Degradation of Ba(DPM)2 during storage in a desiccator for extended periods

Ryu, Hyun-Kyu; Heo, Jung Shik; Cho, Sung-Il; Cho, Yong Suk; Moon, Sang Heup

doi:10.1007/bf02698350

Cited by 4 publications

(4 citation statements)

References 13 publications

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“…Because ions of alkaline-earth metals such as barium and strontium have relatively large radii and low charge-to-size ratios, they combine easily with CO 2 and moisture in the air to form stable complexes of saturated coordination. 13,14 We have recently investigated the degradation mechanism of Ba(DPM) 2 using TG analysis, FTIR, and MS, 15 and have confirmed that the FTIR spectra of aged Ba(DPM) 2 change in accordance with the degradation mechanism of Sr(DPM) 2 proposed in this study. The IR results 15 showed that the peak due to (C-O) with the fresh sample was converted to a new peak corresponding to free (CϭO) with the aged samples, indicating that the bond between the Ba ion and the ligand ring is dissociated during the storage.…”

Section: Resultssupporting

confidence: 80%

“…13,14 We have recently investigated the degradation mechanism of Ba(DPM) 2 using TG analysis, FTIR, and MS, 15 and have confirmed that the FTIR spectra of aged Ba(DPM) 2 change in accordance with the degradation mechanism of Sr(DPM) 2 proposed in this study. The IR results 15 showed that the peak due to (C-O) with the fresh sample was converted to a new peak corresponding to free (CϭO) with the aged samples, indicating that the bond between the Ba ion and the ligand ring is dissociated during the storage. Furthermore, the peaks corresponding to the vibrational modes of HDPM (2,2,6,6tetramethyl-3,5-heptanedione) became significant with the aged sample.…”

Section: Resultssupporting

confidence: 80%

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

Ryu¹,

Heo²,

Cho³

et al. 2000

J. Electrochem. Soc.

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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.

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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 80%

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

Ryu¹,

Heo²,

Cho³

et al. 2000

J. Electrochem. Soc.

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“…3, these absorption peaks decreased or disappeared, and peaks at 1700 cm ±1 , corresponding to the C=O bond, appeared. [10] This result shows that the molecular structure of the residue differed from that of the as-received sample. Table 2 shows the results of the compositional analysis of the same samples shown in Figure 6.…”

Section: Introductionmentioning

confidence: 63%

Thermal Stability of Pb(C11H19O2)2 Used as the Lead Source in MOCVD

Nagashima

Funakubo

Seki

et al. 2000

Chem. Vap. Deposition

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The thermal stability of lead bisdipivaloylmetanate [Pb(C 11 H 19 O 2 ) 2 ], used as a Pb source for the organometallic precursor in the metal±organic chemical vapor deposition MOCVD preparation of Pb-based ferroelectric films, was investigated. Using thermogravimetry differential thermal analysis (TG-DTA), with a heating rate of 10 K min ±1 and nitrogen as the carrier gas, the as-received specimen showed endothermic peaks at 132 C, and complete evaporation by 300 C. Isothermal mass loss analysis showed that, in the temperature range 100 C to 200 C, no degradation of the sample occurred. The specimen remained unchanged after being heated at 150 C for 1800 h in a sealed vessel. On the other hand, degradation occurred during the actual MOCVD process over 1500 h at 150 C. This decomposition was temperature dependent as no degradation was detected under CVD operating conditions over 2400 h at 140 C. Under CVD operating conditions, at 150 C, Pb(C 11 H 19 O 2 ) 2 continuously decomposed, decomposition products with a higher vapor pressure forming in the source container. Therefore, this decomposition is a characteristic feature of the MOCVD process in which the carrier gas flows through the source container.

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“…There are discrepancies in temperatures initiating the weight loss and the amounts of residue obtained at high temperatures between this study and our previous report, 19 which possibly arises from different storage histories of the commercial samples. 20 Nevertheless, we have used the present result because the purpose of this study is to compare the decomposition behavior of three different Sr compounds, particularly correlated with the glyme adducts.…”

Section: Resultsmentioning

confidence: 99%

Thermal Decomposition Mechanism of Bis(dipivaloylmethanato)strontium Compounds Containing Glyme Adducts

Cho

Ryu

et al. 2003

J. Electrochem. Soc.

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The mechanisms of the thermal decomposition of Sr͑dpm͒ 2 , Sr͑dpm͒ 2 -triglyme, and Sr͑dpm͒ 2 -tetraglyme, where Sr͑dpm͒ 2 is bis͑dipivaloylmethanato͒strontium, were examined using thermogravimetric analysis, mass spectrometry, and Fourier transform infrared spectroscopy ͑FTIR͒. The chemical bonds in the Sr compounds are sequentially decomposed as the compounds are heated. That is, glyme adducts are decomposed at temperatures below 200°C, and the Sr-O and the C-C(CH 3 ) 3 bonds are dissociated at higher temperatures, whereas the C-O and the C-C bonds remain stable at temperatures up to 400°C. Glyme adducts in the Sr compounds weaken the Sr-O bond between the central Sr atom and the dpm ligand, and, as a result, the Sr-O bond in Sr͑dpm͒ 2 -glymes is dissociated at lower temperatures than the bond in Sr͑dpm͒ 2 . However, Sr͑dpm͒ 2 -glymes are more effectively protected from degradation, thus yielding smaller amounts of residues at elevated temperatures than Sr͑dpm͒ 2 . The FTIR results suggest that a fraction of the dissociated glyme species remains bonded to the Sr compound such that the bonded species suppresses the flexibility of the dpm ligand and consequently, access of other molecules to the central Sr atom. Sr͑dpm͒ 2 -triglyme is stabilized by glyme adducts more effectively than Sr͑dpm͒ 2 -tetraglyme, which is thought to originate from different numbers of oxygen atoms coordinated with the Sr atom between the two compounds.

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Degradation of Ba(DPM)2 during storage in a desiccator for extended periods

Cited by 4 publications

References 13 publications

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

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

Thermal Stability of Pb(C11H19O2)2 Used as the Lead Source in MOCVD

Thermal Decomposition Mechanism of Bis(dipivaloylmethanato)strontium Compounds Containing Glyme Adducts

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