4,6-Bis((E)-2-(4′-N,N-diphenylamino-[1,1′-biphenyl]-4-yl)vinyl)-2-phenylpyrimidine

In this contribution, we designed a 4,6-distyrylpyrimidine chromophore with diphenylamino electron-donating groups and biphenylenevinylene extended π-conjugated linkers. This compound has been synthesized in two steps from 4,6-dimethyl-2-phenylpyrimidine by a double Knoevenagel reaction with 4-bromobenzaldehyde followed by a double Suzuki–Miyaura cross coupling reaction with 4-(N,N-diphenylamino)phenylboronic acid. This compound exhibits intense emission in moderately polar solvents as well as in solid state. This compound is characterized by an intense emission solvatochromism with emission ranging from blue in non polar n-heptane to orange in dichloromethane. This chromophore is also sensible to the presence of acid with a bathochromic shift of the charge transfer absorption band and emission quenching.

Solvent-Driven Chirality Switching of a Pillar[4]arene[1]quinone Having a Chiral Amine-Substituted Quinone Subunit

Several new chiral pillar[4]arene[1]quinone derivatives were synthesized by reacting pillar[4]arene[1]quinone (EtP4Q1), containing four 1,4-diethoxybenzene units and one benzoquinone unit, with various chiral amines via Michael addition. Due to the direct introduction of chiral substituents on the rim of pillar[n]arene and the close location of the chiral center to the rim of EtP4Q1, the newly prepared compounds showed unique chiroptical properties without complicated chiral resolution processes, and unprecedented high anisotropy factor of up to −0.018 at the charge transfer absorption band was observed. Intriguingly, the benzene sidearm attached pillar[4]arene[1]quinone derivative 1a showed solvent- and complexation-driven chirality inversion. This work provides a promising potential for absolute asymmetric synthesis of pillararene-based derivatives.

Optically probing the localized to delocalized transition in Mo2–Mo2 mixed-valence systems

A transition of mixed-valence systems from Class II to Class III crossing the Class II–III borderline is achieved by four thienylene-bridged Mo2 dimers, and is probed using spectral parameters of intervalence charge transfer absorption (band energy, intensity and shape). This study offers fresh and detailed observations of optical behaviors of MV compounds in different regimes.

The Photoluminescence Behaviors of a Novel Reddish Orange Emitting Phosphor CaIn2O4:Sm3+Codoped with Zn2+or Al3+Ions

A novel reddish orange phosphor CaIn2O4:Sm3+codoped with Zn2+or Al3+ions was prepared by solid state reaction and their luminescence properties were investigated under near ultraviolet excitation. The strategy of Zn2+or Al3+ions codoping was used with the aim to improve the luminescence properties of CaIn2O4:Sm3+, but the concrete effects of the two ions is different. The introduction of Zn2+ions can produceZnIn'defects that favor charge balance in CaIn2O4:Sm3+to facilitate its photoluminescence. The effect of Al3+ions codoping can effectively transfer energy from charge-transfer absorption band to characteristic transition of Sm3+ions, utilizing more energy from host absorption for the photoluminescence of Sm3+ions. Based on these mechanisms, the luminescence intensity of CaIn2O4:0.6%Sm3+was enhanced to 1.59 times and 1.51 times when codoping amount of Zn2+and Al3+ions reached 0.6%. However, the chromaticity coordinates of CaIn2O4:0.6%Sm3+almost did not have any changes after Zn2+ions or Al3+ions codoping; those are still located at reddish orange region. The excellent luminescence properties of CaIn2O4:0.6%Sm3+,0.6%Zn2+and CaIn2O4:0.6%Sm3+,0.6%Al3+demonstrate that they both have potential application value as new-style reddish orange phosphors on light-emitting diode.

3-Methylpiperidinyl Carbodithioates as Building Blocks for 1,3-Dithiolium Derivatives

New 1,3-dithiolium derivatives have been synthesized by heterocyclocondensation of various 3-methylpiperidinyl carbodithioates derived from 2-hydroxypropiophenones. Thus, 1,3-dithiolium perchlorates have been obtained by the treatment of the corresponding dithiocarbamates with a mixture of acetic and sulfuric acid, followed by the addition of perchloric acid. 1,3-Dithiolium perchlorates have been converted to the corresponding 2-(1,3-dithiolium) phenolates under weak basic conditions. These phenolates exhibit mesoionic character with an internal charge transfer absorption band.

Pyridinium N-phenolate betaine dyes as empirical indicators of solvent polarity: Some new findings

Solutions of the zwitterionic betaine dye 4-(2,4,6-triphenylpyridinium-1-yl)-2,6-di- phenylphenolate are solvatochromic, thermochromic, piezochromic, and halochromic. That means the position of its longest-wavelength intramolecular charge-transfer absorption band depends on solvent polarity, solution temperature, external pressure, and the nature and concentration of added salts. The extraordinarily large negative solvatochromism of this standard betaine dye has been used to establish UV/vis spectroscopically an empirical scale of solvent polarity, called ET(30), respectively ETN scale, meanwhile known for many organic solvents and solvent mixtures. In this review, the solvatochromic properties of some new hydrophilic and lipophilic betaine dyes with better solubility in water (respectively, nonpolar solvents), as well as some recent applications of these betaine dyes in various fields of interest [e.g., microheterogeneous (micellar) and polymer solutions, chemical sensors, as well as surface polarity of silicas, aluminas, and cellulose derivatives] are described.