Synthesis of novel photochromic pyrans via palladium- mediated reactions

• Christoph Böttcher,
• Gehad Zeyat,
• Saleh A. Ahmed,
• Elisabeth Irran,
• Thorben Cordes,
• Cord Elsner,
• Wolfgang Zinth and
• Karola Rueck-Braun

Beilstein J. Org. Chem. 2009, 5, No. 25, doi:10.3762/bjoc.5.25

• was investigated by time-resolved absorption spectroscopy in the picosecond time domain. Keywords: benzopyrans; chromenes; naphthopyrans; palladium-mediated coupling reactions; photochromism; Introduction Interest in photoswitchable chromophores for the material and life sciences has increased

• dramatically over the past decade [1]. In the past, naphthopyrans were primarily commercialized as components for photochromic ophthalmic eyeware [2][3][4][5]. Nowadays, basic research in material sciences tries to implement photoswitchable pyrans and related chromophores as functional parts in organo

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

• the cyclophane acting as a convenient scaffold, as demonstrated previously [18][19]. To avoid steric crowding and excessive distance between the chromophores, it seemed reasonable to select the rigid all-trans butadienyl tether as represented in compound 2 (see Figure 3). The synthesis, molecular

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

• Jiří Kulhánek,
• Filip Bureš and
• Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

• most important goals of modern material chemistry. Organic chemists steadily attempt to design and synthesize novel and well-defined organic push-pull systems with prospective applications as chromophores for nonlinear optics (NLO) [1][2][3][4][5], dyes [6], electronic and photonic devices [7][8

• ) between the donor (D = NR2, OR groups etc.) and the acceptor (A = NO2, CN groups etc.) is most commonly comprised of double and triple bonds, aromatic and heteroaromatic rings as well as their combinations [14][15][16][17][18][19]. A typical synthetic approach to CT chromophores involves either a stepwise