Antiferromagnetic Interactions through the Thirteen Å Metal-Metal Distances in Heterometallic One-dimensional Chains.

A heterometallic and paramagnetic one-dimensional aligned chain in -Rh(+2)-Rh(+2)-Pt(+2)-Ni(+2)-Pt(+2)- with direct metal-metal bonds was obtained via HOMO-LUMO interactions at the σ* (dz2) orbital between [Rh2(O2CCH3)4] and [Pt2Ni(piam)4(NH3)4] (piam = pivalamidate). The one-dimensional chains had straight backbones attributed to face-to-face stacking of each complex, and the Ni atoms were separated by approximately 13 Å from four different metals. Each Ni atom had two unpaired electrons in the d-orbitals, which strongly exchanged with J = -37.9 cm-1 through the diamagnetic -Pt-Rh-Rh-Pt- bonds.

Aromatic Fluorine-Induced One-Pot Synthesis of Ring-Perfluorinated Trimethine Cyanine Dye and Its Remarkable Fluorescence Properties.

We have developed a novel aromatic fluorine-induced one-pot synthesis of ring-perfluorinated trimethine cyanine dye without the use of a pyridine by reacting hexafluorobenzoindolenine with 5 equiv of methyl trifluoromethanesulfonate in mixed solvents of dimethylformamide and toluene. The thus-obtained ring-perfluorinated trimethine cyanine dye shows much better fluorescence properties, including intensity, quantum yield, and lifetime, than the nonfluorinated dye, not only in CH2Cl2 solution and the poly(methyl methacrylate) film but also in the powder state. Furthermore, ring-perfluorinated trimethine cyanine dye 2a shows better photostability toward white light-emitting diode irradiation than nonfluorinated dye trimethine cyanine dye 2b.

Homogeneous nucleation of corundum nanocrystallites by rapid heating of aluminum formate hydroxide-based precursor powder.

The high density nucleation of α-Al2O3 nanocrystallites was observed by rapid heating of the aluminum formate hydroxide-based precursor powder at 1200 °C for 50 s. The nucleation of α-Al2O3 nanocrystallites with less 10 nm in size from high purity aluminum oxide matrix has not been observed to our knowledge. Based on the results of XRD and TEM, α-Al2O3 nanocrystallites nucleated from the amorphous phase which formed after thermal decomposition of the precursor powder. Subsequently, α-Al2O3 with hollow rod-like morphology formed through coalescence and growth of nanocrystallites after heating at 1200 °C for 1 min. The results obtained in this paper indicates a possible beneficial effect of the rapid heating and cooling of the aluminum formate hydroxide-based precursor powder on the precipitation of α-Al2O3 nanocrystallites.