Using Fe6(OH)18(H2O)6 as a ring cluster model for superparamagnetic iron oxide nanoparticles, noncovalent configurations and three mechanisms of covalent functionalization of superparamagnetic iron oxide nanoparticles with cyclophosphamide an anticancer drug were studied. Quantum molecular descriptors, solvation, and binding energies of noncovalent interactions were investigated the in gas and solution phases at the B3LYP and M06-2X density functional levels. In the vicinity of superparamagnetic iron oxide nanoparticles, the reactivity of the drug increases, showing cyclophosphamide can probably bind to superparamagnetic iron oxide nanoparticles through Cl (k1 mechanism), P=O (k2 mechanism), and NH in a six-membered ring (k3 mechanism) groups. The activation parameters of all pathways were calculated, indicating the high barriers related to the k1 and k2 mechanisms are higher the barrier related to the k3 mechanism. The k3 mechanism is also spontaneous and exothermic and is therefore the preferred mechanism for covalent functionalization.

中文翻译：

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超顺磁性氧化铁纳米颗粒作为环磷酰胺抗癌药物纳米载体的力学和能量研究：量子力学方法

使用 Fe6(OH)18(H2O)6 作为超顺磁性氧化铁纳米颗粒的环簇模型，研究了超顺磁性氧化铁纳米颗粒与抗癌药物环磷酰胺的非共价构型和共价官能化的三种机制。在 B3LYP 和 M06-2X 密度泛函水平上研究了气相和溶液相中的量子分子描述符、溶剂化和非共价相互作用的结合能。在超顺磁性氧化铁纳米粒子附近，药物的反应性增加，表明环磷酰胺可能通过六元环中的Cl（k1机制）、P=O（k2机制）和NH与超顺磁性氧化铁纳米粒子结合。 k3 机制）组。计算所有途径的激活参数，表明与 k1 和 k2 机制相关的高壁垒高于与 k3 机制相关的壁垒。k3 机制也是自发和放热的，因此是共价功能化的首选机制。