Skip to main content
SpringerLink
Log in

Disproportionation of pentaammineruthenium(III)–nucleoside complexes leads to two-electron oxidation of nucleosides without involving oxygen molecules

  • Original Paper
  • Published:
JBIC Journal of Biological Inorganic Chemistry Aims and scope Submit manuscript

Abstract

Pentaammineruthenium(III) complexes of deoxyinosine (dIno) and xanthosine (Xao) ([RuIII(NH3)5(L)], L is dIno, Xao) in basic solution were studied by UV–vis spectroscopy, liquid chromatography/electrospray ionization mass spectrometry, and high-performance liquid chromatography. Both RuIII complexes disproportionate to RuII and RuIV. Disproportionation followed the rate law d[RuII]/dt = (k o + k 1[OH−])[RuIII]. k o and k 1 of disproportionation at 25 °C were 2.1 (±0.1) × 10−3 s−1 and 21.4 ± 3.2 M−1 s−1, respectively, for [RuIII(NH3)5(dIno)], and 3.5 (±0.7) × 10−4 s−1 and 59.7 ± 3.6 M−1 s−1, respectively, for [RuIII(NH3)5(Xao)]. The [RuIII(NH3)5(Xao)] complex disproportionates at a faster rate than [RuIII(NH3)5(dIno)] owing to the stronger electron-withdrawing effect of exocyclic oxygen in Xao. The activation parameters ΔH ‡ and ΔS ‡ for k 1 of [RuIII(NH3)5(dIno)] were 80.2 ± 15.2 kJ mol−1 and 47.6 ± 9.8 J K−1 mol−1, respectively, indicating that the disproportionation of RuIII to RuII and RuIV is favored owing to the positive entropy of activation. The final products of both complexes in basic solution under Ar were compared with those under O2. Under both conditions [Ru(NH3)5(8-oxo-L)] was produced, but via different mechanisms. In both aerobic and anaerobic conditions, the deprotonation of highly positively polarized C8-H of Ru-L by OH− initiates a two-electron redox reaction. For the next step, we propose a one-step two-electron redox reaction between L and RuIV under anaerobic conditions, which differentiates from Clarke’s mechanism of two consecutive one-electron redox reactions between L, RuIII, and O2.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Scheme 1
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Scheme 2
Scheme 3

Similar content being viewed by others

Abbreviations

Cyclic-dGuo:

Cyclic 5′-O-C8-2′-deoxyguanosine

dGuo:

2′-Deoxyguanosine

dIno:

2′-Deoxyinosine

Guo:

Guanosine

HPLC:

High-performance liquid chromatography

Ino:

Inosine

LC:

Liquid chromatography

MS:

Mass spectrometry

Xao:

Xanthosine

References

  1. Rudd DP, Taube H (1971) Inorg Chem 10:1543–1544

    Article  Google Scholar 

  2. LaChance-Galang KJ, Zhao M, Clarke MJ (1996) Inorg Chem 35:6021–6026

    Article  CAS  Google Scholar 

  3. Zhao M, Clarke MJ (1999) J Biol Inorg Chem 4:318–324

    Article  PubMed  CAS  Google Scholar 

  4. Zhao M, Clarke MJ (1999) J Biol Inorg Chem 4:325–340

    Article  PubMed  CAS  Google Scholar 

  5. Choi S, Ryu D, DellaRocca JG, Wolf MW, Bogart JA (2011) Inorg Chem 50:6567–6574

    Article  PubMed  CAS  Google Scholar 

  6. Becker BF (2011) Nucleosides Nucleotides Nucleic Acids 30:1161

    Article  PubMed  CAS  Google Scholar 

  7. Vongchampa V, Dong M, Gingipalli L, Dedon P (2003) Nucleic Acids Res 31:1045–1051

    Article  PubMed  CAS  Google Scholar 

  8. Steenken S, Jovanovic SV (1997) J Am Chem Soc 119:617–618

    Article  CAS  Google Scholar 

  9. Kim J (2000) Bull Korean Chem Soc 21:709–711

    CAS  Google Scholar 

  10. Clarke MJ, Taube H (1974) J Am Chem Soc 96:5413–5419

    Article  CAS  Google Scholar 

  11. Clarke MJ (1977) Inorg Chem 16:738–744

    Article  CAS  Google Scholar 

  12. Gariepy KC, Curtin MA, Clarke MJ (1989) J Am Chem Soc 111:4947–4952

    Article  CAS  Google Scholar 

  13. Rodriguez-Bailey VM, LaChance-Galang KJ, Doan PE, Clarke MJ (1997) Inorg Chem 36:1873–1883

    Article  PubMed  CAS  Google Scholar 

  14. Subranamanian P, Ji X, van der Helm D, Dryhurst G (1990) J Org Chem 55:1291–1296

    Article  Google Scholar 

Download references

Acknowledgment

This work was supported by the National Science Foundation (grant CHE-0848072).

Author information

Authors and Affiliations

  1. Department of Chemistry and Biochemistry, Middlebury College, Middlebury, VT, 05753, USA

    Matthew W. Wolf & Sunhee Choi

Authors
  1. Matthew W. Wolf
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Sunhee Choi
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Sunhee Choi.

Electronic supplementary material

Below is the link to the electronic supplementary material.

775_2012_942_MOESM1_ESM.pdf

MS spectra of experimental and theoretical [RuIII(NH3)5(L)] (Fig. S1). UV–vis spectra of [RuII(NH3)5(Xao)] and [RuIII(NH3)5(Xao)] along with kinetic data. (Fig. S2). k obs vs OH− concentration for the disproportionation of [RuIII(NH3)5(dIno)] (Fig. S3). k obs versus OH− concentration for the disproportionation of [RuIII(NH3)5(Xao)] (Fig. S4). ln(k 1/T) versus 1/T for the disproportionation of [RuIII(NH3)5(dIno)] at 20, 25, 30, and 35 °C. (Fig. S5). (PDF 260 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Wolf, M.W., Choi, S. Disproportionation of pentaammineruthenium(III)–nucleoside complexes leads to two-electron oxidation of nucleosides without involving oxygen molecules. J Biol Inorg Chem 17, 1283–1291 (2012). https://doi.org/10.1007/s00775-012-0942-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00775-012-0942-8

Keywords

Search

Navigation