Synthesis, characterization, aggregation-induced emission, solvatochromism and mechanochromism of fluorinated benzothiadiazole bonded to tetraphenylethenes

Abstract

Compounds consisting of unsubstituted, monofluoro and difluoro substituted benzothiadiazole bonded to two tetraphenylethenes were successfully prepared by palladium catalyzed Suzuki-Miyaura cross-coupling reaction of their corresponding co-monomers. All compounds exhibited aggregation-induced emission characteristics when the water fraction was higher than 60% in the THF/water mixtures. The emission maximum for the three compounds was blue-shifted when the water content reached 90% compared to that in THF solution. The intensity of emission maximum of difluorinated benzothiadiazole linked with two tetraphenylethenes was 2.5 times higher in 90% water compared to those in THF solution.Surprisingly, two liquid crystal phases with two distinct emission colors were observed only for the compound containing difluorinated benzothiadiazole bonded to two tetraphenylethene. All compounds showed remarkable solvatochromic properties in selected solvents with different polarities. The powder XRD results and mechanochromism of the compounds suggested that the solid state structures can change from one form to another by grinding, fuming or annealing processes.

Identification of the Irreversible Redox Behavior of Highly Fluorescent Benzothiadiazoles

“…As the mechanochromic nature of BTDs was shown before, all samples were ground before the spectroscopic measurements. [37] The solid state fluorescence spectra of our BDT dyes (Figure 4 and Figure S14/S15) closely match with the respective fluorescence spectra in DCM. The Φ fl SS are between 33 % (1) and 72 % (3) and are thus lower compared to the values determined in n- [38].…”

Aggregation‐induced multicolor luminescent nanoparticles with adaptive and fixed cores derived from brominated tetraphenylethene‐containing block copolymer

“…This occurs because of the incorporation of the BTz acceptor to form a TPE‐BTz‐TPE sequence in the core with a slight increase in the conjugated length and electron‐withdrawing effect compared to those of the TPE unit. BTz has been frequently employed as an electron acceptor owing to its relatively high‐electron affinity and π‐extended planar structure for donor–acceptor chromophores containing TPE 52,53 . The NP(TPE‐BTz) showed relatively high fluorescence quantum yield in THF solution (4.2%) and in film state (11%), as shown in Table 1.…”

“…BTz has been frequently employed as an electron acceptor owing to its relatively high-electron affinity and π-extended planar structure for donor-acceptor chromophores containing TPE. 52,53 The NP(TPE-BTz) showed relatively high fluorescence quantum yield in THF solution (4.2%) and in film state (11%), as shown in Table 1. In contrast, the blue emission color was detected for NP(TPE-An) with the emission peak appearing at 440 nm, exhibiting approximately 60 nm blue shift compared to NP(TPE-Th) (Figure S10c and S11c, SI).…”

Synthesis of Cyano-Substituted Conjugated Polymers for Photovoltaic Applications

“…3-(2-octyldodecyl) thiophene (1), 4.7-dibromo-5-fluorobenzo[c] [1,2,5] thiadiazole (3), and 2,6-bis(trimethyltin)-4,8-bis(5-2-ethylhextyl)thiophene-2-yl)benzo[1.2-b:4,5-b’]dithiophene (9) were synthesized according to the procedure described in previous literature [33,34,35]. (6,6)-Phenyl C 71 butyric acid methyl ester (PC 71 BM) and (6,6)-Phenyl C 61 butyric acid methyl ester (PC 61 BM) were purchased from Nano-C, Inc.(Westwood, USA) All other chemicals and solvents were obtained from Aldrich.…”