Synthesis and characterization of meso- tetraphenylporphinatochromium (II) and meso- tetrakis(4-cyanophenyl)prophinatochromium(II)complexes
การศึกษาวิธีการสังเคราะห์และโครงสร้างของ meso- tetraphenylporphinatochromium (II) complex และ meso- tetrakis(4-cyanophenyl)prophinatochromium(II)com-plexes
Radchada Buntem, D. of Chemistry, F. of Sci., Silpakorn U., Bangkok
Narongsak Chaichit, D. of Physics, F. of Sci. and Tech., Thammasart U., Bangkok
Uncharee Tooptakong, D. of Chemistry, F. of Sci., Silpakorn U., Bangkok
Laddawan Pdungsap, D. of Chemistry, F. of Sci., Mahidol U., Bangkok
Chaveng Pakawatchai, Asst. Prof., D. of Chemistry, F. of Sci., PSU.
Corresponding e-mail : radchada@su.ac.th
Presented : The 26th Congress on Science and Technology of Thailand, 18-20 October 2000,
Bangkok
Key words : porphyrin, metalloporphyrin, chromiumporphyrin complex
meso- tetraphenylporphyrin (TPP) was synthesized by refluxing benzaldehyde and pyrrole in propionic acid for 30 minutes. While meso- tetrakis(4-cyanophenyl)porphyrin (TCNPP) was made in a similar manner using 4-cyanobenzaldehyde as a source of aldehyde. Both ligands were obtained in moderate yield. They were then refluxed with an excess amount of freshly prepared [Cr(CH3COO)2]2 in N,N-dimethylformamide for 30 minutes. meso- Tetraphenylporphinatochromium(II) (Cr(II)TPP) and meso- tetrakis(4-cyanophenyl)porphinatochromium(II) (Cr(II)TCNPP) were obtained in mode-rate yield. Single crystals of both compounds were grown by slow diffusion of methanol to the con-centrated solution in chloroform. The uv/visible spectrum of the crystallized Cr(II)TPP in chloroform shows l max at 421.6, 550 and 592.6 nm. While that of Cr(II)TCNPP shows l max at 421.2 and 548.0 nm. 1H-NMR spectrum of Cr(II)TPP in deuterated chloroform exhibits two singlet signals at d 1.48 and
8.95 ppm and two multiplet signals at d 7.75 and 8.22 ppm. The molecular ion peak of Cr(II)TPP determined by fast atomic bombardment (FAB) mass spectrometry was found at 696. The result from single crystal X-ray diffraction shows that meso- tetraphenylporphinatochromium(II) has one methanol molecule solvated to Cr(II) in the axial vacant site.
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