Coordination of 1,3-bis(diphenylphosphinomethyl)benzene and 1,3-bis(ditert butylphosphinomethyl)benzene to uranyl nitrate
This thesis presents the results of coordination reactions an actinide polyatomic cation with pincer type phosphine ligands. Pincer ligands are known to generate useful catalysts when complexed with metal ion. Complexation studies of uranyl ion, in a non-aqueous medium can reveal valuable information towards their utilization as catalysts. With that intention we have studied the complexation nature of PCP type pincer ligands 1,3 - bis (diphenylphosphinomethyl)benzene and 1,3- bis (ditertbutylphosphinomethyl)benzene with nonradioactive uranyl nitrate in non-aqueous medium. The photo reaction of uranyl nitrate with PCP type ligand 1,3 - bis (diphenylphosphinomethyl) benzene and 1,3- bis (ditertbutylphosphinomethyl)benzene in tetrahydrofuran (THF) and atmospheric condition yields different kind of products. When uranyl nitrate is treated with 1,3-bis (diphenylphosphinomethyl)benzene in such condition a one dimensional coordination polymer 4 is formed. In contrast, the treatment of uranyl nitrate in similar conditions with 1,3-bis(ditertbutylphosphinomethyl)benzene yields a dinuclear complex 5. In both of these complexes the phosphorous atoms of the ligands were found to be oxidized. Both the phosphorus atoms of the ligand in compound 4 are converted to phosphinoxides which coordinates to a uranium center. On the contrary, the phosphorus atoms of the ligand in compound 5 have been unevenly oxidized. One of the phosphorus atoms converted to phosphinoxide, which coordinates to a uranium atom. The other phosphorus atom is converted to phosphinate. Two oxygen atoms of the phosphinate moiety bridge between two uranium atoms. One of the phosphorus-oxygen bonds in the ligand of compound 5 is single bond and the other one is a double bond as in case of 4. The single bonded oxygen of the phosphorus-oxygen moiety is anionic and the double bonded oxygen is neutral. As the phosphorus atom was oxidized to phosphinate anion, it caused the loss of one tertiary butyl group on the phosphorus atom. Because of this anionic coordination one of the nitrate anion of each uranyl nitrate is eliminated. As a result both uranyl atom remain in +VI oxidation state.
"Coordination of 1,3-bis(diphenylphosphinomethyl)benzene and 1,3-bis(ditert butylphosphinomethyl)benzene to uranyl nitrate"
ETD Collection for Tennessee State University.