Do not tumble dry: Gadolinium-DOTA encapsulated into polysaccharide nanoparticles (GdDOTA NPs) exhibited high relaxivity (r(1) =101.7 s(-1) mM(-1) per Gd(3+) ion at 37 °C and 20 MHz). This high relaxation rate is due to efficient Gd loading, reduced tumbling of the Gd complex, and the hydrogel nature of the nanoparticles. The efficacy of the nanoparticles as a T(1)/T(2) dual-mode contrast agent was studied in C6 cells.

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A cyclic dodecanuclear nickel complex is the first single molecule magnet based on nickel(II) centres; the material is also the highest spin molecule to show resonant quantum tunnelling of magnetisation.

A series of hydrogel nanoparticles incorporating MRI contrast agents (GdDOTP and MS325) as potential cross-linkers were elaborated by an easy and robust ionotropic gelation process.

We present the results of muon spin relaxation (µ + SR) studies on low dimensional molecular magnet systems. µ + SR measurements have been carried out on the Cu-based chain compounds CuX 2 (pyz) (where X = Br, Cl, NCS and pyz = pyrazine) as a function of temperature and applied longitudinal magnetic field. Oscillations in the time dependence of the muon polarization, characteristic of magnetic order at two distinct muon sites, are detected in both CuBr 2 (pyz) (below T N = 3.6(1) K) and CuCl 2 (pyz) (below T N = 3.2(2) K). No evidence of magnetic order is observed in Cu(NCS) 2 (pyz) down to 0.35 K. The results are discussed in terms of the estimated Cu-X-Cu and Cu-(pyz)-Cu exchange constants. The theory of µ + SR in high spin molecule (HSM) systems, which are effectively zero-dimensional magnets, is discussed and results are presented on [Ni 12 (chp) 23). Measurements made in applied longitudinal magnetic fields on HSM materials at dilution refrigerator temperatures strongly suggest that dynamic local magnetic field fluctuations are responsible for the relaxation of the muon spin ensemble. Trends in temperature and field dependent behaviour in these systems, as probed by the muon, are discussed.

The synthesis, structural characterisation and preliminary magnetic studies of a Co12 wheel are reported; the magnetic investigations reveal that the electronic ground state has a spin S = 6, which corresponds to ferromagnetic interactions between the twelve Co(II) ions.

A variety of perylenetetracarboxy-3,4:9,10-diimide derivatives have been synthesized. Particular attention was paid to substituents in positions 1, 6, 7 or 12. The energy differences between the frontier orbitals have been determined using optical spectroscopy (UV and fluorescence). The energy of the lowest unoccupied orbitals (LUMOs) were obtained by cyclic voltammetry. From both studies, the energies of the highest occupied orbitals (HOMOs) were also been calculated. A Hammett-type relationship was observed for the reduction potentials (E red1 1/2 ) when correlated with the s À ortho parameter. The energies of the frontier orbitals define the domains of application of these compounds. They significantly depend on the substitution in positions 1, 6, 7, or 12.

Keywords:Copper / Cyclen and cyclam ligands / X-ray diffraction / UV/Vis and EPR spectroscopy / Electrochemistry / Configurational isomerisation