Chemistry:Pentaamine(dinitrogen)ruthenium(II) chloride

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Pentaamine(dinitrogen)­ruthenium(II) chloride
RuA5N2.png
Names
IUPAC name
pentaamminedinitrogenruthenium (II) chloride
Identifiers
3D model (JSmol)
Properties
H15N7Cl2Ru
Molar mass 285.14 g/mol
Appearance colorless solid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N (what is ☑Y☒N ?)
Infobox references

Pentaamine(nitrogen)ruthenium(II) chloride is an inorganic compound with the formula [Ru(NH3)5(N2)]Cl2. It is a nearly white solid, but its solutions are yellow. The cationic complex is of historic significance as the first compound with N2 bound to a metal center.[1][2] [Ru(NH3)5(N2)]2+ adopts an octahedral structure with C4v symmetry.[3]

Preparation and properties

Pentaamine(nitrogen)ruthenium(II) chloride is synthesized in an aqueous solution from pentaamminechlororuthenium(III) chloride, sodium azide, and methanesulfonic acid:[4]

[Ru(NH3)5Cl]Cl2 + NaN3 → [Ru(NH3)5N2]Cl2 + ...

If it is to be used in situ, the cation can be made more conveniently from ruthenium(III) chloride and hydrazine hydrate:[4]

RuCl3 + 4 N2H4 → [Ru(NH3)5N2]2+ + ...

This N2 complex is stable in aqueous solution and has a relatively low ligand exchange rate with water. Being a d6 complex, the Ru-N bond is stabilized by the pi backbonding, the donation of metal d-electrons into the N2 π* orbitals.[5] The related metal ammine complex [Os(NH3)5(N2)]2+ is also known.

Reactions

The dinitrogen ligand is not reduced by aqueous sodium borohydride.[6] Nearly all known reactions of this compound are displacement reactions. Pentaamine(halogen)ruthenium(II) halides can be synthesized by treating [Ru(NH3)5N2]2+ with halide sources:[4]

[Ru(NH3)5N2]2+ + X → [Ru(NH3)5X]+ + N2

[Ru(NH3)5N2]2+ forms the symmetrically bridging symmetrical dinitrogen complex [(NH3)5Ru-NN-Ru(NH3)5]4+.[7][8]

References

  1. Alen. A. D.; Senoff, C. V. (1965) "Nitrogenopentammineruthenium(II) complexes" Chemical Communications 24: 621-2. doi:10.1039/C19650000621
  2. Senoff, C.V. (1990) "The discovery of [Ru(NH3)5NN2]2+: A case of serendipity and the scientific method" Journal of Chemical Education, volume 67: 368. doi:10.1021/ed067p368
  3. Fergusson, J. E.; Love, J. L.; Robinson, W. T. (1972) "The Crystal and Molecular Structure of Dinitrogenpentaammineosmium(II) Chloride, [Os(NH3)5N2]Cl2, and Related Ruthenium Complexes" Inorg. Chem., 11, pp. 1662–1666. doi:10.1021/ic50113a042
  4. 4.0 4.1 4.2 Allen, A. D., Bottomley, F., Harris, R. O., Reinsalu, V. P., Senoff, C. V. "Pentaammine(Nitrogen)Ruthenium(II) Salts and Other Ammines of Ruthenium" Inorganic Syntheses, 2007, volume 12, pp. 2-8. doi:10.1002/9780470132432.ch1
  5. Taube, H. "Chemistry of Ruthenium(II) and Osmium(II) Ammines" Pure and Applied Chemistry, 1979, volume 51, p. 901–12. doi:10.1351/pac197951040901
  6. J. Chatt, R. L. Richards, J. F. Fergusson and J. L. Love, "The reduction of nitrogen complexes" Chem. Commun. 1968, 1522. doi:10.1039/C19680001522
  7. D. F. Harrison, F. Weissberger and H. Taube, Science, 1968, volume 159, 320.
  8. Chatt, J. "Molecular Nitrogen as a Ligand" Pure Appl. Chem., 1970, volume 24, pp. 425–442. doi:10.1351/pac197024020425