To reveal reaction mechanism of PS-II, the reaction products of photolysis may be compared with their thermolytic products. According to required molecular assemblies in manganese clusters at WOC of PS-II, we have strategically synthesized dimers (M-1, M-2), trimers (M-3A, M-3B) and tetramer (M-4) using spin carrier imino-phenol functionalized ligands viz. Lawsone Oxime (L-1) and Phthiocol Oxime (L-2) of naturally occurring quinones .These are characterized by elemental analyses, thermogravimetric analyses, differential thermal analyses, powder X-ray diffraction and infrared spectroscopy. Stabilization energies for molecular associations of ligands in various redox and stereoisomeric forms via hydrogen bondings are compared with thermal energies required for their expulsion from the coordination polymers calculated with the help of Coats and Redfern’s relation of rising temperatures. Activation energy required for establishing tetramer (M-4) and dimer (M-2) in coordination sphere by counter ion using same synthetic route is found to be comparable (~37.48±1 kJ mol-1). Quantitized energies from TG-DTA data for valence tautomers of redox active ligands play significant role in formation of resultant model compound. viz. tetramer, dimer of dimer and trimer. The role of oxo, acetato and spin carrier ligands in model cluster compounds are proposed with respect to their expulsion energies.
为了揭示 PS-II 的反应机制,可以将光解反应产物与其热解产物进行比较。根据 PS-II 的 WOC
锰簇所需的分子组装,我们使用自旋载体亚
氨基苯酚功能化
配体,即 Lawsone Oxime(L-1)和 Phthiocol Oxime(
L-2),有策略地合成了二聚体(M-1、M-2)、三聚体(M-3A、M-3B)和四聚体(
M-4)。通过元素分析、热重分析、差热分析、粉末 X 射线衍射和红外光谱分析对这些
配体进行了表征。通过氢键将各种氧化还原形式和立体异构形式的
配体与分子结合的稳定能量与借助 Coats 和 Redfern 的升温关系计算出的配位聚合物将
配体排出所需的热能进行了比较。结果发现,采用相同的合成路线,通过反离子在配位层中建立四聚体(
M-4)和二聚体(M-2)所需的活化能相当(~37.48±1 kJ moL-1)。从 TG-DTA 数据中得到的氧化还原活性
配体价态同系物的定量能量在生成模型化合物(即四聚体、二聚体的二聚体和三聚体)的过程中发挥了重要作用。根据氧化、乙酰和自旋载体
配体的驱逐能,提出了它们在模型团簇化合物中的作用。