142991-50-2Relevant academic research and scientific papers
Protic media enhanced protodeboronation for a potential H2O2-sensitive ligand system
Mathis, Cheryl L.,Saouma, Caroline T.
, (2020)
The detection of elevated concentrations of reactive oxygen species (ROS) such as H2O2 represents a promising route to identify oxidative misregulation in cells, a hallmark of carcinoma and neurodegeneration. Magnetic resonance imaging (MRI) presents an opportunity to detect ROS over a greater portion of the body compared to strategies such as fluorescence. To sense hydrogen peroxide, potential Fe2+ and Co2+ MRI sensors were synthesized by appending pinacolborane to two amino-pyridine ligand scaffolds. These were designed to expose phenol upon reaction with H2O2, turning on PARACEST (Paramagnetic Chemical Exchange Saturation Transfer) and allowing detection by MRI. Instead of yielding a phenol upon exposure to oxidative conditions, protodeboronation was observed as the major product even under mild conditions. Optimization of oxidation conditions allowed access to the phenolic analogue of the two ligands studied in 11% and 17% conversion under organic conditions. Treatment of the Fe2+ and Co2+ complexes with H2O2 resulted in rapid, partial demetallation with no evidence of the bound or free ligand undergoing an oxidative transformation. These results stress the importance of establishing stability of potential MRI contrast agents in aqueous conditions.
Selective separation of cadmium(II) from zinc(II) by a novel hydrophobic ionic liquid including an N,N,N′,N′-tetrakis(2-methylpyridyl)-1,2-phenylenediamine-4-amido structure: a hard-soft donor combined method
Wu, Hao,Zhang, Xiaoxia,Yin, Xiangbiao,Inaba, Yusuke,Miki, Harigai,Takeshita, Kenji
, p. 10063 - 10070 (2018)
A novel hydrophobic ionic liquid including an N,N,N′,N′-tetrakis(2-methylpyridyl)-1,2-phenylenediamine-4-amido structure ((IL-1,2-tpbd)+NTf2-) was successfully synthesized. (IL-1,2-tpbd)+NTf2- combined one amido (O-hard donor) and four pyridine (N-soft donor) groups. Its Cd2+ and Zn2+ separation behavior in nitric acid solution was investigated as a function of the extraction time, effect of pH etc. by dissolving (IL-1,2-tpbd)+NTf2- in a room temperature ionic liquid, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ((C6mim)+NTf2-). The extraction kinetics were fairly fast and could reach equilibrium within 4 h. When pHeq ≥ 1.8, the extraction percentage of Cd2+ and Zn2+ remained constant and the maximum separation factor was calculated as 12.78 at pHeq = 3.1; when pHeq 2+ and Zn2+ decreased drastically due to the protonation of the pyridine groups. Complete stripping of the extracted Cd2+ and Zn2+ from the ionic liquid phase into an aqueous phase was successfully achieved under highly acidic conditions ([HNO3] = 2 M) without adding any other metal complex forming agents. The extraction mechanism was summarized as a cation exchange due to the independence of nitrate ions in the extraction process. Additionally, the results of the slope analysis and UV-vis titration revealed the formation of a 1?:?2 complex. Furthermore, (IL-1,2-tpbd)+NTf2- showed a higher preference for Cd2+ even under the interference of various co-existing metal ions.
