Thermal Decomposition Mechanism of Sr(DPM)[sub 2]

Abstract

The thermal decomposition behavior of Sr(DPM) 2 (DPM: 2,2,6,6-tetramethyl-3,5-heptadionate, C 11 H 19 O 2 ) was studied using thermogravimetry, mass, UV, and in situ infrared spectroscopy. In particular, dissociation of the chemical bonds in the complex ligand has been studied by monitoring the change in the intensity of the IR peaks while the sample is heated. The decomposition behavior of Sr(DPM) 2 is sensitive to the ambient gases and the Sr complex is severely degraded after storage for a year. The chemical bonds in the complex begin to be dissociated at low temperatures and are sequentially decomposed at elevated temperatures. The Sr-O and the C-C(CH 3 ) 3 bonds dissociate most easily, then the C-H bond, while the C-O and the C-C bonds are stable up to high temperatures. Decomposition of the Sr complex is enhanced when it is exposed to O 2 because removal of the tert-butyl group from the ligand skeleton facilitates the Sr-O bond dissociation. Compared with the Ti-O bond in Ti(O-iPr) 2 (DPM) 2 , the Sr-O bond is easily dissociated due to its ionic bond character as confirmed by UV spectroscopy. Removal of the tert-butyl group and dissociation of the Sr-O bond trigger oligomerization of the Sr compound so that a large amount of carbonate residue is obtained at high temperatures.

Synthesis and characterization of Sm(DPM)3 used as precursor for MOCVD

“…Hence, the ligand structure becomes more flexible, resulting in an increase of the coupling of C-C vibrational modes, and then the intensity of the peaks for C-C bonds enhances at around 1540 cm À1 as observed from 270 C to 325 C, which was also reported by Hyun-kyu Ryu et al [23]. The peaks for C-C disappear up to 400 C due to excessive temperature.…”

“…A wide peak in the range of 315-415 C represents the formation of Sm 2 (CO 3 ) 3 as confirmed by IR analysis of the sample afterwards, which also corresponds with the large decomposition endothermic peak at 406 C in the DTA-curve in air; hence the residue at 450 C increases to 10.5% of the initial weight. Comparing the two DTA-curves, it can be found that the last two peaks of the sample decrease by about 25 C and 19 C, respectively, in air, which is due to the fact that the ample O 2 and CO 2 in air facilitate the decomposition and oxidation of the sample according to the result of Sr(DPM) 2 by HyunKyu Ryu et al [23]. The great diversity of both second endothermic peaks existed in N 2 and air demonstrates that the peak represents the partial decomposition process rather than melting of sample.…”

Synthesis of Heteroleptic Strontium Complexes Containing Substituted Cyclopentadienyl and β-Diketonate Ligands

“…(1) and 475 cm −1 (2) which was assigned as Sr−O bond stretching vibrations 16 and confirmed the presence of tmhd in the compound. The strong peaks at 1589 cm −1 (1) and 1600 cm −1 (2) were C−C partial double bond as well as from the C−O partial double bond of tmhd ligand of the complexes.…”

Synthesis of Strontium Oxide Whiskers with Preferential <111> Orientation by Atmospheric Chemical Vapor Deposition

“…Sr(DPM) 2 decomposes at temperatures above 200 ℃ under N 2 (Ryu et al, 2000). The Sr(DPM) 2 conditions in this study had a melting point of 210 ℃ and a boiling point of 231 ℃ (at 13.3 Pa).…”