European Journal of Inorganic Chemistry

This Microreview gives an up-to-date account of the advances made by the author's group and by other groups, in recent years, on spin-crossover compounds of iron(II), iron(III) and cobalt(II) of the dinuclear cluster and 1-D chain types. As well as describing their syntheses, design, structures, magnetism and photomagnetism, a systematic delineation of the kinds and mechanisms of observed spin transitions is presented.

The reaction of Co^II and 2,2′-dipyridyldisulfide (PySSPy) in the presence of azide produced a monomeric complex [Co^III(PyS)(PyS-N-SPy)(N₃)] (1), which was characterized by means of UV/Vis, X-ray crystallography, XPS, and cyclic voltammetry. The unusual, N-inserted ligand PyS-N-SPy can be stabilized through coordination to the electropositive Co^III ion.

NaBH₄·2H₂O and NaBH₄ were studiedby single-crystal X-ray diffraction andvibrational spectroscopy. Nearly ideal tetrahedral BH₄^– anions are bridged with Na⁺ ions through the edges. NaBH₄·2H₂O does not contain classical hydrogen bonds, but reveals strong O–H^δ+···^δ–H–B bonds. At 313–315 K, the structure decomposes into NaBH₄ and H₂O, which react to form hydrogen gas.

The reaction of [α₂-P₂W₁₇O₆₁]^10– with [Re^IVCl₆]^2– in water afforded K₁₄[O{Re^V(OH)(α₂-P₂W₁₇O₆₁)}₂]·21H₂O (K-1), whose single-crystal X-ray structure analysis revealed overall C₂h symmetry. K-1 was grafted onto a TiO₂ surface by electrostatic binding to give TiO₂ with a cationic quaternaryammonium moiety (1-grafted TiO₂), which effected hydrogen evolution from water vapor under visible light irradiation.

We present the syntheses and the molecular structures of novel palladacycles and theircatalytic activities in Suzuki and Heck reactions.

Lanthanide complexes of N-confused porphyrins with different rare-earth metals and phenyl ring substituents are synthesized in which the tripodal cobaltate anion acts as an effective encapsulating agent for Ln³⁺ and an η²-agostic interaction exists between the metal center and the innerC–H bond of the porphyrinate ligand.

Sol–gel synthesis of cerium titanates with tunable Ce³⁺/Ce⁴⁺ content, crystalline structure and optical properties are reported. XRD, Raman spectroscopy and magnetic measurements corroborate the crystallization of CeO₂–TiO₂ mixed oxides or Ce₂Ti₂O₇ pyrochlore phase. The Ce^III oxidation process affects the colouration, leading to ecological pigments with promising applications in catalysis.

From a facile catalyst-free method, pure single-crystalline nanotetrapod-assembled ZnO was grown on a gram-scale for the first time, with high repeatability and conversion efficiency. All four arms of thenanotetrapods are cone shaped and grow in the [001] direction. The photoluminescence properties were studied and a mechanism was suggested for the growth of the nanotetrapod-assembled ZnO.

Alkylzinc carbamates suitable as precursors to ZnO nanosized particles under mild conditions are formed by CO₂ insertion into the Zn–N bonds of alkylzinc amides.

The BN bond lengths and the planar borazine ring are distorted in the solid state by substituents in three different ways: a) by retaining the planarity of the borazine ring but with substituents bent up and down thering, b) by substituents that induce different BN bond lengths and bond ring bond angles and c) by distortion of the borazine ring into a chair shaped or twisted ring.

A series of β-diketonate, β-ketoiminate, and β-diiminate complexes of difluoroboron have been prepared to evaluate the effects of chelate ring substitution on the structural and electronic properties. The electron-accepting nature of the ligands likely facilitates unusual coordination chemistry.

[Ru(η⁵-C₅Me₄R)(MeCN)₃][PF₆] (R =tBuCH₂, iPr, tBu and CF₃) complexes were synthesized and evaluated as catalysts for nucleophilic allylic substitution reactions.

In the epoxidation of cyclooctene and cis-stilbene by tetra-n-butylammonium periodate and (tetraarylporphyrinato)manganese(III) in the presence of imidazole in CH₂Cl₂, the molecular size and acidity of the alcohols played important roles in determining the epoxidation yields and the cis- to trans-stilbene oxide ratio and in the generation and stabilization of the [Mn(por)(O)(im)]⁺ species.