Inorganic 461 lab
This experiment uses Co(salen) as a model compound illustrating the uptake of oxygen in hemoglobin. SalenH2 was prepared as the intermediate, and reacted with hydrated cobalt to prepare Co(salen). Using Co(salen) the oxygen up-take was tested. The synthesis of SalenH2 produced 0.65 g. The percent yield of salenH2 was 116% on the filter paper and 105% after transferring salenH2 to a vial. The melting point of salenH2, was 128 oC. The color of salenH2 was yellow. This was all expected from salenH2. The synthesis of Co(salen) produced 0.232 g. The percent yield of Co(salen) was 88.22% on the filter paper and 86.1 % after transferring the Co(salen) to a vial. Co(salen) was red, the active form of Co(salen). The melting point of Co(salen) was138oC. Co(salen) was able to absorb 6.83x10-5mol of O2
Why? What chemistry is taking place?
Heme proteins have been studied for years by scientists. Heme proteins contain a transition metal that can coordinate molecular oxygen. Examples of this can be found in myoglobin, hemoglobin proteins, copper containing hemocyanian and vanadium containing hemovanadin, these are all Essential for life. Myoglobin contains a porphyrin ring with an iron center .a proximal histidine group was attached directly to the iron center, and a distal histidine group on the opposite face, not bonded to the iron. In hemeoglobin, an iron held in a porphyrin ring. The porphyrin ring consists of four pyrrole molecules cyclically linked together, by methene bridges, with the iron ion bound in the center. The iron ion, which was the site of oxygen binding, coordinates with the four nitrogens in the center of the ring, which all lie in one plane. The iron bounds strongly to the globular protein via the imidazole ring of the histidine residue below the porphyrin ring. A sixth position can reversibly bind oxygen by a coordinate covalent bond, completing the octahedral