title: Solid-state NMR correlation experiments and distance measurements in paramagnetic metalorganics exemplified by Cu-cyclam.
abstract: We show how to record and analyze solid-state NMR spectra of organic paramagnetic complexes with moderate hyperfine interactions using the Cu-cyclam complex as an example. Assignment of the (13)C signals was performed with the help of density functional theory (DFT) calculations. An initial assignment of the (1)H signals was done by means of (1)H-(13)C correlation spectra. The possibility of recording a dipolar HSQC spectrum with the advantage of direct (1)H acquisition is discussed. Owing to the paramagnetic shifting the resolution of such paramagnetic (1)H spectra is generally better than for diamagnetic solid samples, and we exploit this advantage by recording (1)H-(1)H correlation spectra with a simple and short pulse sequence. This experiment, along with a Karplus relation, allowed for the completion of the (1)H signal assignment. On the basis of these data, we measured the distances of the carbon atoms to the copper center in Cu-cyclam by means of (13)CR2 relaxation experiments combined with the electronic relaxation determined by EPR.
authors.affiliation: Institut des Molécules et Matériaux du Mans (IMMM), UMR CNRS 6283, LUNAM, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans, France.
authors.forename: Shashi K
authors.initials: SK
authors.lastname: Kumara Swamy
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Karczmarska
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Makowska-Janusik
authors.forename: Abdelhadi
authors.initials: A
authors.lastname: Kassiba
authors.forename: Jens
authors.initials: J
authors.lastname: Dittmer
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics
chemical_list: D002247:Carbon Isotopes; D056831:Coordination Complexes; D006571:Heterocyclic Compounds; C024560:cyclam; D003300:Copper; D006859:Hydrogen