Synthesis, crystal structures, and photochromic properties of 6,6′ or 7,7′ or 6,7′-dimethyl-[2,2′-bi-1H-indene]-3,3′-diethyl-3,3′-dihydroxy-1,1′-diones

Synthesis and Properties of Brominated 6,6′‐Dimethyl‐[2,2′‐bi‐1H‐indene]‐3,3′‐diethyl‐3,3′‐dihydroxy‐1,1′‐diones

“…The lower melting point (180-182 (1) 155.8 (7) O(2)-C(5) 1.249(10) C(5)-C(9)-C(12) 121.9(8) C(10)-C(9)-C(12)-Br(2) -83.7(9) (2) 108.4(7) C(9)-C(10)-C(11)-C(4) 4.4(16) ℃) of 4 may be owing to the lack ofπ-π stacking interaction, and its crystal structure is defective tightness compared with compound 1 (269-271 ℃). 26 The melting point of compounds 2 (240-242 ℃) and 3 (261-262 ℃) are also lower compared to compound 1, this might be due to that in solid compounds 2 and 3, molecular arrange is not so tight compared with their precursor 1 although we have not obtained the single crystals of compounds 3 and 4. The inducement of this phenomenon is considerablely due to that the hydrogen atoms in the methyl groups on the benzene rings of biindenylidenedione are substituted by bromines.…”

“…For compounds 2 and 3, the absorption peak strength of long-wavelength band [λ max ＝338 nm (2), λ max ＝ 327.5 nm (3)] is more intense than that of short-wavelength band [λ max ＝234 nm (2), λ max ＝237 nm (3)], which is similar to their precursor compound 1. 26 While for compound 4, the absorption peak strength of long-wavelength band (λ max ＝319 nm) is less intense than that of short-wavelength band (λ max ＝239 nm). For short-wavelength band, from compound 2 to 4, the λ max increase in turn [234 nm (2), 237 nm (3), and 239 nm (4), respectively], and their λ max are longer than that of compound 1 (λ max ＝229.2 nm).…”

“…In order to explore the relationship between the structure and physical properties such as photochromic and photomagnetic ones, we have continuously made modifications on biindenylidenedione backbone, and prepared a series of biindenylidenedione derivatives. [21][22][23][24][25][26][27][28] Most of the structural modifications have been carried out on the five-membered rings of the biindenylidenedione, and the results showed that such modifications have a considerable effect on both photochromic and photomagnetic properties of this kind of molecules in the solid state. [22][23][24][25][26][27][28] At the same time, the attempts to introduce other substituents rather than hydrogen on the benzene rings in the biindenylidenedione have been made.…”

“…[21][22][23][24][25][26][27][28] Most of the structural modifications have been carried out on the five-membered rings of the biindenylidenedione, and the results showed that such modifications have a considerable effect on both photochromic and photomagnetic properties of this kind of molecules in the solid state. [22][23][24][25][26][27][28] At the same time, the attempts to introduce other substituents rather than hydrogen on the benzene rings in the biindenylidenedione have been made. For example, new methyl substituted biindenylidenedione derivatives dimethyl-[2,2'-bi-1H-indene]-3,3'-diethyl-3,3'-dihydroxy-1,1'-diones from 4methylphthalic anhydride have been successfully synthesized, 26 and their crystal structures and properties were also investigated.…”

“…[22][23][24][25][26][27][28] At the same time, the attempts to introduce other substituents rather than hydrogen on the benzene rings in the biindenylidenedione have been made. For example, new methyl substituted biindenylidenedione derivatives dimethyl-[2,2'-bi-1H-indene]-3,3'-diethyl-3,3'-dihydroxy-1,1'-diones from 4methylphthalic anhydride have been successfully synthesized, 26 and their crystal structures and properties were also investigated. The results reveal that the substituents, even like the simple methyl, on the benzene rings of biindenylidenedione could considerably affect the photochromic property, as well as other properties of this kind of compounds.…”