Photochromic thiophenefulgides. Photokinetics of two isopropyl derivatives
1991; Elsevier BV; Volume: 154; Issue: 2 Linguagem: Inglês
10.1016/0301-0104(91)80081-r
ISSN1873-4421
AutoresK. Ulrich, H. Port, Hans Christoph Wolf, Johann Wonner, Franz Effenberger, Hans‐Dieter Ilge,
Tópico(s)Organic Chemistry Cycloaddition Reactions
ResumoFor two photochromic isopropyl-thiophenefulgides a complete photokinetic analysis is given. For one compound (5b), the partial quantum yield for the colouring process (ΦEC = 54%) is the highest value found for thiophenefulgides. EZ-isomerisations do not play an important role. The colouring quantum yield is temperature independent down to 20 K, whereas bleaching requires little thermal activation. In case of an adamantylidene substituted isopropyl-thiophenefulgide (5c), the bleaching efficiency (ΦCE = 31%) is very high. Upon heating of the cyclic products, thermal bleaching occurs with an activation energy of 1 eV.
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