Electronic Structure of Flavins. Inclusion of Methyl Groups in Molecular Orbital Treatments of Flavins

  • Published : 1972.06.30

Abstract

Various MO methods with differing degrees of sophistication are shown to yield qualitatively consistent results for methyl isoalloxazins. However, with crude methods such as the HMO and ${\omega}$-technique, the choice of Coulomb and resonance integralsis critical, in contrast with simpler molecular systems. The empirical value of ${\omega}$=0.5 appears to be more reasonable than 1.4. Methyl groups in these flaving are best treated by the group orbital approximation. The pseudo-heteroatom approximation overestimates methyl hyperconfiguration with the Pariser-Parrpole SCR MO method. siglet ${\pi}{\rightarrow}{\pi}^*$ transition energies are calculated by the P-P-P method and agree reasonably with the experimental values. 2- and 4-Thioisoalloxazine analogs are also treated. Reactivity indices of the flavin molecule are presented, includeing superdelocalizability. frontier orbital and radical densities. Various aspects of the applications of these indices of the methyl groups on dipolemoments, inozation potentialsm elctron affinities, and spectra are decribed in detail.

Keywords

References

  1. J. Chem. Phys. v.21 R.Pariser;R.G.Parr
  2. Trans. Farad. Soc. v.49 J.A.Pople
  3. Internarl. J. Quantum Chem. v.1 P.S.Song;T.A. Moore
  4. Arch. Biochem. Biophys. v.122 J.A.Anderson;P.S.Song
  5. Introduction to Quiantum Chemistry T.Yonezawa;C. Nagata;H.Kato;A. Imamura;K. Morokuma
  6. Molec. Phys. v.11 H.Looyenga
  7. Advances in Quantum Chemistry v.3 K. Ohno;P.-O. Lowdin(ed.)
  8. Advances in Quantum chemistry v.2 I.Fischer-Hjalmars
  9. Bull. Chem. Soc. Japan v.40 A.Imamura;H.Fujita;C.Nagata
  10. Molec. Phys. v.11 P. Knowlton;W.R.Carper
  11. Theoret. Chim. Acta v.7 A. Denis;A. Pullman
  12. Photochem. Photobiol. v.7 P.S.Song
  13. Bull. Chim. Soc. v.15 A. Pullman;J. Metzger
  14. Osaka Daigagu Igaku Z. v.8 M.Mizutani
  15. Quantum Chemistry, Interscience R. Daudel;R. Lefebvre;C. Moser
  16. Physica. v.1 T.Koopmans
  17. Theoret. Chim. Acta v.9 R.L.Flurry, Jr.
  18. Bond Energies, Ionization Potentials and Electron Affinities V.I.Vedeneyev;L.V. Gurvich;V.N.Kondrat`yev;V.A.Medvedev;Ye.L.Frankevich
  19. Rev. Mod. Phys. v.32 B. Pullnam;A. Pullman
  20. J. Amer. Chem. Soc. v.92 L. E. Brown;G. A. Hamilton
  21. Bull Chem. Soc. Japan v.34 K. Fukui;K. Morokuma;T. Yonezawa
  22. J. Amer. Chem. Soc. v.90 L. Salem
  23. Nature v.213 P. Hemmerich;V.Massey;G.Weber
  24. P.S.Song
  25. Photochem. Photobiol. v.7 W.E.Kurtin;P.S. Song
  26. Acta Chem. Scand. v.21 B.Roos
  27. Tetrahedron Letters No. 15 B. Tinland
  28. Molecular Biophysics B. Pullman;B. Pullman(ed.);M. Weissbluth(ed.)
  29. Quantum Biochemistry, Interscience B.Pullman;A. Pullman
  30. Proc. Natl. Acad. Sci. U. S. v.45 B. Pullman;A. Pullman
  31. Internatl. J. Quantum Chem. v.3 P.S.Song
  32. Biopolymers Symp. No. 1 B. B. Crabe
  33. Ark. Fysik v.17 B. Grabe
  34. Biochim. Biophys. Acta v.109 J.L.Fox;K. Nishimoto;L.S.Forster
  35. J. Amer. Chem. Soc. v.63 R.S. Mulliken;C.A. Rieke;W.G. Brown
  36. J. Amer. Chem. Soc. v.72 F.A.Matsen
  37. Molecular Orbital Theory for Organic Chemists A. Streitwieser, Jr.
  38. J. Amer. Chem. Soc. v.57 G. W. Wheland;L. Pauling
  39. J. Org. Chem. v.30 F.J. Bullock;O. Jardetzky
  40. Angew. Chem. v.77 P. Hemmerich;C. Veeger;H.C.S. Wood
  41. J. Gen. Chem. (U.S.S.R.) v.28 V.M. Berozovskii;E.P.Rodinova
  42. J. Heterocyclic Chem. v.4 D.B.McCormick
  43. The Enzymes v.II H. Beinert;P.D.Boyer(ed.);H. Lardy(ed.);K.Myrback(ed.)
  44. Electronic Aspects of Biochemistry A. Ehrenberg;B. Pullnam(ed.)
  45. J. Phys. Chem. v.72 P. S. Song
  46. J. Amer. Chem. Soc. v.89 P.S.Song;W.E.Kurtin
  47. Flavins and Flavoproteins P. Kierkegaard;Norrestam;P.-E. Werner;I. Csoregh;M.von Glehn;R.Karlsson;M.Leijonmarck;O.Ronnquist;B. Stensland;O. Tillberg;L. Torbjornsson;H.Kamin(ed.)
  48. Bull. Math. Biophys. v.23 G. Karreman
  49. Biochim. Biophys. Acta v.136 J.L.Fox;S.P. Laberge;K. Nishimoto;L. S. Forster
  50. J. Chem. Phys. v.18 H. C. Longuet-Higgins
  51. Molecular Orbitals in Chemistry, Physics, and Biology I. Fischer-Hjalmars;P.-O. Lowdin(ed.);B. Pullman(ed.)
  52. Flavins and Flavoproteins A. Ehrenberg;L.E.G. Erikseon;F. Muller;E. C. Slater(ed.);C. Veeger(ed.)
  53. Biochemistry v.5 A. H. Neims;D. C. Deluca;L. Hellerman
  54. Flavins and Flavoproteins P.Hemmerich
  55. Quart. Rev. (London) v.21 G. R. Penzer;G. K. Radda
  56. Helv. Chim. Acta v.47 K.H.Dudley;A. Ehrenberg;P. Hemmerich;F. Muller