title: Isocyanate-, isothiocyanate-, urea-, and thiourea-substituted boron dipyrromethene dyes as fluorescent probes.
abstract: Boron dipyrromethene dyes (Bodipy) bearing a meso-phenyl substituent carrying a variety of functional groups can be prepared under mild conditions. A single-crystal X-ray structure determination for the 3,5-dinitrophenyl compound shows the phenyl ring to be almost orthogonal (dihedral angle 84 degrees) to the plane of the Bodipy core, with one nitro group almost coplanar with the ring and the other tilted by approximately 21 degrees. Nitro substituents at the 3-, 4-, and 5- positions of the phenyl group are readily reduced to the corresponding amino groups and then converted to isocyanato, isothiocyanato, urea, thiourea, and some polyimine derivatives, the last providing additional functionality (phenazine and pyridylindole units) suitable for chelation of metal ions. All compounds are redox active, the electron-transfer processes being assigned on the basis of comparisons with model compounds. Their fluorescence properties are sensitive to the phenyl group substituents. The Bodipy unit excited state appears to be a strong reductant (Eo approximately -1.4 V) and a modest oxidant (Eo approximately +1.0 V). Quenching processes in the nitro and phenazine derivatives appear to involve intramolecular photoinduced electron transfer.
authors.affiliation: Laboratoire de Chimie Moléculaire, Ecole de Chimie, Polymères, Matériaux, Université Louis Pasteur, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France. ziessel@chimie.u-strasbg.fr
authors.forename: Raymond
authors.initials: R
authors.lastname: Ziessel
authors.forename: Laure
authors.initials: L
authors.lastname: Bonardi
authors.forename: Pascal
authors.initials: P
authors.lastname: Retailleau
authors.forename: Gilles
authors.initials: G
authors.lastname: Ulrich
mesh_terms: D001895:Boron / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D017953:Isocyanates / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011162:Porphobilinogen / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D012996:Solutions; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature; D014508:Urea / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D017953:Isocyanates; D012996:Solutions; D013438:Sulfhydryl Compounds; C507544:dipyrromethene; D011162:Porphobilinogen; D014508:Urea; D001895:Boron