cm3 mol(-1) for [Eu(dotam)(H2O)]3+ and + 6.9 cm3 mol(-1) for [Eu(dtma)(H2O)]3+). The overall water exchange only depends on the M/m isomeric ratio. The m isomer, which exchanges more quickly, is favoured by a-substitution of the ring nitrogen. Therefore the synthesis of DOTA-like ligands, which predominantly form complexes in the m form, should be a sufficient condition to ensure faster water exchange
1 H NMR线形分析和在可变温度和压力下的磁化传递实验已用于阐明三种[Eu(dota-tetraamide)(H2O)] 3+配合物的M和m异构体的溶液动力学。结合水信号的直接1H NMR观察值可以分别测量每个异构体上的水交换速率。它们绝对独立于M和m异构体的配体(对于[Eu(dotam)(H2O)] 3+,M:k298(ex)= 9.4 +/- 0.2 x 10(3)s(-1) [Eu(dtma)(H2O)] 3+的+/- 0.2 x 10(3)s(-1)和[Eu(dotmam)-([ H2O)] 3+; m:[Eu(dotam)(H2O)3+,k298(ex)= 474 +/- 130 x 10(3)s(-1),357 +/- 92 x 10(3) [Eu(dtma)(H2O)3+)的s(-1),并通过解离机理进行(M异构体:[Eu(dotam)(H2O)] 3+的deltaV ++