Magneto-structural Correlations in Ni-Halide···Halide-Ni Chains.

We present the magnetic properties of a new family of = 1 molecule-based magnets, NiF(3,5-lut)·2HO and NiX(3,5-lut), where X = HF, Cl, Br, or I (lut = lutidine CHN). Upon creation of isolated Ni-X···X-Ni and Ni-F-H-F···F-H-F-Ni chains separated by bulky and nonbridging lutidine ligands, the effect that halogen substitution has on the magnetic properties of transition-metal-ion complexes can be investigated directly and in isolation from competing processes such as Jahn-Teller distortions. We find that substitution of the larger halide ions turns on increasingly strong antiferromagnetic interactions between adjacent Ni ions via a novel through-space two-halide exchange.

Self-Induced Crystallization in Charged Gold Nanoparticle-Semiflexible Biopolyelectrolyte Complexes.

Mixing negatively charged polyelectrolyte (PEL) with positively charged gold nanoparticles (Au NPs) in aqueous solution results in electrostatics complexes of different shapes and compactness. Here, when complexing with a semirigid PEL hyaluronic acid (HA), we obtain crystals made of nanoparticles in a new region of the phase diagram, as evidenced by small-angle X-ray scattering (SAXS). The Au NPs were initially well dispersed in solution; their size distribution is well controlled but does not need to be extremely narrow.