BCl₃-Activated Synthesis of COO-BODIPY Laser Dyes: General Scope and High Yields under Mild Conditions

Abstract

A general and straightforward method for the synthesis of COO-BODIPYs from F-BODIPYs and carboxylic acids is established. The method is based on the use of boron trichloride to activate the involved substitution of fluorine, which leads to high yields through rapid reactions under soft conditions. This mild method opens the way to unprecedented laser dyes with outstanding efficiencies and photostabilities, which are difficult to obtain by the current methods.

A Computational-Experimental Approach to Unravel the Excited State Landscape in Heavy-Atom Free BODIPY-Related Dyes

“…Time-delayed emissions were also recorded from BODIPYs functionalized at their boron atom, such as COO- and N -BODIPYs (see 1 – 3 and 4 , respectively, in Scheme 1 ), the former involving two acyloxyl moieties grafted at the boron center [ 39 , 40 ], the latter bearing 4-methylbenzenosulfonamide functional groups replacing the fluorine atoms [ 41 ]. In addition, the BOPHY family (BODIPY-like fluorophores which have a central hydrazine-based spacer in the chelating ligand) was also tested (see dye 5 in Scheme 1 ) [ 42 ].…”

“…Commercial BODIPY dyes (PM546, PM567, PM597, PM605 and PM650 in Scheme 1 ) were purchased from Exciton Luxottica (Lockbourne, OH, USA) (laser grade) and were used as received without further purification. The at-boron modified COO - ( 1 – 3 ) and N -BODIPYs ( 4 ), as well as the BOPHY ( 5 ), of Scheme 1 , were synthetized by us, and the corresponding synthetic details and characterization were previously reported [ 39 , 40 , 41 , 42 ].…”

Substitution at boron in BODIPYs

“…63 More recently, a milder and higher yielding synthesis of COO-BODIPYs was reported (Scheme 8). 64 This involved activation of F-BODIPYs with BCl 3 , and was applied to a range of mono- and bis-carboxylic acids. This approach enabled chiral auxiliaries to be appended at boron, leading to COO-BODIPYs that exhibited circularly polarized luminescence in the visible region.…”

Synthesis and photophysical properties of novel oxadiazole substituted BODIPY fluorophores

“…BODIPY molecules exhibit strong molar extinction coefficient values (e) of absorbance, high fluorescence quantum yield and excellent chemical and photostability. [1][2][3] Due to their properties, these compounds are widely used in organic light-emitting diodes, [4][5][6][7][8][9] as laser dyes, [10][11][12][13][14] as fluorescent labels in bioimaging, [15][16][17][18][19] as indicator dyes in sensory applications, 20,21 in dye-sensitized solar cells [22][23][24] and many more. 25 The BODIPY moiety has also been studied for modification and use as a photosensitizer with applications in photodynamic therapy.…”