Rational Design of Star-shaped Molecules with Benzene Core and Naphthalimide Derivatives End Groups as Organic Light-emitting Materials

A series of star-shaped molecules with benzene core and naphthalimides derivatives end groups have been designed to explore their optical,electronic,and charge transport properties as charge transport and/or luminescent materials for organic light-emitting diodes（OLEDs）. The frontier molecular orbitals（FMOs） analysis has turned out that the vertical electronic transitions of absorption and emission are characterized as intramolecular charge transfer（ICT）. The calculated results show that the optical and electronic properties of star-shaped molecules are affected by the substituent groups in N-position of 1,8-naphthalimide ring. Our results suggest that star-shaped molecules with n-butyl（1）,benzene（2）,thiophene（3）,thiophene S？,S？-dioxide（4）,benzo[c][1,2,5]thiadiazole（5）,and 2,7a-dihydrobenzo[d]thiazole（6） fragments are expected to be promising candidates for luminescent and electron transport materials for OLEDs. This study should be helpful in further theoretical investigations on such kind of systems and also to the experimental study for charge transport and/or luminescent materials for OLEDs.

Host–guest materials with room temperature phosphorescence:Tunable emission color and thermal printing patterns

The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their performance is not good enough.In this study,we successfully developed an efficient heatingresponsive room‐temperature phosphorescence material with phosphorescence efficiency and lifetime up to 13.4%and 2.08 s through the simple host–guest doping strategy.Further on,by introducing the additional energy acceptor of fluorescein with concentration‐dependent emission to construct ternary doping systems,the afterglow color was extended from blue to yellow.Accordingly,the multicolor thermal printings have been easily realized,showing the great practical application prospects.

Anthracene Modified by Aldehyde Groups Exhibiting Aggregation-Induced Emission Properties

In order to get an easy way to achieve the transformation from aggregation-caused quenching luminophores （ACQphores） to aggregation-induced emission luminogens （AIEgens）, we took aldehyde groups as the modifying group to decorate anthracene. The fluorescence performances of 9-anthraldehyde （AnA） and 9,10-anthracenedicarboxaldehyde （AnDA） in solution and aggregated state were studied. We found out that the aldehyde group can transform anthracene with aggregation-caused quenching properties to AIEgen. The single-crystal structures analy- sis of AnA and AnDA showed that their structure characteristics are responsible for the AIE properties of AnA and AnDA. On one hand, the aldehyde group can cause steric effects to lower intermolecular n-π packing style in aggregated state. On the other hand, intermolecular H-bonding interactions can restrict the intramolecular rotation and suppress internal charge transfer. These results may supply a new simple method for the transformation from ACQphores to AIEgens on the point of the molecular design.

Synthesis and fluorescent properties of bis-salicyloyl hydrazide metal complexes of some group Ⅳ ions

Four novel organometallic compounds containing tin(Ⅳ),titanium(Ⅳ) and zirco-nium(Ⅳ) ions were synthesized and strong fluorescent emission was observed from two tin(Ⅳ) complexes.