Metal complex oxygen absorbents

NEW METAL COMPLEX OXYGEN ABSORBENTS FOR THE RECOVERY OF OXYGEN... 

Hexaalkoxides are only known for the two elements tungsten and uranium. In both cases, physical and spectroscopic data are consistent with monomeric, octahedral complexes. Tungsten hexaalkoxides are pale yellow or colorless substances that readily sublime and exhibit the expected H NMR and mass spectra.189 The totally symmetric v(W—O) stretch occurs between 530 and 600 cm-1 in the IR spectrum, depending on the alkyl substituents. In contrast, the homoleptic phenoxide W(OPh)6 is intense red in color due to the presence of a strong oxygen-to-metal charge transfer band in this d° complex which absorbs in the visible part of the spectrum.36... 

One of the typical chemical characteristics of metal ions and/or their complexes is their ability to bind specifically and reversibly with small molecules, such as alkene, carbon monoxide, molecular nitrogen, and moleeular oxygen [1-3]. For instance, ethylene coordinatively binds with silver or copper ions, and molecular oxygen with metalloporphyrins. When such metal ions or metalloporphyrins are molecularly bound in macromolecules to form metal complexes, the reversible binding of small molecules with the metal complexes in macromolecules offers extensive potential applications, such as separation membranes, absorbents, and sensors. 

Many transition metal complexes form adducts with molecular oxygen. Those that combine reversibly with O2 are designated as oxygen carriers adducts in which O2 is absorbed irreversibly are also known. Here, we shall provide increased-valence descriptions for some reversible Fe(ll) and Co(ll) dioxygenyl addncts, thereby contrasting different formulations for the oxidation state of the metal ion that have been proposed for these types of complexes. 

Using ideas of subtractive color mixing, we ascertained the wavelength components of white light that the complex cation absorbs. The broadness of the absorption band is due to vibrations in the metal to oxygen bonds. By using the maximum of the absorption curve, we calculated the most probable energy of the absorbed photons. 

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