Protic media enhanced protodeboronation for a potential H2O2-sensitive ligand system
摘要:
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. (C) 2020 Elsevier Ltd. All rights reserved.
Aliphatic C–H Bond Halogenation by Iron(II)-α-Keto Acid Complexes and O<sub>2</sub>: Functional Mimicking of Nonheme Iron Halogenases
作者:Rahul Dev Jana、Debobrata Sheet、Sayanti Chatterjee、Tapan Kanti Paine
DOI:10.1021/acs.inorgchem.8b00421
日期:2018.8.6
nonheme halogenases catalyze the halogenation of aliphatic C–H bonds in the biosynthesis pathway of many natural products. An iron(IV)-oxo-halo species has been established as the active oxidant in the halogenation reactions. With an objective to emulate the function of the nonheme halogenases, two iron(II)-α-keto acid complexes, [(phdpa)Fe(BF)Cl] (1) and [(1,4-tpbd)Fe2(BF)2Cl2] (2) (where phdpa = N
A novel fluorescent chemosensor 1 for imaging labile Cu2+ in living biological samples was designed and synthesized; it exhibits very strong fluorescence responses to Cu2+, and its LSM images strongly support the existence of Cu2+ in HEGP-2 cell
Quantifying factors that influence metal ion release in photocaged complexes using ZinCast derivatives
作者:Celina Gwizdala、Charlene V. Singh、Tracey R. Friss、John C. MacDonald、Shawn C. Burdette
DOI:10.1039/c2dt30135k
日期:——
tridentate ZinCast-1 utilizes a bis-pyridin-2-ylmethyl-aniline ligand that forms a 5,5-chelate ringuponmetalbinding. The related photocages ZinCast-2 with a N-[2-(pyridine-2-yl)ethyl]-N-(pyridine-2-ylmethyl)aniline (5,6-chelate ring) and ZinCast-3 with a N,N-bis[2-(pyridine-2-yl)ethyl]aniline (6,6-chelate ring) were synthesized for comparative studies. The complexes formed by the ions Cu2+, Zn2+ and
An Unsymmetrical Squaraine-Dye-Based Chemical Platform for Multiple Analyte Recognition
作者:Divya S. Philips、Samrat Ghosh、Karivachery V. Sudheesh、Cherumuttathu H. Suresh、Ayyappanpillai Ajayaghosh
DOI:10.1002/chem.201703645
日期:2017.12.19
which acts as the metal ionreceptor, whereas the other part of the molecule carries a dibutylaniline moiety, which is an electron donor. The molecular system is unique because it can respond specifically to different types of analytes, namely, atmospheric carbon dioxide, cyclic phosphates, and picric acid. Moreover, the interaction of these analytes can be monitored colorimetrically and fluorimetrically