Structural features of sublimed layers of meso-mono-4-pyridyltriphenylporphyrinatocobalt(II) and reversible binding of molecular oxygen

The interaction of oxygen with sublimed layers of meso-monopyridyltriphenyl porphyrinatocobalt(II) (CoMPyTPP) was studied by electronic absorption and IR spectroscopy, The reversible binding Of O-2 to the axial 5-position was shown for the freshly sublimed layers: the 6-position can either be free, o r occupied by the pyridyl group of the adjacent molecule in the layer. The concentration of the complexes of the first type decreases to zero with tim e, whereas that of the second type complexes increases. The binding of oxyg en on the sublimed layers of CoMPyTPP differs substantially from that on me so-tetraphenylporphyrinatocobalt(II) and meso-tetra-3(4)-pyridylporphyrinat ocobalt(II), which loose their capability of O-2 binding with time.