Fr Francium

New charged cyclometalated iridium(III) complexes [Ir(ppy)₂(L)](PF₆) [ppy = 2-phenylpyridine; L = bis(pyrazol-1-yl)methane (for 1); L = bis(3,5-dimethylpyrazol-1-yl)methane (for 2)] were synthesized and their electrochemical and photophysical properties studied. These complexes with non-π-electron-conjugated ancillary chelates exhibit significantly blueshifted emission relative to those of commonly used derivatives with NN ancillary ligands such as bipyridine or phenanthroline. Both X-ray and theoretical analysis based on time-dependent density functional theory (TD-DFT) reveal that the binding of Ir to the bis(pyrazol-1-yl)methane ancillary ligand is much weaker than that to the phenylpyridine main ligand; the effect is enhanced in the excited state. As a result, the ancillary ligand does not participate in low-energy excitations and triplet emission, and the electronic transitions are concentrated on the main chromophoric ligands. The blueshift feature is attributed to emission originating from the main cyclometalated ligands, in contrast to emitters with the NN chromophoric ancillary ligand. In addition, complex 2 exhibits a one order of magnitude higher non-radiative decay rate than complex 1, which is attributed to the steric hindrance of the methyl groups that leads to a more loosely bound ancillary ligand.

The bis(pyrazol-1-yl)methane ancillary ligand induces a blueshift in the emission of charged cyclometalated iridium(III) complexes. In addition, the nonradiative rate constant increases by one order of magnitude when the ligand is substituted with methyl groups, which induce some steric hindrance and lead to a more loosely bound ancillary ligand.

The preparation of the secondary phosphane (Ph){C₆H₃-2,6-(CH₂NMe₂)₂}PH (1), a potentially base-stabilized ligand, and the sterically protected carbaborane-based phosphane (o-CH₃C₂B₁₀H₁₀)₂PH (2) is reported. Reaction of Sn{N(SiMe₃)}₂ with 1 gives the diphosphastannylene [(Ph){(C₆H₃-2,6-CH₂NMe₂)₂}P]₂Sn (3) in high yield. In contrast, the room-temperature reaction of 2 with Sn{N(SiMe₂)}₂ does not proceed. By applying elevated temperatures, the heteroleptic amidophosphastannylene {(o-CH₃C₂B₁₀H₁₀)₂P}{(SiMe₃)₂N}Sn (4) was formed, instead of the expected diphosphastannylene {(o-CH₃C₂B₁₀H₁₀)₂P}₂Sn. The thermal decomposition of compounds 3 and 4 was also studied. The thermal decomposition of 3 produced the new phosphorus–phosphorus-bonded compound 5, an unprecedented 1,2-diphosphol-type molecule.

Synthesis of diphosphastannylene [(Ph){C₆H₃-2,6-(CH₂NMe₂)₂}P]₂Sn and heteroleptic amidophosphastannylene {(o-CH₃C₂B₁₀H₁₀)₂P}{(SiMe₃)₂N}Sn is reported. The thermal decomposition of [(Ph){C₆H₃-2,6-(CH₂NMe₂)₂}P]₂Sn produced an unprecedented 1,2-diphosphol-type molecule.

The front cover picture shows a schematic representation of the coordination network and the temperature dependence of magnetization of a cyano-bridged V–Nb bimetal assembly, K_0.59V^II_1.59V^III_0.41[Nb^IV(CN)₈]·(SO₄)_0.50·6.9H₂O. This compound exhibits ferrimagnetism with a high Curie temperature (T_C) of 210�K. This temperature is the highest T_C value among those of octacyano-bridged bimetal assemblies. The Short Communication by S. Ohkoshi et al. on p. 2649 ff. demonstrates that the increase in the superexchange pathways of V^II–NC–Nb^IV contributes to the achievement of the high T_C value.

The back cover picture highlights the mechanical and optical properties of a hybrid silica-PHEMA coating on glass reinforced by using goethite nanorods in relation with the local structure at the interface. We demonstrate the possibility to finely tune the final mechanical properties by adjusting the coating silica content. In this hybrid nanocomposite, goethite particles exhibit interesting stress relaxation functions, which prevent crack formation in the films whilst reaching high silica content in the hybrid matrix. Details are discussed in the article by N. Chemin, C. Chanéac et al. on p. 2675 ff.

The use of microwave heating for the synthesis of (N-heterocyclic carbene)-bearing complexes of Cu, Ag and Au allows for a drastic reduction of the reaction times required by conventional heating, while affording comparable or better yields of the desired complexes.

The use of microwave heating for the direct synthesis of (NHC)MCl complexes (NHC = N-heterocyclic carbene; M = Cu, Ag, Au) in very short reaction times is presented. Comparable or better yields than those reported by using conventional heating can be obtained with this protocol.

To identify the chemical species involved in a unique, vanadium-based chemical oscillator reaction, products derived from indole in the oscillation solution were isolated and characterized. NMR and mass spectra showed that 3,3-dichloro-2-oxoindole and isatin were formed during the oscillation process. The formation of these two compounds suggests that peroxo species such as CHCl₂OO^· and CHCl₂OOH play a key role in the construction of the oscillation system. A skeletal model for the system is proposed based on these findings.

Products derived from indole in a vanadium-based oscillation solution were identified to be 3,3-dichloro-2-oxoindole and isatin. Peroxo species such as CHCl₂OO^· and CHCl₂OOH were found to play a key role in the construction of the chemical oscillation system. A skeletal model for the oscillation reaction is proposed.