The Reactivity Of A Tricyano Os(Ⅵ) Nitrido Complex Based On The N Atom Transfer

To study the reaction mechanism of the nitrogen fixation cycle in biological nitrogenases,many high-valent transition metal nitride complexes have been synthesized.With more and more metal nitrido complexes have been reported,M≡N is widely used in the fields of synthesis and catalysis;Among the many studies on the reactivity of transition metal nitrido complexes,the study of osmium nitride complexes is one of the earliest and deepest metal nitrogen complexes.This thesis have investigated the interaction of（PPh₄）[Os^Ⅵ（N）（L）（CN）³]（OsN,HL=2-（2-hydroxy-4-nitrophenyl）benzoxazole）with various unsaturated hydrocarbons and ketones;The reactivity of OsN in the excited state and the thermodynamic reaction in the ground state were discussed,and totally 11 novel Os complexes were synthesized.The photochemical reaction afforded three Os（Ⅵ）complexes containing various aniline ligands,one Os（Ⅵ）complexes containing aziridine ligands,one Os（Ⅵ）complex containing azavinyl ligands and an Os（Ⅱ）complex with a diazonium ligand.In the ground state,three Os（Ⅲ）complexes with amidine ligands and one Os（Ⅲ）complex with guanidinium ligands were obtained.the crystal structrues of four Os complexes have been determined by X-ray crystallography.All the complexes have been further characterized by ¹H-NMR,ESI/MS and satisfied CHN analysis.Upon irradiation by blue light（λ>460 nm）,OsN in the excited state reacted with1,3-cyclohexadiene,1,4-cyclohexadiene,1,2-dihydronaphthalene,1,2,3,4,5-pentamethylcyclopentadiene,2,3-dimethyl-2-butene,cis/trans-1,2-stilbene and 1,3-diphenylisobenzofuranafforded（PPh₄）[Os^Ⅳ（L）（CN）₃（NHPh）]（（PPh₄）1）,（PPh₄）[Os^Ⅳ（L）（CN）₃（NH-NAPH）]（（PPh₄）2）,（PPh₄）[Os^Ⅳ（L）（CN）₃（NH-Me₅Cp）]（（PPh₄）3）,（PPh₄）[Os^Ⅳ（L）（CN）₃(Az_（-H）]（（PPh₄）4）（Az=2,2,3,3-tetramethylaziridine）,（PPh₄）[Os^Ⅲ（L）（CN）₃（N=（Sb）-OMe）]（（PPh₄）5）（PPh₄）[Os^Ⅳ（L）（CN）₃（=N=C[Ph][2-PhCOC₆H₄]）]（（PPh₄）6）,respectively;the photoreaction of OsN with 2,4,6-trimethylaniline（Me₃An）in degassed acetone solution afforded（PPh₄）[Os^Ⅱ（L）（CN）₃（N≡NPhMe₃）]（（PPh₄）7）;After addition of aniline（An）or Me₃An in the ground state,OsN reacted with acetone,2-butanone,and acetophenone to give（PPh₄）[Os^Ⅲ（L）（CN）₃（L¹）](（PPh₄）8,L¹=NH=C（NH-Ph Me₃）（C（=NPhMe₃）（CH₃））,（PPh₄）[Os^Ⅲ（L）（CN）₃（L²）]（（PPh₄）9,L²=NH=C（NH-Ph Me₃）（C（=NPhMe₃）Ph））,（PPh₄）[Os^Ⅲ（L）（CN）₃（L³）]（（PPh₄）10,L³=1,3-Diphenylguanidine）,（PPh₄）[Os^Ⅲ（L）（CN）₃（L⁴）]（（PPh₄）11,L⁴=N-phenylethylimine）,respectively.Through a series of experiments,we compared and analysed the differences in the reactivity of OsN^*to unsaturated hydrocarbons with different structures in the excited state.In other words,there are different pathways for N atom transfer reactions.OsN^*exhibits strong H atom abstraction ability for activeα-C-H bonds in unsaturated hydrocarbons and strong electrophilic reactivity for unsaturated hydrocarbons without activeα-C-H bonds;The reactivity of OsN in the ground state with various ketones are very similar,but the products were affected by the steric hindrance and the stability of the carbanion,which could be validated by their structure.