IR Study of the Interaction of Dioxygen with [meso‐Triphenyl(4‐pyridyl)porphyrinato]cobalt(II)

Abstract

The interaction of O 2 (18 O 2 ) with [meso-triphenyl(4-pyridyl)-porphyrinato]cobalt(II) [Co(MPyTPP)] has been investigated by means of IR spectroscopy under matrix-isolation conditions and by the action of dioxygen on thin sublimed layers. These studies have led to the characterisation of two dioxygen adducts: (1) a very unstable dioxygen adduct similar to that observed earlier for the closely related [mesotetraphenylporphyrinato]cobalt(II) Co(TPP), and (2) a new type of coordinated O 2 ( 18 O 2 ) complex which is formed after warming Co(MPyTPP) either in pure oxygen matrices, or as sublimed layers in the presence of oxygen. The ν(O 2 ) vibration in this second species is more than 100 cm −1 lower than

Low-Temperature Interaction of Dioxygen and Carbon Monoxide with Microporous Films of Co(II) Porphyrins Containing Bulky tert-Butyl Substituents

“…The results obtained are very close to those observed for the films of Co(II) complex of 5-(pyridin-4-yl)-10,15,20-triphenylporphyrin (Co(M4PyTPP)) [18,19] and explained in terms of formation of coordinatively linked oligomers and formation of a six-coordinate dioxygen adduct with the pyridyl base in the trans axial position. The same pattern was observed upon interaction of O 2 with sublimed layers of Fe(M4PyTPP).…”

Interaction of diatomic ligands with Fe(II) meso-mono-4-pyridyl-tri-phenyl-porphyrinate. Spectral evidence of self-assembly in sublimed layers

“…This model is supported by recent studies in connection with CoMPyTPP sublimed layers [29]. These layers conserve both microporosity and low-temperature O 2 -binding ability over a period of several months upon storing at ambient conditions.…”

“…This is very close to value of the lower frequency band observed in this work. However, it should be noted that in these cases of iron-porphyrins the changes in ν(O 2 ) upon coordination of axial nitrogen bases are significantly less than for Co(II) analogues [28,29] and additional evidence for these conclusions, from electronic absorption spectra for example, would be desirable.…”

Interaction of dioxygen with nitrosyl complexes of meso-mono-4(3)-pyridyl-triphenylporphyrinato cobalt in sublimed layers

“…In contrast to metal complexes of meso-tetraarylporphyrins, sublimed layers of meso-pyridyl substituted derivatives with metal ion capable of axial coordination retain a microporous structure and the ability of reversible coordination of various ligands during storage. [2,3] This is due to the formation of zigzag type oligomeric structures by coordinating pyridyl group of one molecule with the metal ion of the adjacent molecule in the layer. For complexes with metals prone to octahedral coordination, such supramolecular organization leads to the formation of a penta-or hexacoordinated complexes.…”

“…For complexes with metals prone to octahedral coordination, such supramolecular organization leads to the formation of a penta-or hexacoordinated complexes. [2][3][4][5] Nitrosyl complexes of metalloporphyrins are of considerable interest in biology and in medicine as potential sources of NO. [6] It has been previously shown, [4] that the reaction of NO with sublimed layers of I and II leads to the formation of two types of nitrosyl complexes: pentacoordinated -with molecules at the end of the oligomers and those not involved in the oligomeric structures; and hexacoordinated -with the sixth coordination site occupied by the pyridyl group of adjacent molecule in the layer.…”