title: Conjugated BODIPY DYEmers by metathesis reactions.
abstract: Boron dipyrrin (BODIPY) DYEmers bridged by conjugating ethynylene and ethenylene moieties can be prepared through metal-promoted metathesis reactions. Alkyne metathesis was advantageous over alkene metathesis and Stille coupling for BODIPY substrates, but also showed specific restrictions with respect to steric encumbrance and regioselectivity. All derivatives with unhindered rotations along the bridges reside in a coplanar minimum conformation. For a hindered β-ethenylene-bridged DYEmer, the shifts in the (1) H NMR spectrum indicate a significant loss of coplanarity and conjugation. The electronic interactions of the BODIPY subchromophores, visualized by optical spectra and cyclic voltammograms, deviate significantly from those found for nonconjugated and excitonically coupled DYEmers. The observed properties can be rationalized in each case by the respective strength of conjugation through the α or β position, the degree of coplanarity, and conformational dynamics.
authors: Institut für Anorganische und Analytische Chemie (IAAC), Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig (Germany), Fax: (+49) 531-391-5387.
authors: Johannes
authors: J
authors: Ahrens
authors: Birte
authors: B
authors: Haberlag
authors: Anne
authors: A
authors: Scheja
authors: Matthias
authors: M
authors: Tamm
authors: Martin
authors: M
authors: Bröring
keywords: BODIPY; DYEmers; dyes/pigments; metathesis; tetrapyrroles