Ultrawide Band Multifrequency High-Field EMR Technique: A Methodology for Increasing Spectroscopic Information

Effects of Terminal Dimethylation and Metal Coordination of Proline-2-formylpyridine Thiosemicarbazone Hybrids on Lipophilicity, Antiproliferative Activity, and hR2 RNR Inhibition

“…3 to 10 K were recorded on a home-built spectrometer at the EMR facility of the NHMFL. 69 The instrument is a transmission-type device in which microwaves are propagated in cylindrical lightpipes. The microwaves were generated by a phase-locked Virginia Diodes source generating frequency of 13 ± 1 GHz which was multiplied by a cascade of frequency doublers and/or triplers.…”

EPR Spectroscopy

“…Within the same decade the application field in structural biology was extended tremendously by the introduction of site-directed spin labeling [17], which made diamagnetic proteins accessible to EPR spectroscopy, among them many that were difficult to study by x-ray crystallography or NMR spectroscopy. The third major development of the 1990s was the systematic combination of EPR measurements at multiple frequencies (multi-frequency EPR) to study more complex problems, and, in particular, the extension to higher fields and frequencies, made possible by new microwave technology and by the superconducting magnet technology developed for NMR spectroscopy [18,19].…”

High-Frequency EPR Instrumentation

“…The MVNA developed by the company ABmm has an unrivaled dynamic range and has been used in several laboratories involved in multi-high-frequency EPR [45,49,57,73]. The sources up to 300 GHz are based on YIG oscillators in combination with harmonic generators.…”

“…In the simplest (''optical'') configuration, the sample holder is positioned in ''transmission''. In the original ''Grenoble configuration'' [45,72], a double copper pipe is inserted into the sample cryostat. Mirrors inserted into the pipes allow for 90°bends connecting the source and detector pipes as well as the transmission sample holder.…”

“…Brunel et al [43][44][45] realized a multifrequency HF-EPR spectrometer, which is optimized for the study of high-spin systems and radical species. Several laboratories followed similar schemes and developed multi-high-frequency instruments dedicated to a particular class of samples [46][47][48][49].…”