Eduardo Rezende Triboni

Efficient Sonochemical Synthesis of 3‐ and 4‐Electron Withdrawing Ring Substituted N‐Alkyl‐1,8‐naphthalimides from the Related Anhydrides

Abstract 1,8‐N‐alkyl‐naphthalimides substituted with electron withdrawing groups were readily prepared in high yields using ultrasound in aqueous media.

Violet ZnSe/ZnS as an alternative to green CdSe/ZnS in nanocrystal-fluorescent protein FRET systems.

Fluorescent proteins from the green fluorescent protein family strongly interact with CdSe/ZnS and ZnSe/ZnS nanocrystals at neutral pH. Green emitting CdSe/ZnS nanocrystals and red emitting fluorescent protein dTomato constitute a 72% efficiency FRET system with the largest alteration of the overall photoluminescence profile, following complex formation, observed so far. The substitution of ZnSe/ZnS for CdSe/ZnS nanocrystals as energy donors enabled the use of a green fluorescent protein, GFP5, as energy acceptor. Violet emitting ZnSe/ZnS nanocrystals and green GFP5 constitute a system with 43% FRET efficiency and an unusually strong sensitized emission. ZnSe/ZnS-GFP5 provides a cadmium-free, high-contrast FRET system that covers only the high-energy part of the visible spectrum, leaving room for simultaneous use of the yellow and red color channels. Anisotropic fluorescence measurements confirmed the depolarization of GFP5 sensitized emission.

Synthesis of 4-alkoxy-N-substituted-1,8-naphthalimides

The present work deals with two improved methods for the synthesis of 4-alkoxy-N-alkyl-1,8-naphthalimides from 4-nitro-N-alkyl-1,8-naphthalimides employing in situ generation of the alkoxylating agent in the alcoholic saturated solution of alkaline metal carbonates.

Naphthalimide-derivative with blue electroluminescence for OLED applications

Abstract The synthesis and characterization of the 4-(2-fenoxi-p-xileno)-N-methyl-1,8-naphthalimide, referred to here as NPOX, is described in this work. The characterization of NPOX was performed using proton nuclear magnetic resonance spectroscopy (1H NMR), UV–visible and fluorescence emission spectroscopy. The LUMO and HOMO levels of NPOX were estimated using the electrochemical method, respectively, at 3.4 eV and 6.1 eV with an energy gap of 2.7 eV. The NPOX is soluble in chloroform such that when it evaporates, it becomes a transparent film with fluorescence emissions occurring at 456 nm when excited at 363 nm. Using the Space-Charge-Limited-Current (SCLC) model, we obtained the value of the mobility of the positive charge carriers to be μ ≅ 5 × 10−5 cm2 V−1 s−1. These properties raise the possibility of using the NPOX as the emitting layer in an organic light-emitting diode (OLED) with emission in the blue region, as demonstrated by the fabrication of an OLED with an ITO/PEDOT:PSS/NPOX/Al structure and light emission peaking at approximately 465 nm.

Synthesis and Properties of New Paramagnetic Hybrid Bayerite from Al(0)/Naphthalene Dianhydride Reaction

The reaction of Naphthalene 1,4,5,8-dianhydride (NTCDA) with elemental aluminum(0) powder is studied in an aqueous alcoholic KOH mixture to search for the NTCDA anion and dianion electron-adducts. After analyzing various reaction conditions it was found that the reaction yielded a greenish precipitate in 3:1 (v:v) ethanol:water mixture. This powder is composed mainly of aluminum trihydroxide crystallites of bayerite [α-Al(OH3)(s)] and the organic content is approximately 6%. This hybrid material proved to be paramagnetic even after exposure to air for one year and at temperatures up to 200 oC. Typical carbonylic bound to metal IR bands and reflectance UV-VIS spectra demonstrate the entrapment of NTCDA radical anion into the aluminum trihydroxide, hence rendering its green color and a paramagnetic behavior. Thus, besides the understanding of an aluminum reaction in suspension, the entrapment of an organic material (NTCDA) that stays stable as the corresponding radical can provide an interesting option for the synthesis of aluminum trihydroxide composites.