화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.297, 219-226, 1997
New Photochromic bis-Spirocyclic Systems
Novel photochromic bis-spirocyclic compounds, derivatives of di(4-cyclohexa-2,5-dien-1-one)benzimidazole 5a and di(4-cyclohexa-2,5-dien-1-one)perimidine 8a have been synthesized. Under UV-irradiation of their tol;ene solutions compounds 5a (lambda(max) = 474 - 502 nm) undergo thermally irreversible rearrangement to the isomeric bis-quinoneimines 5b (lambda(max) = 593 - 602 nm). When treated with trifluoroacetic acid in toluene 5a and 8a form monoprotonated cations 5aH(+) and 8aH(+)(lambda(max)=375 - 384 nm) which reveal photocromic properties. The photoisomers of the cations 5aH(+) and 8aH(+) possess long-wave absorption bands properties (lambda(max)=766 - 810 nm). Quantum yields fall into the range of 0.13-0.17.