compound

    1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-selenone

  • Compound

    (1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene) carbon dioxide adduct

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    Organotransition Metal Chemistry: From Bonding to Catalysis (University Science Books, 2010).

  2. 2.

    N-Heterocyclic Carbenes: Effective Tools for Organic Synthesis 111–146, 371–394 (Wiley-VCH, 2014).

  3. 3.

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

  4. 4.

    Reactions of heavier main group compounds with hydrogen, ammonia, ethylene and related small molecules. Chem. Rec. 12, 238–255 (2012).

  5. 5.

    & Reactivity of white phosphorus with compounds of the p-block. Coord. Chem Rev. 255, 1342–1359 (2011).

  6. 6.

    & Recent advances in the field of main-group mono- and diatomic ‘allotropes’ stabilised by neutral ligands. Chem. Eur. J. 19, 13626–13637 (2013).

  7. 7.

    et al. Ambient-temperature isolation of a compound with a boron–boron triple bond. Science 336, 1420–1422 (2008).

  8. 8.

    et al. An N-heterocyclic carbene adduct of diatomic tin, :Sn=Sn:. Chem. Commun. 48, 9855–9857 (2012).

  9. 9.

    et al. Carbene-stabilized diphosphorus. J. Am. Chem. Soc. 130, 14970–14971 (2008).

  10. 10.

    et al. A stable singlet biradicaloid siladicarbene: (L:)2Si. Angew. Chem. Int. Ed. 52, 2963–2967 (2013).

  11. 11.

    et al. Acyclic germylones: congeners of allenes with a central germanium atom. J. Am. Chem. Soc. 135, 12422–12428 (2013).

  12. 12.

    Compounds of alkali metal anions. Angew. Chem. Int. Ed. 18, 587–598 (1979).

  13. 13.

    et al. Beryllium chemistry the safe way: a theoretical evaluation of low oxidation state beryllium compounds. Dalton Trans. 42, 11375–11384 (2013).

  14. 14.

    & Neutral tricoordinated beryllium(0) compounds—isostructural to BH3 but isoelectronic to NH3. Dalton Trans. 42, 4650–4656 (2013).

  15. 15.

    , & Stable magnesium(I) compounds with Mg–Mg bonds. Science 318, 1754–1757 (2007).

  16. 16.

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

  17. 17.

    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).

  18. 18.

    et al. Three-coordinate beryllium β-diketiminates: synthesis and reduction chemistry. Inorg. Chem. 51, 13408–13418 (2012).

  19. 19.

    , & Synthesis and structure of an ionic beryllium–‘carbene’ complex. J. Organomet. Chem. 501, C1–C4 (1995).

  20. 20.

    & The first carbene complex of a diorganoberyllium: synthesis and structural characterization of Ph2Be(i-Pr-carbene) and Ph2Be(n-Bu2O). Organometallics 25, 3784–3786 (2006).

  21. 21.

    et al. Carbene-stabilized beryllium borohydride. J. Am. Chem. Soc. 134, 9953–9955 (2012).

  22. 22.

    , & Activation of N-heterocyclic carbenes by {BeH2} and {Be(H)(Me)} fragments. Organometallics 34, 653–662 (2015).

  23. 23.

    & Quantifying and understanding the electronic properties of N-heterocyclic carbenes. Chem. Soc. Rev. 42, 6723–6753 (2013).

  24. 24.

    & Cyclic (alkyl)(amino)carbenes (CAACs): stable carbenes on the rise. Acc. Chem. Res. 48, 256–266 (2015).

  25. 25.

    & Synthesis, 9Be NMR spectroscopy, and structural characterization of sterically encumbered beryllium compounds. Inorg. Chem. 36, 4688–4696 (1997).

  26. 26.

    et al. Bonding situation in Be[N(SiMe3)2]2—an experimental and computational study. Chem. Commun. 51, 3889–3891 (2015).

  27. 27.

    et al. Beryllium bis(diazaborolyl): old neighbors finally shake hands. Chem. Commun. 51, 737–740 (2015).

  28. 28.

    , & A N-heterocyclic carbene gold hydroxide complex: a golden synthon. Chem. Commun. 46, 2742–2744 (2010).

  29. 29.

    , , & Synthesis of homoleptic and heteroleptic bis-N-heterocyclic carbene group 11 complexes. Organometallics 34, 419–425 (2015).

  30. 30.

    et al. Synthesis and structures of alkaline-earth metal supersilanides: tBu3SiMX and tBu3Si−M−SitBu3 (M = Be, Mg; X = Cl, Br). Eur. J. Inorg. Chem. 666–670 (2003).

  31. 31.

    et al. Lewis-base stabilized diiodine adducts with N-heterocyclic chalcogenamides. Dalton Trans. 42, 12940–12946 (2013).

  32. 32.

    , , & Reactivity of cyclic (alkyl)(amino)carbenes (CAACs) and bis(amino)cyclopropenylidenes (BACs) with heteroallenes: comparisons with their N-heterocyclic carbene (NHCs) counterparts. Chem. Asian J. 4, 1745–1750 (2009).

  33. 33.

    Computational Chemistry: Introduction to the Theory and Applications of Molecular and Quantum Mechanics (Springer Verlag, 2011).

  34. 34.

    & Divalent carbon(0) chemistry, Part 1: parent compounds. Chem. Eur. J. 14, 3260–3272 (2008).

  35. 35.

    , & Transition metal−carbon complexes. A theoretical study. J. Am. Chem. Soc. 129, 7596–7610 (2007).

  36. 36.

    et al. Formation and characterization of the boron dicarbonyl complex [B(CO)2]. Angew. Chem. Int. Ed. 54, 11078–11083 (2015).

  37. 37.

    et al. Air-stable (CAAC)CuCl and (CAAC)CuBH4 complexes as catalysts for the hydrolytic dehydrogenation of BH3NH3. Angew. Chem. Int. Ed. 54, 6008–6011 (2015).

  38. 38.

    , & Potassium–graphite as a metalation reagent. Synthesis of aldehydes and ketones by alkylation of imines and dihydro-1,3-oxazine. J. Org. Chem. 43, 2907–2910 (1978).

  39. 39.

    A short history of ShelX. Acta Crystallogr. A 64, 112–122 (2008).

  40. 40.

    et al. Gaussian 09, Revision D.01 (Gaussian, Inc., Wallingford, Connecticut, 2009).

  41. 41.

    Density-functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 98, 5648–5652 (1993).

  42. 42.

    Density-functional exchange-energy approximation with correct asymptotic behavior. Phys. Rev. A 38, 3098–3100 (1988).

  43. 43.

    , & Development of the Colle–Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 37, 785–789 (1988).

  44. 44.

    , , & Self-consistent molecular orbital methods. XX. A basis set for correlated wave functions. J. Chem. Phys. 72, 650–654 (1980).

  45. 45.

    et al. Predicting 9Be nuclear magnetic resonance chemical shielding tensors utilizing density functional theory. J. Am. Chem. Soc. 126, 14651–14658 (2004).

  46. 46.

    & The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06 functionals and 12 other functionals. Theor. Chem. Acc. 120, 215–241 (2008).

  47. 47.

    , & Fully optimized contracted gaussian basis sets for atoms Li to Kr. J. Chem. Phys. 97, 2571–2577 (1992).

  48. 48.

    , & Design of density functionals by combining the method of constraint satisfaction with parametrization for thermochemistry, thermochemical kinetics, and noncovalent interactions. J. Chem. Theory Comput. 2, 364–382 (2006).

  49. 49.

    , , & Climbing the density functional ladder: nonempirical meta-generalized gradient approximation designed for molecules and solids. Phys. Rev. Lett. 91, 146401 (2003).

  50. 50.

    & Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: design and assessment of accuracy. Phys. Chem. Chem. Phys. 7, 3297–3305 (2005).

  51. 51.

    Advances in Chemical Physics Vol. 399 (John Wiley & Sons, Inc., 2007).

  52. 52.

    , & A combined charge and energy decomposition scheme for bond analysis. Chem. Theory Comput. 5, 962–975 (2009).

  53. 53.

    & On the calculation of bonding energies by the Hartree–Fock–Slater method. Theor. Chim. Acta 46, 1–10 (1977).

  54. 54.

    , & Roothaan–Hartree–Fock–Slater atomic wave functions. Single-zeta, double-zeta, and extended Slater-type basis sets for 87Fr-103Lr. At. Data Nucl. Data Tables 26, 483–509 (1981).

  55. 55.

    , & Relativistic regular two-component Hamiltonians. J. Chem. Phys. 99, 4597–4610 (1993).

  56. 56.

    , & A new hybrid exchange–correlation functional using the Coulomb-attenuating method (CAM-B3LYP). Chem. Phys. Lett. 393, 51–57 (2004).

  57. 57.

    , , & New developments in the polarizable continuum model for quantum mechanical and classical calculations on molecules in solution. J. Chem. Phys. 117, 43–54 (2002).

Download references

Acknowledgements

Financial support from the Julius-Maximilians-Universität Würzburg (H.B.) and the Alexander von Humboldt Foundation (postdoctoral fellowship to M.A.) is gratefully acknowledged. We also thank G. Frenking for helpful discussions regarding the computational analysis.

Author information

Affiliations

  1. Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

    • Merle Arrowsmith
    • , Holger Braunschweig
    • , Mehmet Ali Celik
    • , Theresa Dellermann
    • , Rian D. Dewhurst
    • , William C. Ewing
    • , Kai Hammond
    • , Thomas Kramer
    • , Ivo Krummenacher
    • , Jan Mies
    • , Krzysztof Radacki
    •  & Julia K. Schuster

Authors

  1. Search for Merle Arrowsmith in:

  2. Search for Holger Braunschweig in:

  3. Search for Mehmet Ali Celik in:

  4. Search for Theresa Dellermann in:

  5. Search for Rian D. Dewhurst in:

  6. Search for William C. Ewing in:

  7. Search for Kai Hammond in:

  8. Search for Thomas Kramer in:

  9. Search for Ivo Krummenacher in:

  10. Search for Jan Mies in:

  11. Search for Krzysztof Radacki in:

  12. Search for Julia K. Schuster in:

Contributions

J.K.S. designed the study under the supervision of H.B., performed all the reactions and collected and analysed the data. J.M. carried out preliminary synthetic work on compound 3. M.A.C. and W.C.E. performed the theoretical calculations. I.K. collected the CV data. K.H. synthesized the starting materials. T.D., T.K. and K.R. collected and refined the crystallographic data. W.C.E., M.A.C., M.A. and R.D.D. wrote the paper. All the authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Holger Braunschweig.

Supplementary information

PDF files

  1. 1.

    Supplementary information

    Supplementary information

Crystallographic information files

  1. 1.

    Supplementary information

    Crystallographic data for compound 1

  2. 2.

    Supplementary information

    Crystallographic data for compound 2

  3. 3.

    Supplementary information

    Crystallographic data for compound 3

  4. 4.

    Supplementary information

    Crystallographic data for compound 4

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nchem.2542

Further reading