O objetivo deste trabalho é apresentar a síntese, estrutura cristalina, atividade eletroquímica, propriedades espectroscópicas (IV-TF e UV-Vis) e atividade catalítica frente à oxidação do benzeno do novo complexo mononuclear de cobre(II) [Cu(BTMEA)2Cl]Cl, (1) (BTMEA: bis(2-tienilmetil)-1,2-etilenodiamina). A reação entre BTMEA e [Cu(OH2)2]Cl2, em metanol, resultou em 1, o qual cristaliza como um cristal irregular azul, no grupo espacial Pnna, com a = 20,101(3), b = 12,094(6), c = 12,741(2) Å, V = 3097,4(17) ų, Z = 4. Em 1, o íon cobre está pentacoordenado, mostrando uma geometria de pirâmide de base quadrada distorcida. Complexo 1 apresenta dois processos redox irreverssíveis a - 0,35 V e 0,456 V versus NHE, os quais são atribuídos ao processo redox CuII/CuI e a uma reação acoplada envolvendo o ligante cloreto. A atividade catalítica de 1 foi avaliada através da reação de oxidação do benzeno, usando peróxido de hidrogênio como oxidante. Os produtos da reação (fenol e p-benzoquinona) foram identificados por cromatografia gasosa.

The aim of this work is to present the synthesis, crystal structure, electrochemical behavior, spectroscopic properties (FT-IR and UV-Vis) and catalytic activity toward benzene oxidation of a new mononuclear copper(II) complex [Cu(BMTEA)2Cl]Cl, (1) (BTMEA: bis(2-thienylmethyl)-1,2-ethylenediamine). The reaction between BTMEA and [Cu(OH2)2]Cl2, in methanol, resulted in 1, which crystallizes as an irregular blue crystal, space group Pnna, with a = 20.101(3), b = 12.094(6), c = 12.741(2) Å, V = 3097.4(17) ų, Z = 4. In 1, the copper ion is pentacoordinated, showing a distorted square pyramidal geometry. Complex 1 shows two irreversible redox processes at -0.35 V and at 0.456 V versus NHE, which are associated with the CuII/CuI redox couple and with a coupled reaction involving the chloride ligand. The catalytic activity of 1 was evaluated through benzene oxidation reaction, using hydrogen peroxide as oxidant. Reaction products (phenol and p-benzoquinone) were identified by gas chromatography.

Using the Keldysh nonequilibrium technique, we study current and the tunnelling magnetoresistance (TMR) in a quantum dot coupled to two ferromagnetic leads (FM-dot-FM). The current is calculated for both parallel and antiparallel lead alignments. Coulomb interaction and spin-flip scattering are taken into account within the quantum dot. Interestingly, we find that these interactions play a contrasting role in the TMR: there is a parameter range where spin flip suppresses the TMR, while Coulomb correlations enhance it, due to Coulomb blockade.

We present a normal-mode analysis of coupled photocarrier-phonon dynamics in Te. We consider a dielectric function which accounts for LO phonons and the electron-hole gas within the Debye- Hüuckel model and RPA. Our main finding is the existence of a bare LO phonon mode in the system even at high carrier density. This oscillation is an unscreened L - (q) mode arising from ineffective screening at large wave vectors. This mode is consistent with the bare LO-phonon peak in recent THz-emission spectra of Te.