Donor-acceptor (D-p-A) dyestuff and colorants represent a vast majority of organic chromogens. Such compounds have found many applications such as in dyeing of fabric, coloring of toners, and in image forming and optical information storage technologies. Some of these compounds are also used as sources of tunable (dye laser) radiation [1,2,3].
Recently, we synthesised a series of benzylidenes based on cyclopentanone and its cyclpentylidene malononitrile condensate [4]. In this paper, we report the synthesis of (2E)-2-(2,4,6-trimethoxy-benzylidene)indan-1-one (3) [5] as a candidate donor-acceptor conjugated dye for possible applications in third order nonlinear optics.
2,4,6-Trimethoxybenzaldehyde (2.0 g, 0.01 mol) and 1-indanone (1.34 g, 0.01 mol) were dissolved in 25 ml of ethanol and then heated to boiling before sodium hydroxide (10 ml, 0.10 M) was added. The reaction mixture was refluxed for 3 h, cooled and then the precipitate was filtered and recrystallized from ethanol.
m.p. 185 °C
Yield: 68%
Color: Yellow crystals
IR; ν (cm-1): 2934 (C–H),1685 (C=O), 1134 (C–O).
1H NMR;(DMSO-d6, 400 MHz ): 7.90 (d, 1H, J = 8.0 Hz, Haromatic), 7.83 (s, 1H, olefinic H), 7.57 (t, 1H, J = 7.6 Hz, Haromatic), 7.46 (d, 1H, J = 7.6 Hz, Haromatic), 7.37 (t, H, J = 7.6 Hz, Haromatic), 6.20 (s, 2H, Haromatic), 3.89 (s, 9H, OMe), 1.71 (s, 2H, CH2).
Elemental analysis: Calculated for C19H18O4: C, 73.53%, H, 5.85%; Found: C, 73.68%, H, 5.91%
Supplementary materials
Supplementary File 1Supplementary File 2Supplementary File 3Acknowledgements
The authors would like to thank King Abdul Aziz City of Science and technology for the financial support through the grant No. At-24-72.
References and Notes
- Fabian, J.; Hartmann, H. Light Absorption of Organic Colorants; Springer Verlag: Berlin, 1980. [Google Scholar]
- Asiri, A. M. Synthesis and characterization of dyes exemplified by 2-arylidene-1-dicyanomethyleneindane. Dyes and Pigments 1999, 42, 209. [Google Scholar] [CrossRef]
- Attia, A.; Michael, M. Azachalcones. Part 2: Reactions of 3,3-diazachalcones. Pharmazie 1982, 37, 551. [Google Scholar] [PubMed]
- Asiri, A. M. Synthesis and Absorption Spectral Properties of Bis-methine Dyes Exemplified by 2,5-Bis-arylidene-1-dicyanomethylene-cyclopentanes. Bull. Korean Chem. Soc. 2003, 24, 426. [Google Scholar] [CrossRef] [Green Version]
- The title compound was obtained as a single isomer, accotrding to TLC; assignment of the E configuration is based on the chemical shift (7.83 ppm) of the olefinic proton.
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