A ditopic DTPA monoamide derivative containing an 8-hydroxyquinoline moiety was synthesized and the corresponding gadolinium(III) complex ([Gd(H5)(H2O)]−) was prepared. After adding aluminum(III), the 8-hydroxyquinoline part self-assembled into a heteropolymetallic triscomplex [(Gd5)3Al(H2O)3]3−. The magnetic and optical properties of this metallostar compound were investigated in order to classify it as a potential in vitro bimodal contrast agent. The proton nuclear magnetic relaxation dispersion measurements indicated that the relaxivity r1 of [Gd(H5)(H2O)]− and [(Gd5)3Al(H2O)3]3− at 20 MHz and 310 K equaled 6.17 s−1 mM−1 and 10.9 s−1 mM−1 per Gd(III) ion respectively. This corresponds to a relaxivity value of 32.7 s−1 mM−1 for the supramolecular complex containing three Gd(III) ions. The high relaxivity value is prominently caused by an increase of the rotational tumbling time τR by a factor of 2.7 and 5.5 respectively, in comparison with the commercially used MRI contrast agent Gd(III)–DTPA (Magnevist®). Furthermore, upon UV irradiation, [(Gd5)3Al(H2O)3]3− exposes green broad-band emission with a maximum at 543 nm. Regarding the high relaxivity and the photophysical properties of the [(Gd5)3Al(H2O)3]3− metallostar compound, it can be considered as a lead compound for in vitro bimodal applications.
合成了一种含有
8-羟基喹啉分子的二硝基
DTPA 单
酰胺衍
生物,并制备了相应的
钆(III)配合物([Gd(H5)(
H2O)]-)。加入
铝(III)后,
8-羟基喹啉部分自组装成了杂多
金属三混合物[(Gd5)3Al( )3]3-。为了将其归类为一种潜在的体外双模造影剂,我们对这种
金属星化合物的磁学和光学特性进行了研究。质子核磁弛豫色散测量结果表明,在 20
MHz 和 310 K 下,[Gd(H5)( )]- 和 [Gd5)3Al( )3]3- 的弛豫率 r1 分别等于每个 Gd(III)离子 6.17 s-1 mM-1 和 10.9 s-1 mM-1。这相当于含有三个
钆(III)离子的超分子复合物的弛豫值为 32.7 s-1 mM-1。与市场上使用的磁共振成像造影剂 Gd(III)-
DTPA (Magnevist®)相比,旋转翻滚时间 τR 分别增加了 2.7 倍和 5.5 倍,从而显著提高了弛豫值。此外,在紫外线照射下,[(Gd5)3Al( )3]3- 会发出绿色宽带辐射,最大波长为 543 纳米。鉴于[(Gd5)3Al( )3]3-
金属星化合物的高弛豫性和光物理性质,可将其视为体外双模应用的先导化合物。