title: Distance measurements in Au nanoparticles functionalized with nitroxide radicals and Gd(3+)-DTPA chelate complexes.
abstract: Nanosized gold particles were functionalised with two types of paramagnetic surface tags, one having a nitroxide radical and the other one carrying a DTPA complex loaded with Gd(3+). Selective measurements of nitroxide-nitroxide, Gd(3+)-nitroxide and Gd(3+)-Gd(3+) distances were performed on this system and information on the distance distribution in the three types of spin pairs was obtained. A numerical analysis of the dipolar frequency distributions is presented for Gd(3+) centres with moderate magnitudes of zero-field splitting, in the range of detection frequencies and resonance fields where the high-field approximation is only roughly valid. The dipolar frequency analysis confirms the applicability of DEER for distance measurements in such complexes and gives an estimate for the magnitudes of possible systematic errors due to the non-ideality of the measurement of the dipole-dipole interaction.
authors: Laboratory of Physical Chemistry, ETH Zurich, Wolfgang Pauli Str.10, 8093, Zurich, Switzerland. maxim.yulikov@phys.chem.ethz.ch
authors: Maxim
authors: M
authors: Yulikov
authors: Petra
authors: P
authors: Lueders
authors: Muhammad Farooq
authors: MF
authors: Warsi
authors: Victor
authors: V
authors: Chechik
authors: Gunnar
authors: G
authors: Jeschke
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005682:Gadolinium / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry*; D004369:Pentetic Acid / Q000737:chemistry*; D013113:Spin Labels
chemical_list: D056831:Coordination Complexes; D009589:Nitrogen Oxides; D013113:Spin Labels; D006046:Gold; D004369:Pentetic Acid; D005682:Gadolinium; C039900:nitroxyl