Hybrid organic-inorganic silica materials containing organic functional groups have been preparedby the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane...Hybrid organic-inorganic silica materials containing organic functional groups have been preparedby the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane. The hybrid silica was further modified by organic compounds having abifunctional group. These modified hybrid silicas were used as catalysts for various nucleophilic reactions.And also, these were complexed with metallic ions for use as catalysts for oxygen oxidation of hydrocarbons.展开更多
Here,we report the nitric oxide dioxygenation(NOD)reactions of Ni^(III)-peroxo,[(12-TMC)Ni^(III)(O_(2)^(2-))]^(+)(Ni^(III)-O_(2)^(2-),1),and Co^(III)-peroxo,[(12-TMC)Co^(III)(O_(2)^(2-))]^(+)(Co^(III)-O_(2)^(2-),2),co...Here,we report the nitric oxide dioxygenation(NOD)reactions of Ni^(III)-peroxo,[(12-TMC)Ni^(III)(O_(2)^(2-))]^(+)(Ni^(III)-O_(2)^(2-),1),and Co^(III)-peroxo,[(12-TMC)Co^(III)(O_(2)^(2-))]^(+)(Co^(III)-O_(2)^(2-),2),complexes bearing N-tetramethylated cyclam(TMC)ligands.The reaction of complex 1 with nitric oxide(NO)generates Ni^(II)-nitrato complex[(12-TMC)Ni^(II)(NO_(3)^(-))]^(+)(Ni^(II)-NO_(3)^(-),3).However,in contrast to the NOD reaction of 1,compound 2 produces Co^(II)-nitrito complex,[(12-TMC)Co^(II)(NO_(2)^(-))]^(+)(Co^(II)-NO_(2)^(-),4),with O_(2)gas formation.Results suggested the formation of a presumptive Ni-peroxynitrite([Ni-PN]^(+),[Ni-ONOO^(-)]^(+))intermediate,in the NOD reaction of 1,prior to the generation of Ni^(II)-NO_(3)^(-)(3).Although the end product of the reaction of 2 with NO is different from that of 1,the mechanistic study explored by using 2,4-di-tert-butylphenol(2,4-DTBP)suggested that the reaction of 2 with NO also occurs via a presumed Co-peroxynitrite([Co-PN]^(+),[Co-ONOO^(-)]^(+))intermediate.Furthermore,exploring these NOD reactions and tracking the oxygen atom using 18O-labeled hydrogen peroxide(H_(2)^(18)O_(2))revealed that two oxygen atoms of 3(Ni^(II)-18O_(2)N^(16)O^(-))and one oxygen atom of 4(Co^(II)-18ON^(16)O^(-))are derived from the peroxo(O_(2)^(2-))moieties of 1 and 2,respectively.Furthermore,we have explored the M-peroxo regeneration from NOD products(3 and 4),and for the first time,we have observed the formation of M^(III)-O_(2)^(2-)complexes,1 and 2,upon treatment with H_(2)O_(2)and triethylamine(TEA),respectively.This work is the first-ever report which showed the exact NO dioxygenase(NOD)enzyme catalytic cycle.Furthermore,we have also explored the NO activation of 3 and 4,and surprisingly,we observed the formation of Co-nitrosyl(5)from 4 upon reaction with NO;in contrast,3 was unreactive towards NO.Evidence supporting the formation of[Ni-PN]^(+)and[Co-PN]^(+)intermediates is also presented.展开更多
文摘Hybrid organic-inorganic silica materials containing organic functional groups have been preparedby the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane. The hybrid silica was further modified by organic compounds having abifunctional group. These modified hybrid silicas were used as catalysts for various nucleophilic reactions.And also, these were complexed with metallic ions for use as catalysts for oxygen oxidation of hydrocarbons.
文摘Here,we report the nitric oxide dioxygenation(NOD)reactions of Ni^(III)-peroxo,[(12-TMC)Ni^(III)(O_(2)^(2-))]^(+)(Ni^(III)-O_(2)^(2-),1),and Co^(III)-peroxo,[(12-TMC)Co^(III)(O_(2)^(2-))]^(+)(Co^(III)-O_(2)^(2-),2),complexes bearing N-tetramethylated cyclam(TMC)ligands.The reaction of complex 1 with nitric oxide(NO)generates Ni^(II)-nitrato complex[(12-TMC)Ni^(II)(NO_(3)^(-))]^(+)(Ni^(II)-NO_(3)^(-),3).However,in contrast to the NOD reaction of 1,compound 2 produces Co^(II)-nitrito complex,[(12-TMC)Co^(II)(NO_(2)^(-))]^(+)(Co^(II)-NO_(2)^(-),4),with O_(2)gas formation.Results suggested the formation of a presumptive Ni-peroxynitrite([Ni-PN]^(+),[Ni-ONOO^(-)]^(+))intermediate,in the NOD reaction of 1,prior to the generation of Ni^(II)-NO_(3)^(-)(3).Although the end product of the reaction of 2 with NO is different from that of 1,the mechanistic study explored by using 2,4-di-tert-butylphenol(2,4-DTBP)suggested that the reaction of 2 with NO also occurs via a presumed Co-peroxynitrite([Co-PN]^(+),[Co-ONOO^(-)]^(+))intermediate.Furthermore,exploring these NOD reactions and tracking the oxygen atom using 18O-labeled hydrogen peroxide(H_(2)^(18)O_(2))revealed that two oxygen atoms of 3(Ni^(II)-18O_(2)N^(16)O^(-))and one oxygen atom of 4(Co^(II)-18ON^(16)O^(-))are derived from the peroxo(O_(2)^(2-))moieties of 1 and 2,respectively.Furthermore,we have explored the M-peroxo regeneration from NOD products(3 and 4),and for the first time,we have observed the formation of M^(III)-O_(2)^(2-)complexes,1 and 2,upon treatment with H_(2)O_(2)and triethylamine(TEA),respectively.This work is the first-ever report which showed the exact NO dioxygenase(NOD)enzyme catalytic cycle.Furthermore,we have also explored the NO activation of 3 and 4,and surprisingly,we observed the formation of Co-nitrosyl(5)from 4 upon reaction with NO;in contrast,3 was unreactive towards NO.Evidence supporting the formation of[Ni-PN]^(+)and[Co-PN]^(+)intermediates is also presented.
