Skip to main content
SpringerLink
Log in

A kinetic investigation into the rate of chloride substitution from chloro terpyridine platinum(II) and analogous complexes by a series of azole nucleophiles

  • Published:
Transition Metal Chemistry Aims and scope Submit manuscript

Abstract

The substitution kinetics of the complexes [Pt(terpy)Cl]Cl·2H2O (PtL1), [Pt(tBu3terpy)Cl]ClO4 (PtL2), [Pt{4′-(2′′′-CH3-Ph)terpy}Cl]BF4 (PtL3), [Pt{4′-(2′′′-CF3-Ph)terpy}Cl]CF3SO3 (PtL4), [Pt{4′-(2′′′-CF3-Ph)-6-Ph-bipy}Cl] (PtL5) and [Pt{4′-(2′′′-CH3-Ph)-6-2′′-pyrazinyl-2,2′-bipy}Cl]CF3SO3 (PtL6) with the nucleophiles imidazole (Im), 1-methylimidazole (MIm), 1,2-dimethylimidazole (DIm), pyrazole (Pyz) and 1,2,4-triazole (Trz) were investigated in a methanolic solution of constant ionic strength. Substitution of the chloride ligand from the metal complexes by the nucleophiles was investigated as a function of nucleophile concentration and temperature under pseudo first-order conditions using UV/Visible and stopped-flow spectrophotometric techniques. The reactions follow the rate law \( k_{\text{obs}} = k_{2} \left[ {\text{Nu}} \right] + k_{ - 2} \). The results indicate that changing the nature or distance of influence of the substituents on the terpy moiety affects the π-back-donation ability of the chelate. This in turn controls the electrophilicity of the metal centre and hence its reactivity. Electron-donating groups decrease the reactivity of the metal centre, while electron-withdrawing groups increase the reactivity. Placing a strong σ-donor cis to the leaving group greatly decreases the reactivity of the complex, while the addition of a good π-acceptor group significantly enhances the reactivity. The results indicate that the metal is activated differently by changing the surrounding atoms even though they are part of a conjugated system. It is also evident that substituents in the cis position activate the metal centre differently to those in the trans position. The kinetic results are supported by DFT calculations, which show that the metal centre is less electrophilic when a strong σ-donor is cis to the leaving group and more electrophilic when a good π-acceptor group is part of the ring moiety. The temperature dependence studies support an associative mode of activation. An X-ray crystal structure of Pyz bound to PtL3 was obtained and confirmed the results of the DFT calculations as to the preferred N-atom as a binding site.

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
Fig. 6
Fig. 7

Similar content being viewed by others

References

  1. Lippert B (1999) Cisplatin. chemistry and biochemistry of a leading anticancer drug. Wiley-VCH, Weinheim, pp 3–27

    Book  Google Scholar 

  2. Sigel A, Sigel H (1996) Metal ions in biological systems. Marcel Dekker Inc, New York, p 393

    Google Scholar 

  3. Richens DT (2005) Chem Rev 105:1961

    Article  CAS  Google Scholar 

  4. Tobe ML, Burgess J (1999) Inorganic reaction mechanisms. Addison Wesley Longman Ltd., Essex, pp 30–43, 70–112

  5. Atwood JD (1997) Inorganic and organometallic reaction mechanisms, 2nd edn. Wiley-VCH Inc, New York, pp 43–61

    Google Scholar 

  6. Jordan RB (1991) Reaction mechanisms of inorganic and organometallic systems. Oxford University Press Inc, Oxford, pp 29–74

    Google Scholar 

  7. Wilkins RG (1991) Kinetics and mechanism of reactions transition metal complexes, 2nd edn. VCH, Weinheim, pp 199–201, 221, 232–242

  8. Cross RJ (1989) Adv Inorg Chem 34:219

    Article  CAS  Google Scholar 

  9. Banerjee P (1999) Coord Chem Rev 190–192:19–28

  10. Romeo R (1990) Comments Inorg Chem 11:21

    Article  CAS  Google Scholar 

  11. Faraone G, Ricevuto V, Romeo R, Trozzi M (1971) J Chem Soc A 1877

  12. Basolo F (1996) Coord Chem Rev 154:151

    Article  CAS  Google Scholar 

  13. Millard MM, Macquet JP, Theophanides T (1975) Biochim Biophys Acta 402:166

    CAS  Google Scholar 

  14. Sigel H, Massoud SS, Corfu NA (1994) J Am Chem Soc 116:2958

    Article  CAS  Google Scholar 

  15. Bugarčić ZD, Nandibewoor AT, Hamza MSA, Heinemann F, van Eldik R (2006) Dalton Trans 2984

  16. Kaim W, Schwederski B (1994) Bioinorganic chemistry: inorganic elements in the chemistry of life, 1st edn. Wiley, New York, pp 16–35, 106–123

  17. Pitteri B, Bortoluzzi M (2006) Polyhedron 25:2698

    Article  CAS  Google Scholar 

  18. Sundberg RJ, Martin RB (1974) Chem Rev 74:471

    Article  CAS  Google Scholar 

  19. Carlsen L, Egsgaard H, Anderson JR (1979) Anal Chem 51:1593

    Article  CAS  Google Scholar 

  20. Kröhnke F (1976) Synthesis 1

  21. McDermott JX, White JF, Whitesides GM (1976) J Am Chem Soc 98:6521

    Article  CAS  Google Scholar 

  22. Annibale G, Brandolisio M, Pitteri B (1995) Polyhedron 14:451

    Article  CAS  Google Scholar 

  23. Lai S-W, Chan MCW, Cheung K-K, Che C-M (1998) Inorg Chem 38:4262

    Article  Google Scholar 

  24. Summerton GC (1997) Solid state structures and photophysical properties of polypyridyl complexes of platinum(II). PhD thesis, University of Natal, Pietermaritzburg, South Africa, p 51, 53, pp 71–77, 94–107, 150–156

  25. Field JS, Haines RJ, McMillin DR, Summerton GC (2002) J Chem Soc Dalton Trans 1369

  26. Gertenbach JA (2002) Synthesis and emission studies of polypyridyl complexes of platinum(II). PhD thesis University of Natal, Pietermaritzburg, South Africa, pp 220–230, 260–262

  27. Jaganyi D, Reddy D, Gertenbach JA, Hofmann A, van Eldik R (2004) Dalton Trans 299–304

  28. Spartan ‘08, Wavefunction, Inc. (2008) 18401 Von Karman Avenue, Suite 370, Irvine, CA, 92612, USA; Q-Chem, Inc., The Design Center, Suite 690, 5001 Baum Blvd., Pittsburgh, PA, 15213, USA. http://www.wavefun.com/

  29. Kong J, White CA, Krylov AI, Sherrill CD, Adamson RD, Furlani TR, Lee MS, Lee AM, Gwaltney SR, Adams TR, Ochsenfeld C, Gilbert ATB, Kedziora GS, Rassolov VA, Maurice DR, Nair N, Shao Y, Besley NA, Maslen PE, Dombroski JP, Daschel H, Zhang W, Korambath PP, Baker J, Byrd EFC, Van Voorhuis T, Oumi M, Hirata S, Hsu C-P, Ishikawa N, Florian J, Warshel A, Johnson BG, Gill PMW, Head-Gordon M, Pople JA (2000) J Comput Chem 21:1532

    Article  CAS  Google Scholar 

  30. Becke AD (1993) J Chem Phys 98:5648

    Article  CAS  Google Scholar 

  31. Friesner RA (1985) Chem Phys Lett 116:39

    Article  CAS  Google Scholar 

  32. Friesner RA (1991) Ann Rev Phys Chem 42:341

    Article  CAS  Google Scholar 

  33. Hay PJ, Wadt WR (1985) J Chem Phys 82:299

    Article  CAS  Google Scholar 

  34. Reddy D, Jaganyi D (2008) Dalton Trans 6724

  35. Katritzky R, Rees CW (1984) Comprehensive heterocyclic chemistry, vol 5. Pergamon Press, Oxford, pp 35–50, 169–225, 374–386, 734–747

  36. Appleton TG, Hall JR, Ralph SF, Thompson CSM (1984) Inorg Chem 23:3521

    Article  CAS  Google Scholar 

  37. CrysAlis CCD and CrysAlis RED (2002) Version 170, Oxford Diffraction Ltd., Abingdon

  38. Sheldrick GM (1997) SHELXS-97, Program for solution of crystal and structures. University of Göttingen, Germany

    Google Scholar 

  39. Sheldrick GM (1997) SHELXL-97, Program for refinement of crystal structures. University of Göttingen, Germany

    Google Scholar 

  40. Blessing R (1995) Acta Cryst A51:33

    CAS  Google Scholar 

  41. Farrugia J (1999) WinGX v1.70.01. J Appl Cryst 32:837

    Article  CAS  Google Scholar 

  42. Mercury (2008) Version 2.2. Cambridge Crystallographic Data Centre, Cambridge

    Google Scholar 

  43. Microcal™ Origin™ (1991–1997) Version 5.0, Microcal Software, Inc., One Roundhouse Plaza, Northampton, MA, 01060, USA

  44. Rosić J, Petrović B, Djuran MI, Bugarčić ZD (2007) Monatshefte für Chemie 138:1

    Article  Google Scholar 

  45. Roszak AW, Clement O, Buncel E (1996) Acta Cryst C52:1654

    Google Scholar 

  46. Muller J, Freisinger E, Lax P, Megger DA, Polonius F (2007) Inorg Chim Acta 360:255

    Article  Google Scholar 

  47. Jaganyi D, De Boer KL, Gertenbach JA, Perils J (2008) Int J Chem Kinet 808–818

  48. Jaganyi D, Hofmann A, van Eldik R (2001) Angew Chem Int Ed 40:1680

    Article  CAS  Google Scholar 

  49. Hofmann A, Jaganyi D, Munro OQ, Liehr G, van Eldik R (2003) Inorg Chem 42:1688

    Article  CAS  Google Scholar 

  50. Jaganyi D, Reddy D, Gertenbach JA, Hofmann A, van Eldik R (2004) Dalton Trans 299–304

  51. Hofmann A, Dahlenburg L, van Eldik R (2003) Inorg Chem 42:6528

    Article  CAS  Google Scholar 

  52. Pitteri B, Marangoni G, Viseutim FV, Cattalini L, Bobbo T (1998) Polyhedron 17:475–482

    Article  CAS  Google Scholar 

Download references

Acknowledgments

The authors gratefully acknowledge financial support from the University of KwaZulu-Natal and the National Research Foundation (NRF, Pretoria). We thank Mr C. Grimmer for the NMR analysis of the samples.

Author information

Authors and Affiliations

  1. School of Chemistry, University of KwaZulu-Natal, Private Bag X01 Scottsville, Pietermaritzburg, 3209, South Africa

    Desigan Reddy, Kate J. Akerman, Matthew P. Akerman & Deogratius Jaganyi

Authors
  1. Desigan Reddy
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Kate J. Akerman
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Matthew P. Akerman
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Deogratius Jaganyi
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding authors

Correspondence to Desigan Reddy or Deogratius Jaganyi.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOC 3375 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Reddy, D., Akerman, K.J., Akerman, M.P. et al. A kinetic investigation into the rate of chloride substitution from chloro terpyridine platinum(II) and analogous complexes by a series of azole nucleophiles. Transition Met Chem 36, 593–602 (2011). https://doi.org/10.1007/s11243-011-9507-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11243-011-9507-x

Keywords

Search

Navigation