View PDF Version
 
DOI: 10.1039/A700372B (Paper) Reference Section for: J. Chem. Soc., Faraday Trans., 1997, 93, 2467-2472

Rydberg structures in the gas-phase electronic absorption spectra of η-cycloheptatrienyl η-cyclopentadienyl complexes of molybdenum

(Note: The full text of this document is currently only available in the PDF Version )

Sergey Yu. Ketkov and Jennifer C. Green

Abstract

The gas-phase electronic absorption spectra of (Ch)(Cp)Mo and (Ch)(Cp′)Mo (Ch=η7-C7H7, Cp=η5-C5H5, Cp′=η5-C5H4CH3) have been measured for the first time and compared with those recorded in n-heptane solution. The gas-phase spectra reveal rich Rydberg structures which disappear on going to the solution phase. The Rydberg bands correspond to transitions from the non-bonding molybdenum 4dz2 orbital to Rns, Rnp and Rnd levels. On the basis of analysis of Rydberg frequencies, the first ionization potentials of (Ch)(Cp)Mo and (Ch)(Cp′)Mo have been determined as 45890 cm-1 (5.69 eV) and 45300 cm-1 (5.62 eV), respectively. Assignments based on term values and effective quantum numbers of the Rydberg transitions have been made. The R5s, R5p and R5d bands reveal vibronic components assigned to totally symmetric CC stretches, CH umbrella vibrations and metal–ring skeletal modes. Methylation of (Ch)(Cp)Mo results in splitting of the R5px,y and R5dxz,yz transitions and appearance of the R5dxy and R5dx2-y2 excitations. These changes are in agreement with a molecular symmetry reduction from C∞v to Cs. The spectrum of (Ch)(Cp′)Mo gives the first example of an interpretable structure of the lowest Rnp and Rnd transitions in a methylated sandwich complex. The differences between the Rydberg structures of the (Ch)(Cp)Mo and (Ch)(Cp′)Mo spectra in the n>5 region are due to changes in Rydberg–valence interactions and relative band intensities on methylation.

References

  1. S. Yu. Ketkov, J. Organomet. Chem., 1992, 429, C38 CrossRef CAS.
  2. J. C. Green, M. L. H. Green, C. N. Field, D. K. P. Ng and S. Yu. Ketkov, J. Organomet. Chem., 1995, 501, 107 CrossRef CAS.
  3. S. Yu. Ketkov, G. A. Domrachev and G. A. Razuvaev, Opt. Spectrosc. (USSR), 1987, 63, 167 Search PubMed.
  4. G. A. Domrachev, S. Yu. Ketkov and G. A. Razuvaev, J. Organomet. Chem., 1987, 328, 341 CrossRef CAS.
  5. S. Yu. Ketkov, G. A. Domrachev and G. A. Razuvaev, J. Mol. Struct., 1989, 195, 175 CrossRef CAS.
  6. S. Yu. Ketkov and G. A. Domrachev, J. Organomet. Chem., 1990, 389, 187 CrossRef CAS.
  7. S. Yu. Ketkov, C. Mehnert and J. C. Green, Chem. Phys., 1996, 203, 245 CrossRef CAS.
  8. S. Yu. Ketkov and G. A. Domrachev, Inorg. Chim. Acta, 1990, 178, 233 CrossRef CAS.
  9. S. Yu. Ketkov and G. A. Domrachev, J. Organomet. Chem., 1991, 420, 67 CrossRef CAS.
  10. S. Yu. Ketkov, Opt. Spectrosc. (USSR), 1992, 72, 595 Search PubMed.
  11. S. Yu. Ketkov, J. Organomet. Chem., 1994, 465, 225 CrossRef CAS.
  12. S. Yu. Ketkov, Russ. Chem. Bull., 1994, 43, 583 CrossRef.
  13. J. C. Green and S. Yu. Ketkov, Organometallics, 1996, 15, 4747 CrossRef CAS.
  14. J. C. Green, Struct. Bonding (Berlin), 1981, 43, 37 CAS.
  15. F. G. N. Cloke, A. N. Dix, J. C. Green, M. L. H. Green, N. J. Hazel, P. D. Grebenik, V. S. Mtetwa and K. Prout, Organometallics, 1983, 2, 1150 CrossRef CAS.
  16. J. C. Green, M. L. H. Green, N. Kaltsonyannis, P. Mountford, P. Scott and S. J. Simpson, Organometallics, 1992, 11, 3353 CrossRef CAS.
  17. J. C. Green, N. Kaltsonyannis, K. H. Sze and M. Macdonald, J. Am. Chem. Soc., 1994, 116, 1994 CrossRef CAS.
  18. D. W. Clack and K. D. Warren, Struct. Bonding (Berlin), 1980, 39, 1 CAS.
  19. J. D. Zeinstra and W. C. Nieuwpoort, Inorg. Chim. Acta, 30, 103 Search PubMed.
  20. M. L. H. Green, D. K. P. Ng and R. C. Tovey, J. Chem. Soc., Chem. Commun., 1992, 918 RSC.
  21. M. L. H. Green, D. K. P. Ng, R. C. Tovey and A. N. Chernega, J. Chem. Soc., Dalton Trans., 1993, 3203 RSC.
  22. M. B. Robin, Higher Excited States of Polyatomic Molecules, Academic Press, New York, vol. 1, 1974 Search PubMed.
  23. J. Sugar and C. Cortiss, J. Phys. Chem. Ref. Data, 1977, 6, 317 CAS.
  24. J. M. Hossenlopp, D. Rooney, B. Samoriski, G. Bowen and J. Chaiken, Chem. Phys. Lett., 1985, 116, 380 CrossRef CAS.
  25. B. Samoriski and J. Chaiken, Phys. Rev. A, 1988, 38, 3498 CrossRef CAS.
  26. L. Schaefer, J. F. Southern and S. J. Cyvin, Spectrochim. Acta, Part A, 1971, 27, 1083 CrossRef CAS.
  27. S. J. Cyvin, J. Brunvoll and L. Schaefer, J. Chem. Phys., 1971, 54, 1517 CrossRef CAS.
  28. J. Brunvoll, S. J. Cyvin and L. Schaefer, J. Organomet. Chem., 1971, 27, 69 CrossRef CAS.
  29. T. V. Long and F. R. Huege, Chem. Commun., 1968, 1239 Search PubMed.
  30. J. Brunvoll, S. J. Cyvin and L. Shaefer, J. Organomet. Chem., 1971, 27, 107 CrossRef CAS.
  31. I. I. Greenwald and B. V. Lokshin, J. Mol. Struct., 1990, 218, 255 CrossRef.
  32. H. W. Wehner, E. O. Fischer and J. Muller, Chem. Ber., 1970, 103, 2258 CAS.
  33. M. B. Robin, Higher Excited States of Polyatomic Molecules, Academic Press, Orlando, vol. 3 1985 and references therein Search PubMed.
Click here to see how this site uses Cookies. View our privacy policy here.