Synthesis of 8-substituted 4, 4-difluoro-4-bora-3a,4a-diaza-s-indacene Dyes (BODIPY) (original) (raw)
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Synthesis of 8-heteroatom-substituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene dyes (BODIPY)
Tetrahedron, 2006
Thioketones, bis-(5-R-1H-pyrrol-2-yl)-methanethiones (R¼H, Me, Et), 4 react with methyl iodide or isopropyl triflate to give the pyrrolium salts, which are treated with tertiary amine and boron trifluoride to produce the 8-(thiomethyl/thioisopropyl) 4,4-difluoro-3,5-di-R-4-bora-3a,4a-diaza-s-indacenes 6a-6c and 8a-8c. The reaction of the methyl thioether group of 6a and 6b with aniline gives the substitution products whose structure corresponds to formula 10. The structures of the thioethers 6a-6c and compound 10a were determined by X-ray diffraction. The thiomethyl groups in 6a-6c are close to be coplanar to the flat ring system, the strain due to the interaction of methyl with the hydrogen at C1 is released by shifting of the sulfur atom away from carbon C1 and opening of the angle C8-S-methyl. This coplanarity of the thiomethyl group with ring system agrees with the preference of the syn conformation of methyl vinyl thioether. In the structures of the aniline compound 10a the length of the nitrogen to C8 is close to that of N]C double bond. Thioethers 6a-6c show high wavelength absorption at 523-530 nm and fluorescence with a Stokes shift of 12-24 nm and with a quantum yield of 0.15-0.37. In contrast the aniline substituted compounds 10a and 10b showed absorption at 410 and 430 nm, respectively, with no fluorescence. According to their spectral properties they are better described by structure 10 than 7.
The Journal of Organic Chemistry, 2007
A straightforward method for the synthesis of original 4,4dialkoxy-or 4,4-diaryloxy-diaza-s-indacenes (BODIPY) derivatives obtained by treatment of BODIPY 1 with various alcohols in the presence of AlCl 3 is described. The novel compounds are characterized by spectroscopic properties similar to those of the parent BODIPY 1, absorption and emission spectra with similar band shapes, high molar absorption coefficients ( λmax ≈ 80 000 M -1 cm -1 ), and for most of them high fluorescence quantum yields (Φ exp from 0.52 to 0.71). Among all of the new compounds synthesized, the dye 2h exhibits higher fluorescence quantum yield (0.71) and lifetime (4.09 ns) than compound 1 and a good chemical stability toward conditions compatible with biological cellbased assays. 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes are highly fluorescent molecules 1 that have been used for a large number of applications. 2 Recently, we synthesized various BODIPY-labeled pirenzepine derivatives to investigate their binding to GFP-labeled muscarinic M1 receptors by fluorescence resonance energy transfer (FRET). 3 BODIPY dyes are commercially available 4 in small quantities suitable for biochemical experiments, but amounts typically required for synthetic organic chemistry are prohibitively expensive. Therefore, as part of our program to develop fluorescent combinatorial libraries to identify new ligands of orphan GPCRs by FRET, 5 we were interested in the synthesis of novel and readily accessible BODIPY-like fluorescent dyes.
Synthesis, Photophysical Properties and Solvatochromism of Meso-Substituted Tetramethyl BODIPY Dyes
The 4,4-difluoro-4-bora-3a,4a-diaza-s -indacene fluorescent dyes (BODIPYs) were first synthesized almost 50 years ago; however, the exploration of their technological application has only begun in the last 20 years. These dyes possess interesting photophysical properties, increasing interest in their application as fluorescent markers and/or dyes. Herein, we report the synthesis of tetramethyl BODIPY and four meso-substituted dyes (2-thienyl, 4-pyridinyl, 4fluorophenyl and 4-nitrophenyl derivatives). Their photophysical characterization (absorption spectra, emission spectra, fluorescence quantum yields and time-resolved fluorescence) and solvatochromic behavior were studied. Absorption and emission were barely affected by substituents, with a slightly higher stokes shift observed in the substituted dyes. Substitutions could be associated with a shorter fluorescence lifetime and lower quantum yields. Good correlations were observed between the Catalán solvent descriptors and the photophysical parameters. Also, better correlation was observed between the solvent polarizability descriptor (SP) and photophysical parameters. Overall, only slight solvatochromism was observed. The 4-pyridinyl derivative was the subject of a relatively significant solvatochromism regarding the wavelengths of the emission spectra, with the observation of a bathochromically shifted emission in methanol. The fluorescence quantum yield of the 4-nitrophenyl substituted BODIPY was approximately 30 times higher in hexane, which may be of interest for practical applications.
Functionalization of 3,5,8-trichlorinated BODIPY dyes
The Journal of organic chemistry, 2014
Catalytic hydrogenation of dibenzyl 5-dipyrroketone-2,9-dicarboxylates followed by decarboxylative iodination affords a 2,9-diiododipyrroketone which gives a 2,5,9-trichlorodipyrromethene hydrochloride after nucleophilic addition/elimination, with adventitious chloride to replace the two iodide groups. Treatment with BF3·Et2O gives a 3,5,8-trichloro-BODIPY that readily undergoes regioselective Stille coupling at the 8-position, or homo/mixed couplings at the 3,8- or 3,5- and 8-positions. Stepwise and controlled replacement of the 3,5- and 8-chlorine atoms using Stille reagents results in formation of a completely unsymmetrical trisubstituted BODIPY. Several examples of unsymmetrical BODIPYs were synthesized and characterized using this methodology. Structure features of new BODIPYs are discussed within the context of 14 new X-ray structures, and photophysical parameters of all new BODIPY compounds are reported and discussed.
Electrochimica Acta, 2013
Design, synthesis, optical and electrochemical properties of two novel 4,4-Difluoro-4-bora-3a,4a-diazas-indacene (BODIPY) based donor-acceptor compounds, 1 and 2, are reported in order to elucidate the structure-property relationships in BODIPY based materials. Importantly, these compounds provide opportunity to be used as crosslinkers, since they have three electroactive donor sides. Furthermore, these compounds are polymerized successfully via electrochemical polymerization. The corresponding polymers (P1 and P2) are also characterized by using electrochemical and optical methods in monomerfree electrolyte solutions. It is found that both polymers P1 and P2 exhibit reversible oxidation peaks with half wave potentials of 0.70 V and 0.98 V vs. Ag/AgCl, respectively, and they have low optical band gaps (1.88 eV for P1 and 1.72 eV for P2). It is also noted that the polymers exhibit multielectrochromic properties upon doping: P1 can be switched from pink color in the neutral state to blue color in the oxidized state and P2 can be switched from transmissive pink color when neutralized to transmissive blue color when oxidized.
8-Aryl substituted boron-dipyrromethene dyes: crystal structures and computational studies
Journal of Molecular Structure, 2004
The single crystal X-ray diffraction structures of 8-[4-(acetoxymethyl)]phenyl-2,6-diethyl-4,4-difluoro-1,3,5,7-tetramethyl-3a,4a-diaza-4bora-s-indacene (PAr1Ac, 4) and 8-[4-(3-acetoxypropyl)]phenyl-2,6-diethyl-4,4-difluoro-1,3,5,7-tetramethyl-3a,4a-diaza-4-bora-s-indacene (PAr3Ac, 5) are reported. Although, these two compounds are quite similar, their solid structures are quite unlike, showing remarkable differences in the crystal system, number of molecules in the asymmetric unit, molecular conformation, and supramolecular packing motif. The structures obtained from the X-ray diffraction analysis have been used as starting geometries for quantum chemical calculations (overall energy, HOMO and LUMO, dipole moment, and molecular electrostatic potential). Overall, these results are starting points to understand the photophysical and chemical properties of the so-called 'pyrromethene' dyes. q
Journal of Fluorescence, 2016
In this study, the synthesis of boron dipyrromethene dyes containing mono, bis-2-naphthyloxyhexyloxy and 4-(benzyloxy)phenoxyhexyloxy groups has been reported. Boron dipyrromethene dyes were synthesized from the mono, bis-benzaldehyde derivatives with 2,4-dimethylpyrrole in dichloromethane in the presence of trifluoroacetic, 2,3-dichloro-5,6-dicyano-p-benzoquinon, triethyl amine and boron trifluoride diethyl etherate, respectively. Electrochemical characterization of boron dipyrromethene dyes were c a r r i e d o u t w i t h v o l t a m m e t r i c m e a s u r e m e n t s. Electrochemical studies show that boron dipyrromethene dyes containing mono, bis-2-naphthyloxyhexyloxy and 4-(benzyloxy)phenoxyhexyloxy groups have reversible one reduction potentials unlike irreversible one oxidation potentials.