纵轴配位固载金属卟啉催化的环己烷氧化反应

由简单方法合成了ＰＶＣ,ＣＰＶＣ和Ａｌ２Ｏ３纵轴固载的氧桥连金属卟啉ＴＰＰＭ（Ⅲ）ＯＬ（Ｍ＝Ｆｅ,Ｍｎ;Ｌ＝ＰＶＣ,ＣＰＶ和ＡｌＯ３）并将它们用于温和条件下催化ＰｈＩＯ氧化环己烷的反应。实验结果表明,与未固载金属卟啉ＴＰＰＭ（Ⅲ）Ｃｌ比较,纵轴固载金属卟啉ＴＰＰＭ（Ⅲ）ＯＬ具有催化效率高,对产物的选择性强和重复使用性能好等优点。     

铁次卟啉二甲酯仿生催化α-蒎烯分子氧氧化反应

以铁次卟啉二甲酯(Fe Cl DPDME)为模型催化剂,在无任何外加溶剂及助剂的条件下,催化氧气氧化α-蒎烯,探讨了反应温度、反应时间、催化剂质量分数以及氧气流速等工艺条件对反应的影响,并对Fe卟啉催化烃类分子氧反应机理进行初步探讨。研究结果表明:氧化主要发生在α-蒎烯双键和烯丙位碳氢键,当反应温度为80℃、反应时间为6 h、催化剂质量分数为50 mg/kg、氧气流速为60 m L/min时,α-蒎烯转化率及主要氧化产物的选择性更高,分别达到17.9%和86.7%。     

金属卟啉催化性能与金属原子电子构型关系

合成了三种具有不同电子排布的金属卟啉，ＴＰＰＦｅ（Ⅲ）Ｃｌ，ＴＰＰＣｏ（Ⅱ）和［ＴＰＰＦｅ（Ⅲ）］２Ｏ，并用它们模拟细胞色素Ｐ－４５０单充氧酶在温和条件下催化环己烷的氧化反应。结果表明，金属卟啉的仿生催化性能与它们的磁场性质有关。对ＰｈＩＯ氧化环己烷的反应，具有低自旋排布的ＴＰＰＣｏ（Ⅱ）和由于反铁磁耦合而呈现抗磁性的［ＴＰＰＦｅ（Ⅲ）］２Ｏ没有催化性能，而高自旋排布的ＴＰＰＦｅ（Ⅲ）Ｃｌ具有催化     

How cultured pearls acquire their colour

Round nucleated pearls are produced through a surgical operation, where a round nucleus and a mantle tissue ‘saibo’ from donor oyster are inserted into the gonad of the host oyster. The epithelial cells in the mantle tissue proliferate around the nucleus, and thus, the pearl sac is formed. Pearl sac secrets nacre and forms a pearl. The quality and economic value of pearls are assessed by pearl features such as colour, brightness, lustre and shape. Among all these features, colour has been reported as an important economic indicator and has been widely studied by researchers. Generally, pearl colour is affected by the donor oyster which is determined genetically and biological pigments (melanin and carotenoid). Organic matrices, metal ions and other factors have also been reported to influence the colour of a cultured pearl. Recently, multi‐omics methods have been used to study the colour formation of pearl, and some key genes and signal pathways related to the colour formation of pearls have been identified. Nevertheless, the specific mechanism of pearl formation needs further research. The review combines both fresh and sea water pearls focusing on Hyriopsis cumingii and pearl oysters to provide a general overview and understanding for pearl colour formation.