Tetrahedral Boron Chemistry for the Preparation of Highly Efficient “Cascatelle” Devices

Citations Over TimeTop 10% of 2006 papers

Abstract

The replacement of the two fluorine atoms on the boron center of the well-known Bodipy fluorophore by functionalized acetylenic groups opens the way to a new family of highly luminescent, redox active, and stable fluorophores termed "E-Bodipy" species. The substitution is effective for ethynyl-lithium reagents incorporating tolyl, naphthyl, pyrenyl, fluorenyl, and terpyridinyl units. The protocol also tolerates the presence of various functional groups in the dipyrromethene meso position such as pyrene, phenylethynylpyrene, 4'-terpyridine, and iodophenyl. The last of these is particularly useful for a further coupling reaction enabling introduction of a flexible arm bearing a succinimidyl unit reactive toward primary amines. X-ray structure determinations of two E-Bodipy compounds confirm the introduction of the ethynyl units and show the boron atoms to have a distorted tetrahedral environment, with B-C(ethynyl) approximately 1.59 A and both boron atoms lying essentially in the mean planes of the dipyrromethene units. All the new compounds show intense electronic absorption bands (epsilon 60,000-70,000 M-1 cm-1), high quantum yields (>80%), and slow rates of nonradiative decay. Absorption by the aromatic substituents results in a "cascatelle" process leading to emission exclusively through the boradiazaindacene entity and thus large virtual Stokes' shift (>10,000 cm-1). The new compounds are also redox active, with the formation of both Bodipy+* and Bodipy-* occurring more readily than for F-Bodipy species. The molecules in their excited states are strong reducing agents.

Related Papers

• → Facile functionalization of a fully fluorescent perfluorophenyl BODIPY: photostable thiol and amine conjugates(2011)48 cited
• → Cyclopropyl Substituents Transform the Viscosity-Sensitive BODIPY Molecular Rotor into a Temperature Sensor(2021)40 cited
• → Effect of substituents on Stokes shift of BODIPY and its application in designing bioimaging probes(2018)38 cited
• → Recent Advances of the Near-infrared Fluorescent aza-BODIPY Dyes(2016)36 cited
• Solid state emissive bodipy dyes with bulky substituents as spacers and a sensitive and selective ratiometric near IR fluorescent probe for zinc ions based on the distyryl-bodipy fluorophore(2010)