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Molbank 2002, 2002(1), M286;

Short Note
The Key Laboratory of Gene Engineering of Ministry of Education / Department of Chemistry, Zhongshan University, Guangzhou 510275, China
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
Author to whom correspondence should be addressed.
Received: 25 April 2002 / Accepted: 29 May 2002 / Published: 20 February 2003
polypyridine ligands; phenanthroline; benzil
Molbank 2002 m286 i001
1,10-Phenanthroline-5,6-dione was prepared by a previously published procedure [1]. The title compound was synthesized according to the method for the preparation of imidazole rings established by Steck and Day [2]. A mixture of 3,4-(methylenedioxy)benzaldehyde (8 mmol), 1,10-phenanthroline-5,6-dione (5 mmol), ammonium acetate (100 mmol) and glacial acetic acid (20 cm3) was refluxed with stirring at 130°C for about 1.5 hour, then cooled to room temperature and diluted with water (ca. 20 cm3). Dropwise addition of concentrated aqueous ammonia with stirring gave a yellow precipitate, which was filtered and washed with water and acetone. The crude product was purified by silica gel filtration (60-100 mesh, ethanol as eluent). The principal yellow band was collected. After most of the ethanol solvent was removed under reduced pressure, the amorphous yellow solid was filtered and washed with acetone and diethyl ester, then dried in vacuum. Yield 1.03 g, 58%.
Elemental analyses: Found C, 69.23; H, 3.64; N, 15.87. Calc. For C20H12N4O2×0.5H2O, C, 68.76; H, 3.75; N, 16.04.
1H NMR (500 MHz, (CD3)2SO): d 13.50 (br, s, 1H), 9.02 (dd, 2H), 8.90 (d, 2H), 7.85 (m, 2H), 7.80 (m, 2H), 7.12 (d, 1H), 6.19 (s, 1H).
IR (KBr, cm-1): 463 (w), 547 (w), 621 (m), 740 (s), 813 (s), 879 (m), 937 (m), 963 (m), 1036 (s), 1073 (m), 1116 (m), 1190 (w), 1225 (s), 1258 (s), 1350 (s), 1397 (m), 1437 (m), 1471 (s), 1500 (m), 1562 (m), 1604 (m), 2898 (w), 2963 (w), 3001 (w), 3066 (w), 3105 (w), 2688-3105 (br), 3423 (br, m).
FAB-MS ([M+1]+): 341, 50%.

Supplementary materials

Supplementary File 1Supplementary File 2Supplementary File 3


Support for this research provided by the National Natural Science Foundation of China and the National Science Foundation of Guangdong Province.


  1. Paw, W.; Eisenberg, R. Inorg. Chem. 1997, 36, 2287.
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