If you need an accessible version of this item please contact JSTOR User Support

A Magnetic Resonance Study of Metal-Porphyrin/Caffeine Complexes

C. D. Barry, H. A. O. Hill, P. J. Sadler and R. J. P. Williams
Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences
Vol. 334, No. 1599 (Sep. 25, 1973), pp. 493-504
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/78340
Page Count: 12
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
A Magnetic Resonance Study of Metal-Porphyrin/Caffeine Complexes
Preview not available

Abstract

The effects are described of MnIII, FeIII, CoII, NiII, CuII and AgII porphyrins on the chemical shifts and linewidths of the proton resonances of caffeine, and of caffeine on the electron paramagnetic resonance spectra of CoII, CuII and AgII porphyrins in chloroform solution. The largest n.m.r. shifts are produced by divalent ions with the largest g tensor anisotropy, and trivalent ions with the largest zero-field splittings; metal porphyrins with the largest effective magnetic moments produce the most broadening of the resonances. The n.m.r. and e.p.r. effects are interpreted as arising from molecular complex formation between caffeine and the metal porphyrins. An attempt is made to relate the observed dipolar n.m.r. shifts and broadenings for CoII porphyrin-caffeine to the structure of the complex in solution. Acceptable structures were of the plane-to-plane type, with the metal situated above N9 of the five membered ring.

Page Thumbnails

  • Thumbnail: Page 
493
    493
  • Thumbnail: Page 
494
    494
  • Thumbnail: Page 
495
    495
  • Thumbnail: Page 
496
    496
  • Thumbnail: Page 
497
    497
  • Thumbnail: Page 
498
    498
  • Thumbnail: Page 
499
    499
  • Thumbnail: Page 
500
    500
  • Thumbnail: Page 
501
    501
  • Thumbnail: Page 
502
    502
  • Thumbnail: Page 
503
    503
  • Thumbnail: Page 
504
    504