Three novel photoisomeric compounds of the 4-acyl pyrazolone derivants: Crystal structures and substituent effects on photo-isomerism in solid state

• 来源期刊: 中国科学B辑（英文版）
• 年，卷（期）: 2008,（7）
• 页码范围: 661-668
• 页数: 8页
• 语种: 英文
• DOI: 10.1007/s11426-008-0025-4

摘要

Three new photoisomeric compounds: 1,3-diphenyl-4-benzal-5-pyrazolone 4-methylthiosemicarbazone (DPBP-MTSC), 1,3-diphenyl-4-(4'-methylbenzal)-5-pyrazolone 4-methylthiosemicarbazone (DP4MBP-MTSC), and 1,3-diphenyl-4-(4'-bromobenzal)-5-pyrazolone 4-methylthiosemicarbazone (DP4BrBP-MTSC) were synthesized by direct condensation of pyrazolones and 4-methylthiosemicarbazone. Their struc-tures were confirmed using 1H NMR, IR, elemental analyses, and X-ray crystallographic analyses. The photoisomeric properties in the solid state were studied under UV light irradiation and the photo-isomerization phenomena were interpreted by the double proton-transfer mechanism. Moreover, the effects of different substituent groups at the 4-position of the benzal in the three compounds on the photoisomeric properties were discussed.