Oxidation of manganese(II) phthalocyanine by molecular oxygen

Abstract

Manganese(II) phthalocyanine fails to react with oxygen when dissolved in rigorously purified, dry pyridine. Reaction does occur, however, in pure '', '-dimethylacetamide to yield a solution of an oxygen adduct. The reaction may be reversed slowly by degassing, more rapidly upon exposure to bright white light or upon addition of an electron donor in vacuo. Addition of certain electron donors, in oxygen, causes conversion to the known PcMnm-0-MnnlPc. This oxy-bridged species may be reconverted to the oxygen adduct by reaction with oxygen. The oxygen adduct may be isolated as a solid. Analysis, thermodynamic measurements, infrared (oxygen-18 isotopic substitution) and electronic spectra, magnetism (5 = 3/2), and ESR appear consistent with the formulation (02)MnmPc, a bound superoxide.

The synthesis and electrochemical behaviour of water soluble manganese phthalocyanines: Anion radical versus Mn(I) species

“…In MnPc complexes, the spectrum may consist of three bands corresponding to three different species in solution. This is typical of MnPc species in equilibrium in DMF and in the presence of oxygen, as suggested by Lever et al [16]. …”

Further Studies on the Oxidation State of Iron in μ-Oxo Dimeric Phthalocyanine Complexes

“…It is well known that in general for two nearly parallel phthalocyanine chromophores the Q-band is hypsochromically shifted in comparison with that for the monomer analogues (PcM or PcMX) owing to dipole-dipole exciton coupling [49,56,57,58,59,60]. Thus the Q-band has been observed at 627 nm for PyPcMn-O-MnPcPy [26,48] R is an unsubstituted or a tetra-4-tert-butyl-or tetra-4-ethylsubstituted phthalocyanine [46,[51][52][53][54][55]. Form '690' obtained either by direct reaction [8][9][10][11][12] or by reaction of iron phthalocyanine with oxygen [13][14][15] has the Qband at $690 nm (Fig.…”

Cyclic voltammetry and spectroelectrochemistry of a novel manganese phthalocyanine substituted with hexynyl groups

“…It is more enhanced upon reduction suggesting that the reduction of 3 (Fig. 2a) results in the formation of both the Mn II Pc and the MnPc μ-oxo complexes as reported before [22]. Aggregation of the complex, which might be at the origin of the unclear isosbestic point, has been ruled out since no characteristic spectral feature of the typical H aggregation of phthalocyanines appears on the spectrum.…”