Studies On The Syntheses And Properties Of Radical Compounds Containing Non-metal(Nitrogen,Oxygen,Phosphorus) And Metal(Ruthenium,Osmium)

Free radicals are atoms,molecules or ions that have unpaired electrons.Radicals usually have short lifetime and high activities because of the unpaired electron.Stable radicals not only deepen people’s understanding of the structural chemistry,but also have important practical applications in materials science,biomedicine and other fields;It can be used as spin labels,radical scavengers and battery filling materials,and can also be applied as magnetic materials and superconducting materials.The practical value of radicals prompted people to find more stable free radicals,and then how to stabilize radicals is the focus of radical chemistry.We have stabilized radical compounds containing nitrogen,oxygen,phosphorus,ruthenium and osmium by introducing weakly coordinating anions and increasing steric hindrance,and studied their structures and properties.The main work are introduced as the following four parts in this paper.1.A series of of bis(triarylamine)dications 12+-42+ were successfully isolated with long bridging groups by using weakly coordinating anions and the bridging groups were bithienyl and biphenyl.Their geometries and electronic structures have been fully characterized by single-crystal X-ray diffraction,EPR,SQUID and UV-Vis absorption spectroscopy,in conjunction with theoretical calculatios.Dication 12+ is closed-shell singlet in the ground state,and 22+-42+ are diradical dications featuring open-shell singlet ground states.22+ has a weaker diradical character relatively to 32+-42+ and larger singlet-triplet energy gap.Moreover dications 32+and 42+can be thermally excited to triplet states at room temperature with rather small singlet-triplet energy gap.The structure and magnetic properties of the compounds 12+-42+ have changed significantly with the changes in the bridging groups and the phenyl substituents.2.The radical cation 6·+ and diradical dication 62+of heteronuclear tetraaryl-iminophosphane were synthesized.Their electronic structures and geometries have been characterized by EPR spectroscopy,in conjunction with theoretical calculations.The spin density of 6·+ is mainly localized on nitrogen and its connected benzene ring,which is different from the reported cation of carbene-stabilized phosphorus mononitride.Dication 62 has an open-shell singlet ground state.3.We successfully synthesized a series of tert-butyl nitroxides 7-8 centered on heavier atoms of nitrogen group,and isolated radical cation of compound 7.These compounds were characterized by various methods.Both of 7 and 8 exhibit doublet ground states,which were easily excited to quartet states.Morever,compound 8 could be considered as triradical with a degenerate doublet state and quartet state.Phase transition was observed in the SQUID measurements for the powder of 7.Radical cation 7·+ has an open-shell singlet ground state,which thermally can be excited to triplet state.4.Radical cations of diruthenium 9·+,diosmium 10·+ were isolated and structurally characterized.The EPR spectroscopy and theoretical calculations indicate that the spin density mainly resides on ligands.The X-ray structure shows that the change of metal-metal bond length is negligible upon one-electron oxidation.Sp3 C-H bond activation was observed during the reaction of parent molecule with the trityl cation,which afforded a cationic tetramethylfulvene complex[9-H]+and[10-H]+.