Ethylene-propylene rubber （EPR） graft copolymers were prepared successfully by anionic coupling technique between chlorinated EPR （C1-EPR） and living anionic polystyrene chain. The EPR-g-styrene was characterized ...Ethylene-propylene rubber （EPR） graft copolymers were prepared successfully by anionic coupling technique between chlorinated EPR （C1-EPR） and living anionic polystyrene chain. The EPR-g-styrene was characterized by hydrogen nuclear magnetic resonance （1H NMR） and gel penetration chromatogram （GPC）.展开更多
A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel- lent yield. In contrast, the ex...A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel- lent yield. In contrast, the expected nucleophilic photo-S_(RN) 1 substitution originating from the carb- anion was observed in the case of t-butyl propionate. According to the proposed mechanisms and MO correlation diagrams of the coupling step of nucleophiles with aryl radical, the interesting con- trast is reasonably attributed to the variation in energy gap between π~*c-o and π~*Ar of (ArNu)- Usually, the odd electron of (ArNu)- is weightly populated at π~*c-o, however, the diminished priv- ilege of π~*c-o in menthyl propionate promotes a dominant population of the odd electron at π~*Ar, which leads to the fragmentation of (ArNu)- into the starting carbanion and aryl radical.展开更多
文摘Ethylene-propylene rubber （EPR） graft copolymers were prepared successfully by anionic coupling technique between chlorinated EPR （C1-EPR） and living anionic polystyrene chain. The EPR-g-styrene was characterized by hydrogen nuclear magnetic resonance （1H NMR） and gel penetration chromatogram （GPC）.
基金the National Natural Science Foundation of China.
文摘A competitive coupling of amide anion over menthyl propionate anion with aryl radical in photo-S_(RN) 1 mechanism was encountered. The rcaction afforded N-aryl propionic amide in excel- lent yield. In contrast, the expected nucleophilic photo-S_(RN) 1 substitution originating from the carb- anion was observed in the case of t-butyl propionate. According to the proposed mechanisms and MO correlation diagrams of the coupling step of nucleophiles with aryl radical, the interesting con- trast is reasonably attributed to the variation in energy gap between π~*c-o and π~*Ar of (ArNu)- Usually, the odd electron of (ArNu)- is weightly populated at π~*c-o, however, the diminished priv- ilege of π~*c-o in menthyl propionate promotes a dominant population of the odd electron at π~*Ar, which leads to the fragmentation of (ArNu)- into the starting carbanion and aryl radical.
