995 resultados para Complex Intervals
Resumo:
The photophysical properties of the complex Sm(PM)(3)(TP)(2) [PM = 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone, TP = triphenyl phosphine oxide] are determined in crystal state, and energy transfer process is modeled for ligands to center Sm(III) ion. The characteristic luminescence of Sm(III) is sensitized by PM and TP, and most of transitions from excited state (4)G(5/2) of Sm3+ are detected.
Resumo:
The tertiary lanthanide complexes [Ln(hfth)(3)phen] (Ln=Er, Nd, Yb, Sm) and [Pr(tfnb)(3)phen] have been Successfully covalently attached in the ordered SBA-15 mesoporous materials via a functionalized 1,10-phenanthroline group 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline (Phen-Si). The derivative materials [denoted as Ln(hfth)(3)phen-S15 and Pr(tfnb)(3)phen-S15; Ln=Er, Yb, Nd, Sm; hfth=4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dionate; tfnb=4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedionate] were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N-2 adsorption/desorption.
Resumo:
We describe a facile one-pot process to synthesize Ag nanoplates by reducing silver nitrate with 3,3',5,5'-tetramethylbenzidine (TMB) at room temperature. The silver nanoplates were highly oriented single crystals with (111) planes as the basal planes. TMB can be readily oxidized to charge-transfer (CT) complex between TMB, as a donor, and (TMB)(2+), as an acceptor. The pi-pi interaction of the neutral amine (TMB) and diiminium structure (dication, TMB2+) result in the formation of one-dimensional CT complex nanofiber.
Resumo:
The crystal structure of Er(PM)(3)(TP)(2) [PM = 1-Phenyl-3-methyl-4-isobutyryl-5-pyrazoloiie, TP = triphenyl phosphine oxide] was reported and its photoluminescence properties were studied by UV-vis absorption, excited, and emission spectra. The Judd-ofelt theory was introduced to calculate the radiative transition rate and the radiative decay time of 3.65 ms for the I-4(13/2) -> I-4(15/2) transition of Er3+ ion in this complex.
Resumo:
A novel catalyst system based on nickel(II) tetraphenylporphyrin (Ni(II)TPP) and methylaluminoxane for styrene polymerization was developed. This catalyst system has a high thermal stability and show fairly good activity. The obtained polystyrene (PS) was isotactic-rich atactic polymer by C-13 NMR analysis, and its molecular weight distribution was rather narrow (M-w/M-n approximate to 1.6, by GPC analysis). ESR revealed that Ni(II)TPP pi cation radicals were formed in the polymerization and could remain in the resulting PS stably. The mechanism of the polymerization was discussed and a special coordination mechanism was proposed. The PS product containing Ni(II)TPP pi cation radicals can be used as a potential functional material.