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The synthesis, luminescence properties, experimental determination and theoretical calculation of the emission quantum yield of Eu(NTA)3.2L complexes, where NTA is naphtoiltri-fluroacetone and L denotes H2O or DMSO (dimethyl sulphoxide), were reported. The compounds were characterized by elemental analysis (carbon, hydrogen and europium), thermal analysis, UV-visible absorption and photoluminescence spectroscopies. The experimental quantum yields were determined based on a method previously proposed by Bril and collaborators. The Eu(NTA)3.2DMSO compound shows a high value for the Ω2 intensity parameter (35.8 × 10−20 cm2), reflecting the hypersensitive nature of the 5D0 → 7F2 transition and indicating that the lanthanide ion is in a highly polarizable chemical environment. The experimental quantum yield measured for that compound, 0.75, is one of the highest so far reported for solid-state europium complexes. The theoretical calculations of the quantum yield were carried out by solving an appropriate set o...

In this paper we report on a photoluminescent investigation of complexes involving Sm 3+ -β-diketonates with sulfoxides, phosphine oxides and amides ligands. In the synthesis of the coordination compounds we used samarium tris(thenoyltrifluoroacetonate) dihydrated precursor with the following ligands (L): DBSO and PTSO sulfoxides; TPPO phosphine oxide and (PHA) N -phenylacetamide. They have shown high orange luminescence characteristic of the Sm 3+ ion. The emission spectra of the Sm 3+ -complexes present narrow bands arising from the 4 G 5/2 → 6 H J ( J =5/2, 7/2, 9/2, 11/2) transitions with the hypersensitive 4 G 5/2 → 6 H 9/2 transition as a prominent group. It is observed an efficient intramolecular energy transfer from the triplet state (T) of the ligands to the emitting 4 G 5/2 state of the Sm 3+ ion. The experimental intensity parameters ( η Sm and η Eu ) for the Sm and Eu complexes have been determined and compared. The lifetimes ( τ ) of the emitting level 4 G 5/2 of the Sm-complexes are approximately 10 times higher than in the precursor compound [Sm(TTA) 3 ·(H 2 O) 2 ] indicating that radiative processes are operative in all the compounds due to the absence of multiphonon relaxation by coupling with the OH oscillators.

Photoluminescent properties of the tris(thenoyltrifluoroacetonate)europium(III) dihydrate with dimethyl sulfoxide (DMSO), in the solid state, are reported. The compound Eu(TTA)3·2DMSO and the precursor salt were characterized by IR spectroscopy, differential scanning calorimetry and elemental analysis. The emission data indicate that the substitution of the two water molecules by DMSO ligand in the complex causes an intensification of luminescence corresponding to the 5D0→7FJ (J=0–4) transitions associated with one of the site symmetries. Large values of the Ω 2 intensity parameter (35.2×10−20 cm2) were obtained, reflecting the hypersensitive character of the 5D0→7F2 transition and indicating that Eu3+ ion is in a highly polarizable chemical environment. This is consistent with systems containing sulfoxide ligands DBSO and PTSO. The DMSO complex also shows a higher value for the Ω 4 parameter (6.8×10−20 cm2) as a consequence of the difference in the basicity of the oxygen donor ligand. Lifetime measurements (τ=0.72 ms) confirm that the Eu3+ luminescence has a higher efficiency than in the case of the hydrated compound.

We report the experimental determination and theoretical calculation of the 4f–4f emission quantum yield (q) and 5D0 excited state lifetime in the Eu (TTA)3.nL compounds (where TTA=thenoyltrifluoroacetonate, L denotes 1,10-phenantroline orp-tolyl sulfoxide and n=1 or 2). The experimental q values for these compounds vary significantly by changing the L ligand. The relation between the emission quantum yield and photophysical characteristics of the compounds is discussed. The calculations are carried out by using theoretical models for ligand–rare earth ion energy transfer processes and numerical solutions of the rate equations. Pathways for the intramolecular energy transfer process between the ligands and the rare earth ion are proposed. The theoretical results agree well with the experimental data for the compounds analyzed.

Photoluminescent properties of the inclusion compound of β-cyclodextrin and tris(dibenzoylmethane)europium(III) dihydrate, in the solid state, are reported. This compound and the precursor salt, Eu(DBM)3 · 2H2O (DBM=dibenzoylmethane), were characterized by IR spectroscopy, X-ray powder diffraction and differential scanning calorimetry. The emission data indicate that the host-guest interaction (at 77 K) causes an intensification of some bands corresponding to the 5D0→7FJ (J=0–4) transitions associated with one of the site symmetries existing in the guest compound. Based on the luminescence spectrum of the supramolecular compound the Ω λ experimental intensity parameters (λ=2 and 4) were calculated for the electronic transitions 5D0→7F2, 4. The value of the Ω 2 intensity parameter for this new compound is smaller than for the guest, suggesting an effective interaction between the β-cyclodextrin and the closer chemical environment of the Eu3+ ion. On the other hand, the values of the Ω 4 parameter for the inclusion compound are twice larger than the one of the guest, suggesting that the steric effect is more significant in the supramolecular species. Comparison between the luminescence lifetimes of the guest and inclusion compound indicates that the β-cyclodextrin contributes to increase the lifetime of the 5D0 emitting level. The time-resolved spectra of the inclusion compound corroborate the presence of more than one site symmetry occupied by the rare earth ion.

We discuss the syntheses, properties and the luminescence of the complexes, Eu(TTA) 3 · 2L · H 2 O, where TTA = thenoyltrifluoroacetonate, L=15C5 (1,4,7,10-tetraoxa-13-azacyclopentadecane,13-phenyl) and 18C6 (2,3,11,12-dicyclohexano-1,4,7,10,13,16-hexaoxacyclooctadecane). The film complexes with 15C5 and 18C6 ligands contain only one water molecule. The Ω λ experimental intensity parameters ( λ =2 and 4) and the ratio between the intensities of the 5 D 0 → 7 F 0 and 5 D 0 → 7 F 2 transitions ( R 02 ) were obtained for the compounds Eu(TTA) 3 · 2(15C5) · H 2 O ( Ω 2 =39.5 × 10 −20 cm 2 , Ω 4 =8.9 × 10 −20 cm 2 and R 02 =0.0087) and Eu(TTA) 3 · 2(18C6) · H 2 O ( Ω 2 =39.3 × 10 −20 cm 2 , Ω 4 =5.8 × 10 −20 cm 2 and R 02 =0.0098). The macrocyclic compounds, powder form, were also measured. The luminescence spectra of the Eu(TTA) 3 · 2L · H 2 O films give the largest Ω 2 intensity parameter, due to the hypersensitive 5 D 0 → 7 F 2 transition and indicating that the rare earth ion is in a polarizable chemical environment. The lifetimes of the macrocyclics complexes in the powder and film were measured.

Various divalent rhodium complexes Rh2(L)4 (L = acetate, propionate, butyrate, trifluoroacetate and trifluoroacetamidate) have been found to bind to non-defatted human serum albumin (HSA) at molar ratios about 8:1. The circular dichroism measurements showed that the more liposoluble carboxylates, butyrate and trifluoroacetate, caused the major alterations of the secondary structure of HSA. Stern-Volmer constants for the fluorescence quenching of the buried Trp214 residue by these complexes were also higher for the lipophilic metal compounds. In the case of the rhodium carboxylates it was observed that their denaturating and quenching properties could be explained in terms of their liposolubilities: the higher their lipophilic characters, the higher their abilities to penetrate inside the protein framework leading to structural alterations, and the closer they could get to the Trp residue causing fluorescence quenching. The liposoluble amidate complex, Rh2 (tfc)4, presented an intermediate quenching and did not cause structural alterations in the protein, presumably not penetrating inside the peptidic backbone. This study shows that it is possible to design new antitumor metal complexes which bind, to a large extent, to a transport protein causing little structural damage.

In this work we present a study of the luminescence intensity of Eu(TTA)3·xL, where TTA=thenoyltrifluoroacetonate (L denotes DBSO and PTSO sulfoxides, and derivatives of 15C5 and 18C6 macrocyclics). The complexes with 15-crown-5 ether ligand contain two H2O molecules. The complexes were characterized by a microanalytical procedure, IR spectroscopy and molar conductance. They show high luminescence mainly in the red region. The characteristic emission spectra of Eu3+ in these compounds show uncommonly high values of the Ω2 intensity parameters, reflecting the hypersensitive behavior of the 5D0→7F2 transition and indicating that the rare earth ion is in a highly polarizable chemical environment. The 5D0→7F0 transition splitting, in the case of Eu(TTA)3·18C6, indicates more than one site of symmetry occupied by Eu3+.

We report the experimental determination and a theoretical calculation of the 4f–4f emission quantum yield in the Eu(thenoyltrifluoroacetonate)3.2(dibenzyl sulfoxide) compound. The experimental procedure for determining the quantum yields is based on a method previously proposed by Bril and coworkers. The theoretical calculations are carried out by solving an appropriate set of rate equations and by using spectroscopic parameters and energy transfer rates recently reported for this compound. For the sake of comparison, the hydrated compound (two water molecules in the place of the dibenzyl sulfoxide) is also studied. Good agreement between theory and experiment is obtained, provided that the lifetime of the lowest triplet level of the donor ligand is ≥10−5 s at room temperature.

Luminescent biocellulose membranes were obtained by incorporation of ethanolic solutions of the europium compounds [Eu(BTFAC)3(H2O)2], [Eu(BTFA)3(DBSO)2], [Eu(BTFA)3(PTSO)2] and [Eu(BTFA)3(FSO)2] (BTFAC- 4,4,4-Trifluoro-1- phenyl-1,3-butanedione DBSO- dibenzyl sulfoxide, PTSO- p-Tolyl sulfoxide and FSO- phenyl sulfoxide). Selfsustainable semi-transparent composite membranes were obtained showing strong emission under UV exctiation. The antenna hole played by the ligands was observed to be more efficient in the composite membranes than in the precursor complexes which by themselves are also strong red emitter compounds. These new multifuctional membranes could find application in different areas as phosphors and UV→Visible energy converting devices.

O presente estudo objetivou determinar a capacidade de ampliação das granjas de produção de frangos de corte do município de Rio Verde, GO, Brasil, baseado na capacidade de utilização da cama de frango como fonte de adubação na própria propriedade. Através de questionários, foram coletadas informações sobre a quantidade de aves alojadas e do tamanho das propriedades. Para determinar a capacidade de utilização da cama de frango, foram considerados 3 níveis tecnológicos (baixo, médio e alto). Considerando a simulação para baixo nível tecnológico (utilização de 1,8 toneladas de cama de frango/ha/ano) não foram verificadas possibilidades de ampliação do número de galpões em nenhuma das granjas pesquisadas, existindo ainda a produção de cama referente a 244 galpões acima da capacidade de utilização. Para o nível médio de tecnologia (4,4 toneladas de cama de frango/ha/ano) observou-se que poderiam ser ampliados 24 galpões em terras próprias, de algumas propriedades. Entretanto, ocorreu um excedente equivalente à produção de cama de 161 galpões, por último, nas propriedades de alto nível tecnológico (8,7 toneladas de cama de frango/ha/ano), poderiam ser ampliados 135 galpões em algumas propriedades e em outras ocorreria um excedente equivalente à produção de 96 galpões.

A utilização de métodos culturais no manejo de plantas daninhas é sempre importante dentro de sistemas agrícolas conservacionistas e que visam uma menor quantidade de herbicidas no ambiente. A escolha de cultivares mais competitivos com as espécies infestantes é mais uma ferramenta dentro do manejo integrado de plantas daninhas em lavouras de soja, bem como em outras culturas. Com o objetivo de avaliar o potencial competitivo de cultivares de soja difundidos no sudoeste de Goiás, em relação às plantas daninhas, visando recomendá-los para cultivo em áreas com histórico de alta densidade de espécies infestantes, foram conduzidos dois experimentos a campo em Rio Verde, GO, sendo avaliados quatro cultivares de soja de ciclo precoce no experimento 1: Monsoy 6101, Monsoy 8001, Emgopa 316 e Coodetec 204; e quatro de ciclo médio no experimento 2: Conquista, Codetec 211, Emgopa 315 e Vencedora. Também foram avaliados dois tipos de manejo de plantas daninhas: área capinada manualmente (sem plantas daninhas) e área não-capinada (com infestação de plantas daninhas). Aos 16, 25 e 46 dias após a semeadura (DAS), avaliaram-se a altura média e a biomassa seca de plantas; aos 63 DAS, a porcentagem de cobertura do solo pelos cultivares de soja; e, ao final do ciclo, o rendimento de grãos. Todos os cultivares de soja, de ciclo precoce ou médio, exibiram queda no rendimento de grãos com o nãocontrole das plantas daninhas. Emgopa 316 e Coodetec 204 mostraram ser mais competitivos, entre os de ciclo precoce, no controle de plantas daninhas. O mesmo aconteceu com o cultivar Emgopa 315, entre os de ciclo médio. Estes últimos são os mais indicados para serem cultivados em áreas com maior incidência de plantas daninhas. The use of cultural methods in conservationist agricultural system is important for weed management, since it decreases the amount of the chemical products applied. The use of more competitive cultivars seems to be one of the most important weed management methods, which valid for soybean as well as other crops. Two field experiments were carried out to evaluate the competitive potential of soybean varieties, among those officially recommended for southwestern Goiás, against weeds in Rio Verde,GO aiming to propose the cultivation of better-quality varieties in areas with high weed pressure. Four short-season soybean varieties were evaluated in experiment 1: (Monsoy 6101, Monsoy 8001, Emgopa 316 and Coodetec 204) and four medium-season soybean varieties in experiment 2 (Conquista, Coodetec 211, Emgopa 315 and Vencedora). All the cultivars were evaluated under both weed management systems, i.e., manual weed control (absence of weeds) and no weed control (presence of weeds). At the 16th, 25th and 46th days after sowing (DAS), both plant height and plant dry matter were evaluated; at the 63rd DAS, the percentage of soil covered by the soybean cultivars was evaluated and at the end of the plant season, yield was evaluated. All the cultivars displayed yield reduction in the system with no weed control. However, Emgopa 316 and Coodetec 204 were found to be the most competitive among the short-season cultivars. Among the medium-season cultivars, Emgopa 315 showed the same tendency. Therefore, these two varieties are the most recommended to be cultivated in areas with high weed pressure.