Quantum chemical investigations of lanthanoid(III) and actinoid(III) texaphyrin complexes as well as of their medical and technical applications

镧系元素（III）和锕系元素（III）配合物的大环texaphyrin配体将通过量子化学方法进行研究，即使用密度泛函和二阶Moeller-Plesset微扰理论进行结构优化，以及在增量方案的框架内使用单、双和摄动三元组的耦合簇ansatz进行单点计算，以校准（相对）能量。重镧系元素和锕系元素将分别用标量相对论性的4f-in-core和5f-in-core赝势来处理，并且为了校准的目的，也用相应的4f-in- valence赝势和5f-in-valence赝势来处理，以及在相对论性的全电子水平上使用二阶道格拉斯-克罗-赫斯哈密顿量。将应用至少为价-三zeta质量的基集。该研究的主要目标是进一步了解镧系（III） texaphyrin复合物医疗应用的机理细节，并澄清是否存在相应的锕系（III）系统，以及它们是否可能在镧系元素与锕系元素的分离中发挥作用，例如在核废料清理过程中。镧系（III） texaphyrin复合物，特别是Gd和Lu的复合物，在临床试验中作为实验药物进行研究，例如作为x射线放射治疗的肿瘤选择性催化剂和肿瘤光动力治疗的光敏剂。计划中的计算将确定它们的结构和稳定性，以及它们在医学应用中的重要特性，例如它们在人体所谓的治疗窗口波长区域的吸收光谱（用于辐射到达体内所需的目标），单线态-三重态分裂（用于直接激活分子氧）和氧化还原电位（用于参与活性氧的生成）。中心金属的作用，侧链以及pi-电子系统的大小对这些性质的有利调整将被研究。从氧和/或水开始，由镧系（III） texaphyrin络合物催化生成活性氧的机理将被计算。将研究抗坏血酸和l -抗坏血酸（维生素C）的其他衍生物在这些反应中的作用。为了比较抗坏血酸的氧化，不存在镧系（III） texaphyrin络合物作为催化剂将进行研究。锕系（III） texaphyrin复合物迄今在实验上未知，很可能是由于锕系元素的放射性所引起的困难。将研究它们的结构和稳定性，并讨论它们在镧系(III)-锕系（III）分离过程中的可能用途。实验上已知的放线菌基texaphyrin复合物也将被考虑。

Lanthanide(III) and actinide(III) complexes of the macrocyclic texaphyrin ligand will be studied by quantum chemical methods, i.e., with structure optimizations using density functional and second-order Moeller-Plesset perturbation theory, as well as with single-point calculations using the coupled-cluster ansatz with singles, doubles and perturbative triples in the framework of the incremental scheme in order to calibrate the (relative) energies. The heavy lanthanide and actinide elements will be treated with scalar-relativistic 4f-in-core and 5f-in-core pseudopotentials, respectively, and for calibration purposes also with corresponding 4f- and 5f-in-valence pseudopotentials as well as at the relativistic all-electron level using the second-order Douglas-Kroll-Hess Hamiltonian. Basis sets of at least valence-triple-zeta quality will be applied. The main goal of the study is to gain more insight in mechanistic details of medical applications of lanthanide(III) texaphyrin complexes as well as to clarify if corresponding actinide(III) systems exist and if they might play a role for the separation of lanthanides from actinides, e.g., during the clean-up of nuclear waste.Lanthanide(III) texaphyrin complexes, especially those of Gd and Lu, are investigated as experimental drugs in clinical trials, e.g., as tumor-selective catalysts in X-ray radiation therapy and photosensitizers for photodynamic therapy for oncology. The planned calculations will determine their structures and stabilities, as well as important properties for their medical applications such as their absorption spectra in the wavelength region of the human body's so-called therapeutic window (for the radiation reaching the desired target in the body), singlet-triplet splittings (for direct activation molecular oxygen) and redox potentials (for participating in the generation of reactive oxygen species). The role of the central metal, the side chains as well as the size of the pi-electron system for a favorable tuning of these properties will be investigated. The mechanism of the generation of reactive oxygen species, starting from oxygen and/or water, catalyzed by lanthanide(III) texaphyrin complexes will be calculated. The role of ascorbate and other derivatives of L-ascorbic acid (vitamin C) in these reactions will be studied. For comparison the oxidation of ascorbate without presence of a lanthanide(III) texaphyrin complex as a catalyst will be investigated.Actinide(III) texaphyrin complexes are so far unknown experimentally, most likely due to the difficulties arising form their radioactivity of the actinides. Their structures and stabilities will be investigated and their possible usefulness in lanthanide(III)-actinide(III) separation processes will be addressed. The experimentally known actinyl texaphyrin complexes will also be considered.