EXAFS studies of organic molecular ferromagnets based on cobalt phthalocyanine: Na2.8CoPc
✍ Scribed by E. G. SHAROYAN; V. E. SHAROYAN; Ph. M. OVSYANNIKOV
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 90 KB
- Volume
- 02
- Category
- Article
- ISSN
- 1088-4246
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✦ Synopsis
Cobalt phthalocyanine (Na 2.8 CoPc) organic molecular ferromagnets with a Curie temperature higher than room temperature were synthesized. By means of EXAFS spectroscopy the nearest coordinational environment of the Co ion was examined in both Na 2.8 CoPc and pristine b-CoPc as well as in standard substances containing metallic cobalt. The nearest coordinational environment of the Co ion in ferromagnetic Na 2.8 CoPc is shown to remain virtually invariable as compared with that in pristine b-CoPc. This environment is conditioned by the nitric and carbonic coordination spheres of the phthalocyanine and differs essentially from the nearest coordinational environment of Co in metallic cobalt. The results of EXAFS studies serve as direct structural evidence that the nature of the ferromagnetism in Na 2.8 CoPc is conditioned by the organic matrix, namely by (CoPc) 2À and (CoPc) 3À anions with unpaired p-electrons in the 7e g doubly degenerate MO of the conjugated phthalocyanine macro-ring.