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A series of novel V‐shaped luminophores containing electron‐withdrawing dibenzo[f,h]quinoxaline core and arylthienyl donor fragments at positions 2 and 3 has been synthesized. The absorption spectra (UV/vis) were recorded in several solvents, whereas emission spectra were recorded in solutions and powders. The solvatochromism as well as halochromism of obtained compounds was also explored. Electronic‐structure calculations using quantum‐chemistry methods were performed to further analyse experimental results. All characteristics were compared with that of 2,3‐bis(arylthienyl)quinoxaline counterparts. The halochromic effect studies showed that upon gradual addition of trifluoroacetic acid (TFA) to the toluene solution of diethylaminophenyl‐substituted dibenzo[f,h]quinoxaline chromophore, absorption and emission changed. Observed band shifts were more distinct in the case of mentioned quinoxaline than for other derivatives. All of the (dibenzo[f,h])quinoxaline chromophores exhibited good sensitivity toward nitro‐containing explosives with high Stern‐Volmer constants up to 57800 M−1, these results are remarkable for such heterocyclic systems. [ABSTRACT FROM AUTHOR]

The novel terbium(III) tetrakis(β‐diketonates) M[TbL4] with different alkali metal counterions (Na, K, Cs) based on functionalized trifluoromethylated β‐diketonate are reported. An efficient approach to alkali metal β‐diketonates ML (M = Na, K, Cs) is proposed, which does not require the alkaline media promoting the destruction of 1,3‐dicarbonyl compounds. The transformation of lithium β‐diketonate LiL into the corresponding alkali metal β‐diketonate ML has been achieved under mild conditions using alkali metal fluorides. Organic ligand generates the multiplicity of coordination modes through a diketonate fragment, methoxy group and trifluoromethyl substituent. The alkali metal ion changes the geometry of coordination environment of the terbium(III) ion and affects the crystal packing of complexes. The additional coordination centers in the ligand coupled with a small atomic radius of sodium ion resulted in a construction of a rare example of discrete lanthanide tetrakis(β‐diketonate) Na[TbL4]. Moreover, this complex exhibited bright luminescence and mechanoluminescence in contrast to polymeric TbIII tetrakis(β‐diketonates) with K and Cs. [ABSTRACT FROM AUTHOR]

Abstract: A series of V‐shaped luminophores containing electron‐withdrawing quinoxaline core and arylthienyl donor fragments at positions 2 and 3 has been successfully synthesized. Their photophysical properties in two solvents as well as halochromism have been studied, and the ability of 4‐diethylaminophenyl derivative to function as colorimetric and luminescent pH sensor has been demonstrated with significant color changes and luminescence switching upon the introduction of acid. [ABSTRACT FROM AUTHOR]

A convenient synthetic route to novel thienoacene systems bearing a fused pyrimidine ring has been advanced. The commercially available 5-bromopyrimidine was used as the starting material to obtain various dithienoquinazoline systems through nucleophilic aromatic substitution of hydrogen (the SNH reaction), Suzuki cross-coupling, and oxidative photocyclization. The redox and optical properties of some of the new compounds have been investigated. The data obtained show the potential of dithienoquinazoline systems in organic electronic applications. [ABSTRACT FROM AUTHOR]

B The Front Cover b shows the mechanoluminescence (ML) of heterobimetallic terbium-sodium -diketonate illustrated as a snowboarder going down a snow slope. B The Front Cover b shows the mechanoluminescence (ML) of heterobimetallic terbium-sodium -diketonate illustrated as a snowboarder going down a snow slope. Only when passing through the Na area does the snowboarder make a green sparkling snow spray, which symbolizes the ML of the Tb-Na complex. [Extracted from the article]