Synthesis, characterization and thermal behaviour of solid-state compounds of benzoates with some bivalent transition metal ions

Abstract

Recebido em 10/11/05; aceito em 25/5/06; publicado na web em 24/10/06Solid-state MBz compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu and Zn and Bz is benzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The procedure used in the preparation of the compounds via reaction of basic carbonates with benzoic acid is not efficient in eliminating excess acid. However the TG-DTA curves permitted to verify that the binary compounds can be obtained by thermosynthesis, because the benzoic acid can be eliminated before the thermal decomposition of these compounds. The results led to information about the composition, dehydration, thermal stability, thermal decomposition and structure of the isolated compounds. On heating, these compounds decompose in two (Mn, Co, Ni, Zn)

Synthesis and magnetic studies of copper(II)-lanthanide(III) 5-bromosalicylideneglycylglycine

“…In the spectra of complexes, additional bands of medium intensity occur in the 556-560 cm -1 region and may be assigned to the metal-oxygen vibration. Therefore, the metal ions in these complexes may be bridged by ligands coordinating through the oxygen atoms [18][19][20][21][22][23][24].…”

Exceptionally slow magnetic relaxation in cobalt(ii) benzoate trihydrate

“…A similar procedure but followed by evaporation to dryness and using cobalt(II) basic carbonate led to the isolation of the anhydrous compound in the form of a microcrystalline powder. 8 Alternatively, the anhydrous cobalt(II) benzoate (its monoclinic form) was prepared by the reaction of cobalt(III) acetylacetonate with benzoic acid in the melt (150°C), 9 or by the reaction of cobalt(II) nitrate with benzaldehyde in air yielding, depending on the temperature, the monoclinic or orthorhombic form of anhydrous cobalt benzoate. 10 The resulting single crystals of 1 were characterized chemically and spectroscopically.…”

“…In search of new systems within the broad class of single molecule magnets (single ion magnets, single chain magnets) we have prepared cobalt(II) benzoate trihydrate, [Co(Bz)(H 2 O) 2 ] Bz•H 2 O (1), in single crystal form and elucidated its chain-like crystal structure. Several reports on the syntheses, properties and structures of cobalt(II) benzoate in the anhydrous form, [8][9][10] as the dihydrate 11 or as the tetrahydrate, 11,12 have been published, but to our knowledge no report on the trihydrate has been published so far. The magnetic properties of the two forms of anhydrous cobalt(II) benzoate were also studied.…”

Thermal decomposition of solid state compounds of lanthanide and yttrium benzoates in CO2 atmosphere

“…A survey of literature shows that the complexes of rare earth elements with benzoic acid and some of their derivatives have been investigated in aqueous solutions [1][2][3][4][5] and in solid state [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”