Single crystals of an iron(II) spin crossover (SCO) complex containing N2O Schiff base ligand, [FeII(qsal-COOH)2], were successfully prepared. The crystal structures from a single-crystal X-ray diffraction study obtained at 100 and 170 K yielded information regarding both the low-spin high-spin states, without any breakage being observed after phase transition. Structural analysis was performed...

The iron abundance relative to α-elements in the circumnuclear region of quasars is regarded as a clock of the star formation history and, more specifically, of the enrichment by type Ia supernovae (SNIa). We investigate the iron abundance in a sample of 22 quasars in the redshift range 3.0<z<6.4 by measuring their rest frame UV FeII bump, which is shifted into the near-IR, and by comparing it ...

Archival observations of 18 starburst galaxies that span a wide range in metal-licity reveal for the first time a correlation between the ratio of emission line fluxes of [FeII] at 26 µm and [NeII] at 12.8 µm and the 7.7 µm PAH strength, with the [FeII]/[NeII] flux ratio decreasing with increasing PAH strength. We also find a strong correlation between the [FeII]/[NeII] flux ratio and the host ...

The enantiomerically pure chiral tris-chelating ligand (+)-(7S,10R)-L(L) comprising three 4,5-pinenobipyridine subunits connected through a mesityl spacer has been synthesized. Complexes of L with RuII and FeII have been prepared and characterised. NMR spectroscopy indicates that only one diastereoisomer is formed, and the CD spectra show that the complexes have the [capital Lambda] configurati...

We investigated the FeII optical emission in a sample of about 220 low-redshift quasars and luminous Seyfert 1 galaxies. We found that a scaled and broadened FeII template based on the I Zw 1 spectrum satisfactorily reproduce the FeII emission of almost all AGN of our sample. We also confirm that FWHM of Hβ and FeIIλ4570 are tightly correlated. However, the correlation takes two slightly differ...

A novel series of mixed-valent, heteroleptic transition metal diketonates that can be utilized as prospective single-source precursors for the low-temperature preparation of oxide materials are reported. The first mixed-valent iron β-diketonates with different FeIII/FeII ratios have been synthesized by applying the mixed-ligand approach. Based on nearly quantitative reaction yields and analysis...

Complexation of the tetrapodal pentadentate NN4 ligand 2,6-C5H3N[CMe(CH2NH2)2]2 (I) with iron(II) perchlorate hydrate in methanol, in the presence of N-methylimidazole, produces a diferrous complex with a single, unsupported mu-OH ligand between two {(I)FeII} coordination modules.

In weakly coordinating solvents FeII meso-(N-methylimidazol-2-yl)porphine Fe exists as a stable dimer (Kd=50+/-30 nM) that binds ligands without undergoing dissociation and is presently the simplest complex in which the mono-imidazole ligation of a ferroheme is enforced without excess imidazole in solution.

The reactivity between a thiolate-ligated five-coordinate complex [FeII(SMe2N4(tren))]+ (1) and dioxygen is examined in order to determine if O2 activation, resembling that of the metalloenzyme cytochrome P450, can be promoted even when O2 binds cis, as opposed to trans, to a thiolate. Previous work in our group showed that [FeII(SMe2N4(tren))]+ (1) reacts readily with superoxide (O2-) in the p...

Simultaneous determination of FeII and FeIII mixtures by spectrophotometric methods is a difficult problem in analytical chemistry because of spectral interferences. By multivariate calibration methods, such as partial least squares (PLS), it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. The method is based on developing the re...