title: Theoretical calculation of the magnetic resonance parameters of trigonal-prismatic tris(o-aminobenzenethiol)technetium and -rhenium complexes.
abstract: Spin Hamiltonian parameters for the neutral trigonal-prismatic Tc(abt)(3) and Re(abt)(3) chelates (abt = o-aminobenzenethiol) are calculated using relativistic density functional theory at the all-electron level. The small magnitude of the calculated g shifts and metal hyperfine interactions is in excellent agreement with previous experimental predictions based upon a ligand-centered ground-state magnetic orbital. The theoretical (14)N ligand hyperfine and quadrupole couplings also reproduce the nuclear frequencies measured by electron spin-echo envelope modulation spectroscopy. The nuclear quadrupole interaction of (187)Re is predicted to be 2 orders of magnitude larger than that of (99)Tc, in agreement with empirical simulation of the continuous-wave electron paramagnetic resonance spectrum. The spectrum of Tc(abt)(3) at high solute concentrations contains a central resonance not predicted for the isolated complex by theoretical calculations. The absence of this resonance at low solute concentrations provides evidence of intermolecular interactions in these systems.
authors.affiliation: Max Planck Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany. drew@mpi-muelheim.mpg.de
authors.forename: Simon C
authors.initials: SC
authors.lastname: Drew
authors.forename: John
authors.initials: J
authors.lastname: Baldas
authors.forename: John F
authors.initials: JF
authors.lastname: Boas
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D011789:Quantum Theory; D012211:Rhenium / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013667:Technetium / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D010636:Phenols; D013438:Sulfhydryl Compounds; D012211:Rhenium; D013667:Technetium; C042983:thiophenol