Advertisement

Epilogue

  • Nicolaos Demetrios Epiotis
Part of the Lecture Notes in Chemistry book series (LNC, volume 34)

Abstract

As the amount of experimental research reported in the literature continually increases, as the number os scientific journals grows unabated, and as theory becomes more and more sophisticated because of continual forward strides in computer technology, experimentalists can no longer afford to use primitive concepts in their daily planning of syntheses and their quests of new mechanisms as well as in communications with collegues and educating students. For the same reasons, theoreticians can no longer pretend to interpret the results of highly complex computations through usage of elementary qualitative MO concepts. This two part work attempts to establish a common language for experimentalists and theoreticians alike for discussing, analyzing, and resolving chemical problems and for rationally designing “new chemistry”. This new language makes principal use of the MOVB bond diagrammatic representation of the electronic structure of molecules. Our goal has been to teach this new formalism so that the reader can come to the point that, by a few strokes of the pen, i.e., by the construction of one or more bond diagrams, he can resolve controversial issues, rectify mistaken impressions, and predict new phenomena, without the need of explicit computations and without the necessity of lengthy discussions and clarifications.

Keywords

Primitive Concept Ground Triplet Daily Planning Mistaken Impression Multicenter Bond 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Shaw, R., in “The Chemistry of Cyanates and their Thio Derivatives”, Part 1, Patai, S., Ed.; John Wiley and Sons: New York, 1977.Google Scholar
  2. 2.
    The trend defined by 2 and 3 was first noted by: Turco, A., Pecile, C., Nature 1961, 191, 66. For review, see: Burmeister, J.L., Coord. Chem. Rev. 1968, 3, 225. The “pi bonding competition” hypothesis advanced to explain this trend is not valid. This can be easily shown by construction and comparison of appropriate bond diagrams.Google Scholar
  3. 3.
    Ambident selectivity in the weak binding regime has been correctly analyzed in an MO frame by: Klopman, G. J. Am. Chem. Soc. 1968, 90, 223. See also: Hudson, R. F. Angew. Chem., Int. Ed. Engl. 1973, 12, 36.CrossRefGoogle Scholar
  4. 4.
    Schleyer, P. von R.; Würthwein, E-U.; People, J. A. J. Am. Chem. Soc. 1982, 104, 5839.CrossRefGoogle Scholar
  5. 5.
    For a discussion of one such controversy, see: Epiotis, N. D., Cherry, W.R., Shaik, S., Yates, R.L., Bernardi, F., Topics Curr. Chem. 1977, 70, 1 (and especially p. 160).Google Scholar
  6. 6.
    Corriu, R. J. P. ; Geurin, C. Advan. Organomet. Chem. 1982, 20, 265.CrossRefGoogle Scholar
  7. 7.
    This conclusion has also been reached in an MO frame: Anh, N. T.; Minot, C. J. Am. Chem. Soc. 1980, 102, 103.CrossRefGoogle Scholar
  8. 8.
    For example, see Chapter 6 in Pearson, R.G., “Symmetry Rules for Chemical Reactions”; John Wiley and Sons: New York, 1976.Google Scholar
  9. 9.
    a) Demoulin, D., Chem. Phys. 1975, 11, 329. This paper first reported calculations, which show that 3B lie below 3A but 1A lie below 1B states!Google Scholar
  10. (b).
    Schaefer, III, H. F.; Wetmore, R. W. J. Chem. Phys. 1987, 69, 1648.Google Scholar
  11. (c).
    Janoschek, R., Winkelhofer, G., Fratev, F., presented in part at the IUPAC Symposium on Theoretical Organic Chemistry, Dubrovnik, August 1982. I thank Professor Janoschek for a copy of the manuscript prior to publication.Google Scholar
  12. 10.
    The (expected) impotence of Walsh diagrams (see, inter alia: Walsh, A.D., J. Chem. Soc. 1953, 2288) to deal with many facets of the problems discussed in this section has been pointed out in ref. 9b and 9c.Google Scholar
  13. 11.
    Collman, J. P. Accounts Chem. Res. 1977, 10, 265.CrossRefGoogle Scholar
  14. 12.
    Construction of bond diagrams reveal that the following species are disfavored, insofar as bonds are concerned, relative to the staggered II because:Google Scholar
  15. 1).
    Eclipsed II with excited triplet O2 has one pi and one sigma Fe(II) - O2 bonds and one pi and one weak delta Fe(II) - O2 antibonds.Google Scholar
  16. 2).
    Eclipsed II with ground triplet O2 has one pi and one weak delta Fe(II) - O2 bonds and a sigma and a pi Fe(II) - O2 antibonds.Google Scholar
  17. 3).
    Staggered II with ground triplet O2 has only one pi Fe(II) - O2 bond (if all Fe(II) - P sigma bonds are to be preserved) and three Fe(II) - O2 antibonds (two pi and one sigma). The reader will find checking these results an excellent practice in MOVB theory.Google Scholar
  18. 13. (a)
    Guilard, R., Fontesse, M., Fournari, P., Lecomte, C., Protas, J., Chem. Commun. 1976, 161.Google Scholar
  19. (b).
    Guilard, R.; Latour, J.-M.; Lecomte, C.; Marchon, J.-C.; Protas, J.; Ripoll, D.; Inorg. Chem. 1978, 17, 1228.CrossRefGoogle Scholar
  20. 14.
    Dedieu, A., Rohmer, M.-M., Veillard, H., Veillard, A., Nouveau J. Chem. 1979, 3, 653. This paper contains also an excellent review of the experimental facts and the theoretical computations targeted to them.Google Scholar
  21. 15.
    Triplet II is obtained by relocating an electron from π*z to dyz. Thus, two 2-electron are replaced by one 1-electron and one 3-electron bonds.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1983

Authors and Affiliations

  • Nicolaos Demetrios Epiotis
    • 1
  1. 1.Department of ChemistryUniversity of WashingtonSeattleUSA

Personalised recommendations