The analytical applications of the evolved gas analyses (EGAs) performed by mass spectrometry for the period extending from 2005 to 2010 are collected in this review. By EGA, the nature of volatile products released by a substance subjected to a controlled temperature program are determined on-line, with the possibility to prove a supposed reaction either under isothermal or under heating conditions.

Evolved Gas Analysis by Mass Spectrometry

The intensities and relative energies of metal K pre-edge features are sensitive to both geometric and electronic structures. With the possibility to collect high-resolution spectral data it is important to find theoretical methods that include all important spectral effects: ligand-field splitting, multiplet structures, 3d–4p orbital hybridization, and charge-transfer excitations. Here the restricted active space (RAS) method is used for the first time to calculate metal K pre-edge spectra of open-shell systems, and its performance is tested against on six iron complexes: [FeCl6]n−, [FeCl4]n−, and [Fe(CN)6]n− in ferrous and ferric oxidation states. The method gives good descriptions of the spectral shapes for all six systems. The mean absolute deviation for the relative energies of different peaks is only 0.1 eV. For the two systems that lack centrosymmetry [FeCl4]2−/1−, the ratios between dipole and quadrupole intensity contributions are reproduced with an error of 10%, which leads to good descriptions of the integrated pre-edge intensities. To gain further chemical insight, the origins of the pre-edge features have been analyzed with a chemically intuitive molecular orbital picture that serves as a bridge between the spectra and the electronic structures. The pre-edges contain information about both ligand-field strengths and orbital covalencies, which can be understood by analyzing the RAS wavefunction. The RAS method can thus be used to predict and rationalize the effects of changes in both the oxidation state and ligand environment in a number of hard X-ray studies of small and medium-sized molecular systems.

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Simulations of iron K pre-edge X-ray absorption spectra using the restricted active space method.

The analytical applications of the evolved gas analysis (EGA) performed by infrared spectroscopy, for the period extending from 2005 to 2009, are collected in this review. By this technique, the nature of volatile products released by a substance subjected to a controlled temperature program are on-line determined, with the possibility to prove a supposed reaction, either under isothermal or under heating conditions.

Evolved Gas Analysis by Infrared Spectroscopy

A tetrachlorocobaltate(II) salt with 2-amino-5-picolinium: Synthesis, theoretical and experimental characterization

A correct interpretation for the mechanism of a thermally induced reaction, involving the formation of gaseous species, is strongly dependent on the characterization of the evolved products.The analytical applications of evolved gas analysis (EGA) performed by infrared spectroscopy (IR-EGA) for the period 2010–2012 are reviewed in this article. When the nature of volatile products released by a substance subjected to a controlled temperature program were determined on-line, the results proved a supposed reaction, under either isothermal or heating conditions.

Recent Applications of Evolved Gas Analysis by Infrared Spectroscopy (IR-EGA)

The crystal structure of tetraethylammonium tetrachloridoferrate(III) was determined. The crystals are hexagonal, space group P63
 mc, a = 8.198(1) A, b = 8.198(1) A, c = 13.183(3) A, V = 767.3(2) A3, Z = 2. The asymmetric unit of [(C2H5)4N][FeCl4] consists of half each of a tetraethylammonium cation and a tetrachloridoferrate(III) anion. Tetrachloridoferrate(III) ion adopts almost ideal tetrahedral geometry. Structural characterization of the compound is supplemented by the results of its magnetic susceptibility measurements and electron paramagnetic resonance (EPR) spectra. Magnetic measurements of a powdered [(C2H5)4N][FeCl4] sample gave a negative Weiss constant of −1.57, which suggests antiferromagnetic coupling. The susceptibility curve of [(C2H5)4N][FeCl4] against temperature exhibits a maximum, indicating the presence of antiferromagnetic ordering with a Neel temperature of approximately 2.9 K.

Structural and physico-chemical characteristics of tetraethylammonium tetrachloridoferrate(III)

Thermal decomposition of compounds consisting of tetrahalogenocuprate(II), [CuBrnCl4−n]2− (n=0–4) anions and a tetraethylammonium cation has been studied using TG-FTIR, TG-MS, DTA and DTG techniques. The measurements were carried out in an argon and air atmospheres over the temperature range 293-1073 K. The products of the thermal decomposition were identified by IR and Far Infrared (FIR) spectroscopy as well as X-ray powder diffractometry.

Thermal analysis of copper(Ii) complexes of general formula [Et4N]2[CuBrnCl4-n]

Thermal analysis of bis(tetraethylammonium) tetrachloroferrate(II)

The crystal structures of tetrabromocobaltate(II) and tetrabromomanganate(II) salts of general formula [(C2H5)4N]2[CoBr4] (1) and [(C4H9)4N]2[MnBr4] (2) were determined. The manganese and cobalt cations are four-coordinated by bromide anions and they adopt a slightly distorted tetrahedral coordination. In the structure of both compounds there are neither hydrogen bonds nor any unusual short-range intermolecular interactions. Magnetic measurements of the powdered samples gave negative values of the Weiss constants equal to −4.9 and −1.1 K for (1) and (2), respectively, which suggest antiferromagnetic interactions to be transferred within the crystal lattice.

Bis(tetraethylammonium) tetrabromocobaltate(II) and bis(tetrabutylammonium) tetrabromomanganate(II): structure and magnetic properties

Thermal decomposition of tetrabutylammonium bromotrichloro-, tribromochloro-and tetrabromoferrates(III), of general formula [(n-C
 4H9)4N][FeBr4−nCln] (n = 0, 1, 3), has been studied using the TG-MS, DTA, DTG as well as DSC techniques. The measurements were carried out in an argon atmosphere over the temperature range 293–1073 K. Solid products of the thermal decomposition were identified by X-ray powder diffractometry.

Emilia Styczeń

Papers

Structural and physico-chemical characteristics of tetraethylammonium tetrachloridoferrate(III)

Thermal analysis of copper(Ii) complexes of general formula [Et4N]2[CuBrnCl4-n]

Thermal analysis of bis(tetraethylammonium) tetrachloroferrate(II)

Bis(tetraethylammonium) tetrabromocobaltate(II) and bis(tetrabutylammonium) tetrabromomanganate(II): structure and magnetic properties

Thermal properties of tetrabutylammonium bromotrichloro-, tribromochloro-and tetrabromoferrates(III)