170655-44-4Relevant articles and documents
Electronic Effects of Ligand Substitution in a Family of CoII2 PARACEST pH Probes
Thorarinsdottir, Agnes E.,Tatro, Scott M.,Harris, T. David
, p. 11252 - 11263 (2018)
We report three new Co2-based paramagnetic chemical exchange saturation transfer (PARACEST) probes with the ability to ratiometrically quantitate pH. A CoII2 complex, [LCo2(etidronate)]-, featuring tetra(carboxamide) and OH-substituted etidronate ligands with opposing pH-dependent CEST peak intensities, was previously shown to exhibit a linear correlation between log(CESTOH/CESTNH) and pH in the pH range 6.5-7.6 that provided a sensitivity of 0.99(7) pH unit-1 at 37 °C. Here, we demonstrate through a series of CF3-functionalized CoII2 complexes [(XL′)Co2(etidronate)]- (X = NO2, F, Me), that modest changes in the electronic structure of CoII centers through remote ligand substitution can significantly affect the NMR and CEST properties of Co2-based PARACEST probes. Variable-pH NMR and CEST analyses reveal that the chemical shifts of the ligand protons are highly affected by the nature of the X substituent. The ratios of OH and NH CEST peak intensities at 115 and 88, 93 and 79, and 88 and 76 ppm for X = NO2, F, and Me, respectively, afford pH calibration curves with remarkably high sensitivities of 1.49(9), 1.48(7), and 2.04(5) pH unit-1 across the series. The 1.5-2-fold enhancement in pH sensitivity for the CF3-functionalized Co2 probes stems from the complete separation of the OH and NH CEST peaks. Furthermore, incorporation of electron-withdrawing CF3 groups shifts the detection window to a more acidic range of pH 6.2-7.4. Finally, the CoII2 complexes are found to be extremely robust toward substitution and oxidation in aqueous solutions. Taken together, these results highlight the unique ability of transition metal-based PARACEST probes to provide a highly sensitive concentration-independent measure of pH and demonstrate that modest ligand modifications can be a powerful tool for optimizing the pH sensing performance of these probes.
Discovery and Optimization of Glucose Uptake Inhibitors
Liu, Kevin G.,Kim, Ji-In,Olszewski, Kellen,Barsotti, Anthony M.,Morris, Koi,Lamarque, Christophe,Yu, Xuemei,Gaffney, Jack,Feng, Xiao-Jiang,Patel, Jeegar P.,Poyurovsky, Masha V.
supporting information, p. 5201 - 5211 (2020/07/10)
Aerobic glycolysis, originally identified by Warburg as a hallmark of cancer, has recently been implicated in immune cell activation and growth. Glucose, the starting material for glycolysis, is transported through the cellular membrane by a family of glucose transporters (GLUTs). Therefore, targeting glucose transporters to regulate aerobic glycolysis is an attractive approach to identify potential therapeutic agents for cancers and autoimmune diseases. Herein, we describe the discovery and optimization of a class of potent, orally bioavailable inhibitors of glucose transporters, targeting both GLUT1 and GLUT3.
A CoII complex for19F MRI-based detection of reactive oxygen species
Yu, Meng,Xie, Da,Phan, Khanh P.,Enriquez, José S.,Luci, Jeffrey J.,Que, Emily L.
supporting information, p. 13885 - 13888 (2016/12/06)
A fluorinated, air-stable cobalt(ii) complex serves as a turn-on19F magnetic resonance imaging (MRI) tracer for reactive oxygen species including H2O2. Upon oxidation with H2O2, the complex converts from paramagnetic high spin CoII to diamagnetic low spin CoIII resulting in a chemical shift change and enhancement in19F NMR signal. Further, the oxidation can be reversed in the presence of reductant Na2S2O4. The turn-on response is demonstrated by19F MRI, characterized by a ～2-3 fold enhancement in signal.
