Series Of Star-shaped Molecules Research Articles

Intramolecular Energy Transfer in a Series of Star-Shaped Molecules with a Central Porphyrin Core and Four Oligocarbazole Arms

A series of star-shaped molecules T(OCAn)Ps (n = 2–6) based on porphyrin as a core and oligocarbazole as monodisperse arms has been investigated by steady-state spectroscopy, femtosecond transient ...

Rational Design of Star-Shaped Molecules with Benzene Core and Naphthalimides 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.

New Usage for Cyclotrimerization Reaction: A Facile Synthesis of 1,3,5-Triazine Derivatives

Series of star-shaped molecules based on 1,3,5-triazine core have been synthesized via CF3SO3H-mediated cyclotrimerization reaction, and then characterized by 1H-NMR, 13C-NMR, MALDI-TOF-MS, and elemental analysis. The effects of different factors, such as the steric hindrance and electronegativity on the reaction efficiency, are systematically studied. The results indicate that the steric hindrance plays an important role in the reaction, while electronegativity has little impact on this reaction. In addition, the bridges including ethylene group and carbon atom between 1,3,5-triazine core and peripherals are firstly studied in this work, which expands the application of CF3SO3H-mediated cyclotrimerization reaction. Moreover, we have successfully broadened the cyclotrimerization reaction to the preparation of 1,3,5-triazine derivatives with different substituents as the peripheral, which is promising for preparation of single-layer multi-functional optoelectronic materials.

Structural relationship between photophysical data of 1,3,5-trisubstituted oligoaryleneethynylene benzene star-shaped molecules and number of carbon atoms

A series of star-shaped molecules have been prepared by different methods. These molecules present an important electronic delocalisation between the attractive central ring, i.e. benzene and the three ends π-electron donor groups. These interesting molecules are currently considered because of their wide potential applications. Some of them can act as discotic liquid crystals (DLCs). The 1,3,5-benzene core acts as an effective π-electron center to conjugate with the oligoaryleneethynylene groups of the 1,3,5-trisubstituted oligoaryleneethynylene benzene star-shaped molecules. Graph theory is an exploration of techniques in discrete mathematics and its results can be applied in various fields of science. Several concepts of graph theory have been found to be useful tools in both QSAR and QSPR. This theory provides many different methods of characterising chemical structures numerically. In this study, we utilised the number of carbon atoms as a useful structural character (Cn ) for relating structure to photophysical properties of the star-shaped molecules 1–19. The interesting results obtained here present the good correlation between the index of Cn , the number of carbon atoms in each of the star-shaped molecular structures that are indicated here, with their photophysical properties. Some of the photophysical data that were communicated in the literature are: quantum yield (Φ f ), fluorescence emission maximum FEM (λ em) and absorbance maximum wavelength AMWL (λ abs). The interesting results of the relationship between ‘Cn ’ and the photophysical data of these star-shaped molecules are presented.

Novel starshaped molecules based on fluorene

A series of starshaped molecules with different cores such as benzene, triphenylbenzene and triphenylamine and fluorene-moieties as side arms were synthesized by suzuki cross-coupling. These low molecular weight compounds form stable glasses and are easily obtained in high purity by column chromatography and sublimation. Variation of the alkyl chain length in the 9 position of the fluorenes and changing the core have a great influence to their glassforming abilities and the glass transition temperature, which range from 57 °C to 118 °C. All starshaped molecules show blue emission, which can be fine-tuned by the choice of the cores. A first two-layer device with the configuration ITO/NPB/TFPB-Bu/Ca was prepared by vacuum evaporation and shows an external quantum efficiency of 1.2 % at 10 V.