Ligand control of low-frequency electron paramagnetic resonance linewidth in Cr(III) complexes.

Understanding how the ligand shell controls low-frequency electron paramagnetic resonance (EPR) spectroscopic properties of metal ions is essential if they are to be used in EPR-based bioimaging schemes. In this work, we probe how specific variations in the ligand structure impact L-band (ca. 1.

Concentration of Fe(3+)-Triapine in BEAS-2B Cells.

An electron paramagnetic resonance (EPR) method was used to determine the concentration of the antitumor agent Triapine in BEAS-2B cells when Triapine was bound to iron (Fe). Knowledge of the concentration of Fe-Triapine in tumor cells may be useful to adjust the administration of the drug or to adjust iron uptake in tumor cells. An EPR spectrum is obtained for Fe(3+)-Triapine, Fe(3+)(Tp), in BEAS-2B cells after addition of Fe(3+)(Tp).

Resolved Hyperfine at L-band for High-Spin CoEDTA, A Model for Co Sites in Proteins.

Low-frequency electron paramagnetic resonance (EPR) spectra were obtained for the Co complex of ethylene diamine tetraacetic acid (CoEDTA). It was found that the cobalt hyperfine at -mid is better resolved at a low frequency, L-band (1.37 GHz), and not resolved at X-band (9.

Treatment of Cells and Tissues with Chromate Maximizes Mitochondrial 2Fe2S EPR Signals.

In a previous study on chromate toxicity, an increase in the 2Fe2S electron paramagnetic resonance (EPR) signal from mitochondria was found upon addition of chromate to human bronchial epithelial cells and bovine airway tissue ex vivo. This study was undertaken to show that a chromate-induced increase in the 2Fe2S EPR signal is a general phenomenon that can be used as a low-temperature EPR method to determine the maximum concentration of 2Fe2S centers in mitochondria. First, the low-temperature EPR method to determine the concentration of 2Fe2S clusters in cells and tissues is fully developed for other cells and tissues.

Better Resolution of High-Spin Cobalt Hyperfine at Low Frequency: Co-Doped Ba(ZnTa)O₃ as a Model Complex.

Low-frequency electron paramagnetic resonance (EPR) is used to extract the EPR parameter -mid and support the approximate X-band value of -mid for Ba(CoZnTa)O₃. Although the cobalt hyperfine structure for the |±1/2〉 state is often unresolved at X-band or S-band, it is resolved in measurements on this compound. This allows for detailed analysis of the molecular orbital for the |±1/2⟩ state, which is often the ground state.