The thermal behavior of triethylenediammonium salts - A combined investigation of (trienH(2))[CoCl4] and (trienH(2))(2)[(FeCl4)(2)(mu-C2O4)]center dot 2H2O using TG-MS, FT-IR, and Raman spectroscopy

(trienH(2))[CoCl4], which contains tetrahedral chlorocobaltate(II) anions, decomposes under argon in two stages via a stepwise deprotonation of the cation. The decomposition starts at 310 degrees C with the liberation of HCl, followed at 400 degrees C by the simultaneous release of a further mole of HCl and triene and/or its cracking products. The second decomposition stage is strongly influenced by the atmosphere. In the lower temperature region (< 400 degrees C), increasing oxygen contents of the carrier gas lead to decreasing mass losses. Therefore, the solid residues contain various amounts of C,N-containing products as well as cake. The thermal decomposition of the iron(III) compound, which contains mu-oxalato-bridged FeCl4 units, begins with the dehydratation followed by the decay of the complex anion to produce CO, CO2, and HCl. Instead of a binuclear, mono-oxobridged chloroferrate(III) complex, a [FeCl4](-)-containing compound is proposed as one of the final products. The third decomposition stage, partially overlaying the preceding one, is the degradation of the organic cation as found for the cobalt compound. The results of the in situ-TA-MS measurements are compared with those obtained from usual TA techniques as well as from the residue characterization by X-ray diffraction, Raman spectroscopy, and chemical analysis.