Synthesis and Photochromic Properties of Naphthopyran Dimers | ||
| Egyptian Journal of Chemistry | ||
| Article 32, Volume 64, Issue 12, December 2021, Pages 7175-7180 PDF (334.68 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejchem.2021.89556.4303 | ||
| Authors | ||
| Hamad Elsehaibani1; Sherif Ragab* 2; Shaban Elkhabiry2 | ||
| 1Department of Chemistry, College of Science, Qassim University | ||
| 2National Research Centre | ||
| Abstract | ||
| We realized the synthesis of 2H-naphtho[1,2-b]pyran derivatives with substituents of halo, methyl at 6-position and/or, methyl, cyclopropyl, aryl at the 2-position in addition to three different spironaphtho[1,2-b]pyran derivatives with terpene substituents at the 2-spiro position of the pyran ring. The prepared naphtho[1,2-b]pyran derivatives 1a-c,2a-c,3a-c were subjected to dimerization in acetic acid with a few drops of concentrated sulfuric acid affording the corresponding dimers 4a-i. The structures of the dimers were confirmed based on the spectral tools (especially nuclear magnetic resonance). On exposure of the produced dimers to unfiltered light, a change from colorless to color state was observed. The effect of the substituent nature at the 2- or 6-positions of dimers on the photochromic properties and thermal fade characteristics was investigated | ||
| Keywords | ||
| Photochromism; naphthopyrans; irradiation; dimerization | ||
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