Coordination of Cu(II) to lipophilic bis-hydroxamate binders as studied by one- and two-dimensional electron spin echo spectroscopy

A study was conducted on the binding of Cu(II) to the lipophilic bis-hydroxamate binder RL252 and its parent, RL239. Orientation-selective three-pulse electron spin echo envelope modulation spectroscopy and two-dimensional hyperfine sublevel correlation experiments were performed to investigate the binding geometry. Both binders were found to share similar electron paramagnetic resonance spectra. The spectrum of Cu-RL239 indicated the existence of an additional minor species.