WATER SOLUBLE OCTANUCLEAR IRON III CLUSTERS AS MRI CONTRAST AGENTS

描述(改编自申请)：通过制备水溶性络合物， 它们在形状和大小上不同于目前可用的格拉基 核磁共振造影剂--母体复合体近似为球形，约为 12A直径--调查人员希望满足对新产品的需求 靶向特异性造影剂。他们将准备水溶性的衍生物 一个八核Fe(III)-氧代-吡唑簇合物，Fe8(Mu4-O)4(Mu-Pz)12Cl4 (PZ=吡唑拉多阴离子)，因此可以将它们作为潜在对比进行筛选 体内磁共振成像应用的增强剂。父群集具有大型 磁矩，在各种条件下的化学稳定性，以及 几个可用于替代的外围位置，因此，可以操纵 它的大小、形状和溶解度。作为一种可靠的合成这种疏水性 集群建立后，他们现在将通过以下方式制备其水溶性衍生物 通过两种方法在其外围引入亲水性基团：(1) 末端氯配体的取代，和(2)在 空间畅通无阻的4位吡唑环。一旦新的 用标准方法对八核簇合物进行了充分的表征，它们的 弛豫度和生物活性将被测定。

Description (Adapted from Application): By preparing water-soluble complexes, which differ in shape and size from the currently available gadolinium-based MRI contrast agents--the parent complex is approximately spherical with about a 12A diameter--the investigators wish to satisfy the need for new target-specific contrast agents. They will prepare water-soluble derivatives of an octanuclear Fe(III)-oxo-pyrazolato cluster, Fe8(mu4-O)4(mu-pz)12Cl4 (pz=pyrazolato anion), so that they can be screened as potential contrast enhancing agents for in vivo MRI applications. The parent cluster has a large magnetic moment, chemical stability under a wide range of conditions, and several peripheral sites available for substitution, and thus, manipulation of its size, shape, and solubility. As a reliable synthesis of this hydrophobic cluster is established, they will now prepare its water-soluble derivatives by introducing hydrophilic groups at its periphery by two methods: (1) substitution of the terminal chloride ligands, and (2) substitution at the sterically unhindered 4- position of the pyrazole rings. Once the new octanuclear clusters are fully characterized by standard methods, their relaxivity and biological activity will be determined.