New complexes of fullerences C60 and C70 with CoII and MnII tetraphenylporphyrinates and their ESR study
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Complexes of fullerenes C60 and C70 with cobalt(II) and manganese(II) tetraphenylporphyrinates of compositions Mn(TPP)·(C60)2(CS2)1.5 (1), Mn(TPP)·C70(CS2) x , wherex<=1.25 (2), Co(TPP)·C60(CS2)0.5 (3), and Co(TPP)·C70(CS2) x , wherex<0.25 (4), were synthesized and studied by ESR spectroscopy. At 77 K, complexes1 and2 have singlet ESR spectra characteristic of the low-spin (S=1/2) state of MnII, withg=2.002 and linewidths of 250 G and 300 G, respectively, and differing significantly from that of the initial MnII(TPP) (g 1=5.9 andg=2.0,S=5/2). The spectra of complexes1 and2 exposed to oxygen exhibit hyperfine structure due to interaction with55Mn and14N nuclei. The ESR spectra of complexes3 and4 are asymmetric (<g>=2.4, ΔH pp=(500–600) G), which is due to the overlap of parallel and perpendicular spectral components. The absence of ESR signals from C60 .− and C70 .− radical anions makes it possible to conclude that the formation of complexes1–4 is not accompanied by electron transfer from Co(TPP) and Mn(TPP) to fullerences C60 and C70.
Key wordsfullerenes C60 and C70 CoII tetraphenylporphyrinate and MnII tetraphenylporphyrinate synthesis ESR spectroscopy
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