Evaluation of Water Exchange Kinetics on [Ln(AAZTAPh–NO<sub>2</sub>)(H<sub>2</sub>O)<sub><i>q</i></sub>]<sup><i>x</i></sup> Complexes Using Proton Nuclear Magnetic Resonance
作者:Shima Karimi、Lorenzo Tei、Mauro Botta、Lothar Helm
DOI:10.1021/acs.inorgchem.6b00976
日期:2016.6.20
on [Ln(AAZTAPh–NO2)(H2O)q]− (Ln = Gd3+, Dy3+, or Tm3+) were determined by 1H nuclear magnetic resonance (NMR) measurements. The number of inner-sphere water molecules was found to change from two to one when going from Dy3+ to Tm3+. The calculated water exchange rate constants obtained by variable-temperature proton transverse relaxation rates are 3.9 × 106, 0.46 × 106, and 0.014 × 106 s–1 at 298 K
[Ln(AAZTAPh–NO 2)(H 2 O)q ] -(Ln = Gd 3+,Dy 3+或Tm 3+)上的水交换动力学通过1 H核磁共振(NMR)测量确定。当从Dy 3+变为Tm 3+时,发现内层水分子的数量从2变为1 。通过变温质子横向弛豫率得到所计算出的水交换速率常数是3.9×10 6,0.46×10 6,和0.014×10 6小号-1在298K为钆3+,镝3+,和Tm 3+。使用可变压力测量来评估水交换机理。结果表明,Gd 3+和Dy 3+配合物的ΔV oci值分别为-1.4和1.9 cm 3 mol –1缔合和解离交换机理。缔合激活模式(I一个或A机构)是为得到的Tm 3+络合物(Δ V ⧧ = -5.6厘米3摩尔-1)。此外,[Dy(AAZTAPh–NO 2)(H 2 O)2 ] - 具有很高的横向弛豫度值的薄膜被认为是用于高场成像应用的负性造影剂的潜在候选者。