Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• concentration, no intermolecular reaction could compete with an intramolecular process [12]. Disappearance quantum yields at 394 nm were found to be low in methylcyclohexane (1.5 × 10−4) and in acetonitrile (4.2 × 10−2). The weakness of the cyclophotoaddition probably reflects a preference for internal

• balance (sensitivity 10−7 g). Quantum yields Reaction quantum yields were determined as described elsewhere [29], using the Parker iron trioxalate actinometer. The monochromatic beams were obtained from a cooled 1000 W Xenon lamp, using a Bausch and Lomb monochromator. The samples were previously purged

Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation

• Ivana Kosiova,
• Andrea Janicova and
• Pavol Kois

Beilstein J. Org. Chem. 2006, 2, No. 23, doi:10.1186/1860-5397-2-23

• ), which were synthesised in our department as part of studies into new ligands. Coumarins as fluorescent probes or labels [28][29][30] have extensive and diverse applications, they exhibit extended spectral range, are photostable and have high emission quantum yields. Ferrocene derivatives are often used