Thermal and spectroscopic studies of scandium complex of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone
- 作者：Yoshifumi Akama ; Tadanobu Sawada and Toyotoshi Ueda
- 关键词：Sc(PMBP)3 ; Facial and meridional isomers ; 1H NMR ; Thermal analysis
- 刊名：Journal of Molecular Structure
- 出版年：2005
- 期刊代码：62_00222860
- 类别：ch
- 出版时间：2005
- 卷：750
- 期：1-3
- 页码：44-50
- 文件大小：306 K
摘要
The scandium complexes of Sc(PMBP)3·H2O (non-crystal) and Sc(PMBP)3 (crystal) with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) were prepared and characterized by thermal analysis, IR, NMR and MS spectroscopies. The crystal structure of the complex, obtained by X-ray analysis, indicates that PMBP is a bidentate ligand in the complex and that the Sc atom is six-coordinate and is in a meridional octahedral environment. The order of the ring current effect on the pyrazolone ring is Sc(PMBP)3 >PMBP(enol)> PMBP(keto).
The metal to ligand stoichiometry was found to be 1:3. The crystalline complex melts at 209 °C, followed by degradation at about 310 °C, with the beginning of decomposition. The enthalpy of melting was found to be 61 kJ/mol. On the other hand, the non-crystalline complex was found to change into a crystalline complex at 176 °C with an exothermic reaction before melting at 217 °C. The IR band observed at approximately, 450 cm−1 is possibly due to the stretching of the Sc–O bond.