Iron Porphyrin Complexes Anchored to a Polymeric Core-Shell Nanosphere

Abstract

The iron porphyrin catalyst was bonded coordinately to the temperature sensitive nanosphere with core-shell structure to prepare the easily recoverable heterogeneous catalyst with temperature responsiveness. The average size of iron porphyrin bound core-shell nanosphere was 470 nm. Binding of the porphyrin was observed by the UV-VIS spectroscopy, fluorescence-activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM), elctron paramagnetic resonance (EPR) spectometer. Scanning electron microscopy (SEM) images showed that iron porphyrin bound core-shell nanospheres were spherical and monodispersed. Under the current oxidation condition, the cyclohexene epoxide was a dominant product. Through this study, we found that the iron porphyrin bound core-shell nanosphere has the thermosensitivity, and the optimal reaction solvent composition of acetonitrile/ water. In addition, iron porphyrin bound core-shell nanosphere could be recovered by centrifugation and its activity was maintained more than the third cycle.;온도에 민감하고 회수가 쉬운 불균일 촉매를 만들기 위하여 Iron porphyrin 촉매를 온도 민감성 core-shell 구조 nanosphere에 배위 결합 시켰다. Iron porphyrin bound core-shell nanosphere의 평균 지름은 약 480 nm 였다. Iron porphyrin의 binding 여부는 UV-VIS spectrophoto ?meter와 fluorescence-activated cell sorting (FACS), confocal laser scanning microscopy (CLSM), electron paramagnetic resonance (EPR) spectrometer로 관찰하였다. Scanning electron microscopy (SEM)으로 관찰한 core particle과 core-shell nanosphere, iron porphyrin bound core-shell nanosphere는 모두 둥근 형태를 가지고 있었으며 크기가 비교적 균일했다. 이번 실험에서 행해진 산화 조건에서는 cyclohexene epoxide가 주된 생성물이었다. Iron porphyrin bound core-shell nanosphere는 온도 민감성을 가져서 수용액 상에서 iodosylbenzene (PhIO)으로 수용액에서 cyclohexene oxidation 반응을 하였을 때 lower critical solution temperature (LCST) 근처에서 반응성이 가장 좋았고, 용매에 의한 영향도 받아서 acetonitrile/물 조성이 50/50일 때 cyclohexene oxidation 반응성이 가장 좋았다. 게다가 iron porphyrin bound core-shell nanosphere는 원심 분리에 의하여 쉽게 회수할 수 있었고, 세 번의 재생 실험 까지 반응성을 크게 잃지 않았다.