Electrospray Ionization Mass Spectrometry And Acid Dissociation Study On The Polyamine Cobalt Complexes With Dioxygen

Both synthetic and natural complexes which can reversibly bind dioxygen are termed oxygen carrier. Due to high molecular weights and complicated structures of natural oxygen carriers such as hemoglobin, myoglobin, the oxygen-uptake mechanism studies were very difficult. Polyamine cobalt complexes with small molecular weights and simple structures, can be served as a model compound of oxygen carriers to be investigated. polyamine complexes synthesized by Solid-phase reaction have high oxygen-uptake performance than liquid-phase products. Furthermore, the intermediate products can be acquired for the long oxygenation time which are helpful to study oxygenation mechanism.This article is mainly as follows:(1) In preface, the study background and significance of oxygen carrier were reviewed, and research progress and methods of polyamine complexes were discussed.(2) A series of solid polyamine cobalt complexes were prepared by solid-phase reaction at room temperature, and their performance of oxygen-absorption at different temperatures were tested. Oxygenation products were characterized by TG-DSC, IR, UV-vis. The changes of -NH2 of polyamine complexes were determined by formol-titration method, and moisture content in reaction system was measured by Karl-Fischer method.(3) Oxygenation complexes of cobalt-dien obtained at different reaction temperatures and time were studied by ESI-MS. Existing forms of complexes ions and their production pathways in ESI-MS were investigated, and oxygenation species of cobalt-dien in different reaction conditions were proposed.(4) Oxygenation complexes of cobalt-trien obtained at different reaction temperatures and time were studied by ESI-MS. Existing forms of complexes ions and their production pathways in ESI-MS were investigated, and oxygenation species of cobalt-trien in different reaction conditions were proposed. (5) Acid dissociation of both non-oxygenated and oxygenated cobalt-trien complexes were performed and free cobalt ion and ligand in dissociation solution were separated using cation exchange column. For the acid eluent, cobalt ion content was tested by atomic absorption and ligand content were determined by the Kjeldahl method. Non-dissociated complexes were characterized by ESI-MS and dissociated ligands by GC-MS.(6) Based on ESI-MS results, combining with other experimental results, the coordination behaviors of cobalt with polyamine were investigated and oxygenation and oxidation mechanism of polyamine complexes were proposed.