| Popis: |
The interaction of cobalt phthalocyanine with ammonia and oxygen in solutions of DMF was studied and the products investigated by e.s.r. Both mono- and bis-NH 3 adducts were prepared and characterized by their e.s.r. signals showing the appropriate 14 N superhyperfine (s.h.f.) splitting. Admittance of air results in the formation of the monomeric 1:1 O 2 adduct, identified by its characteristic e.s.r. signal. The thermal stability of this 1:1 O 2 adduct is surprisingly high, presumably because of the stabilizing effect of the highly polar solvent (DMF) combined with the strong Lewis base character of the axial coordinated base (NH 3 ). An irreversible loss of e.s.r. signal of the 1:1 O 2 adduct is correlated with the formation of the binuclear oxygen adduct, as found by optical spectroscopy; the rate of this reaction was shown to depend on the ammonia concentration. During the process of format on of the binuclear O 2 adduct, a narrow g ≈ 2 signal was observed, assigned to oxidation of the phthalocyanine ring to a cation radical. |
