Process for separation of oxygen from an oxygen containing gas using oxygen selective sorbents

A process for selectively adsorbing oxygen from a gas mixture containing oxygen which comprises contacting said gas mixture with a solid state oxygen selective material comprising at least one discrete solid state transition element complex, each said transition element complex comprising:

• a first transition element ion and one or more chelating ligands, wherein:
• i) said first transition element ion is capable of accepting intermolecular electron donation from a chelating ligand on a second discrete transition element complex;
• ii) said chelating ligand or ligands provides one to four electron donor sites To said transition element ion;
• iii) said chelating ligand or ligands provides an intermolecular electron donor site to said second transition element ion which is contained in said second discrete transition element complex;
• and
• iv) said chelating ligand or ligands contains at least one substituent that inhibits μ-peroxo dimer formation on said material;
• wherein when said material is in deoxy form, the total number of electron donor sites to said first transition element ion is five.