title: Complexation of copper(II)-Chelidamate: A multifrequency-pulsed electron paramagnetic resonance and electron nuclear double resonance analysis.
abstract: Multifrequency electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) techniques were used to obtain structural information about the copper(II)-chelidamate complex. Well-resolved nitrogen ENDOR spectra could be recorded from solid solution samples by using selective excitation of spin packets. Evaluation of nuclear quadrupole and dipolar hyperfine interaction of the directly ligated nitrogen allowed for an identification of the bond direction to the copper ion within the eigen frame of the copper g-matrix. Invoking two-dimensional EPR techniques, additional hyperfine interaction with a "distant" nitrogen spin, identified as resulting from the solvent dimethylformamide (DMF), was observed. The experimental data are only consistent with formation of a stable pseudoplanar copper complex with single solvent ligation via its oxygen atom.
authors.affiliation: Eduard-Zintl-Institute and Clemens-Schöpf-Institute, Darmstadt University of Technology, D-64287 Darmstadt, Germany.
authors.forename: Elvir
authors.initials: E
authors.lastname: Ramić
authors.forename: Rüdiger-Albert
authors.initials: RA
authors.lastname: Eichel
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Dinse
authors.forename: Alexander
authors.initials: A
authors.lastname: Titz
authors.forename: Boris
authors.initials: B
authors.lastname: Schmidt
mesh_terms: D001703:Biophysics / Q000379:methods; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper / Q000737:chemistry*; D004126:Dimethylformamide / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D004583:Electrons; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry; D011728:Pyridones / Q000737:chemistry*; D013053:Spectrophotometry
chemical_list: D008024:Ligands; D011728:Pyridones; C042436:chelidamic acid; D003300:Copper; D004126:Dimethylformamide; D010100:Oxygen