| 1. |
- Sábio, Rafael M., et al.
(author)
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Near-Infrared Luminescence from Visible-Light-Sensitized Ruthenium(II)-Neodymium(III) Heterobimetallic Bridged Complexes Containing Alkoxy(silyl) Functional Groups
- 2020
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In: Journal of the Brazilian Chemical Society. - : Sociedade Brasileira de Quimica (SBQ). - 0103-5053 .- 1678-4790. ; 31:4, s. 694-702
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Journal article (peer-reviewed)abstract
- New infrared emitting d-f (ruthenium(II)–neodymium(III)) heterobimetallic complexes with alkoxy(silyl) functional groups have been prepared. Visible excitation evidenced energy transfer processes from the ruthenium(II) donor to neodymium(III) acceptors leading to infrared emission. Energy transfer rates (kEnT) and efficiency of energy transfer (ηEnT) are, respectively, 0.61 × 107 s-1 and 44% for RuL1–NdL3 complex. Larger values of kEnT (3.04 × 107 s-1) and ηEnT (84%) were detected for RuL2–NdL4 complex. RuL1–NdL3 and RuL2–NdL4 complexes were fully characterized by elementary analysis (EA), mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR) and Fourier transform Raman spectroscopy (FT-Raman). Total correlation spectroscopy (TOCSY1D), 1H{13C} heteronuclear single quantum correlation (HSQC) and 1H{13C} heteronuclear multiple bond correlation (HMBC) nuclear magnetic resonance (NMR) analyses were also carried out to characterize NdL3 and RuL1–NdL3 complexes. The presence of trialkoxysilyl-substituted ligands would allow further grafting onto any silica or silicated surface aiming at applications as new luminescent near infrared (NIR)-emitting biosensors or biomarkers.
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| 2. |
- Kihlman, Martin, et al.
(author)
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Cellulose Dissolution in an Alkali Based Solvent : Influence of Additives and Pretreatments
- 2013
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In: Journal of the Brazilian Chemical Society. - : SOC BRASILEIRA QUIMICA, Brazil. - 0103-5053 .- 1678-4790. ; 24:2, s. 295-303
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Journal article (peer-reviewed)abstract
- The distinction between thermodynamic and kinetics in cellulose dissolution is seldom considered in the literature. Therefore, herein an attempt to discuss this topic and illustrate our hypotheses on the basis of simple experiments was made. It is well-known that cellulose can be dissolved in a aqueous sodium hydroxide (NaOH/H2O) solvent at low temperature but it is here shown that such an alkaline solvent can be considerably improved regarding solubility, stability and rheological properties as a whole if different additives (salts and amphiphilic molecules) are used in the dissolution stage. This work probes new aqueous routes to dissolve cellulose, thereby improving the potential to commercially dissolve cellulose in an inexpensive and environmentally friendly manner.
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| 3. |
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| 4. |
- Siqueira, Fernanda A., et al.
(author)
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Metal-Free Synthesis of Indanes by Iodine(III)-Mediated Ring Contraction of 1,2-Dihydronaphthalenes
- 2011
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In: Journal of the Brazilian Chemical Society. - 0103-5053 .- 1678-4790. ; 22:9, s. 1795-1807
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Journal article (peer-reviewed)abstract
- A metal-free protocol was developed to synthesize indanes by ring contraction of 1,2-dihydronaphthalenes promoted by PhI(OH)OTs (HTIB or Koser’s reagent). This oxidative rearrangement can be performed in several solvents (MeOH, CH3CN, 2,2,2-trifluoroethanol (TFE), 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), and a 1:4 mixture of TFE:CH2Cl2) under mild conditions. The ring contraction diastereoselectively gives functionalized trans-1,3-disubstituted indanes, which are difficult to obtain in synthetic organic chemistry.
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| 5. |
- Da Silva, Maycon R., et al.
(author)
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Identification of two additional behaviorally active gland constituents of female Diatraea saccharalis (Fabricius) (Lepidoptera Crambidae)
- 2021
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In: Journal of the Brazilian Chemical Society. - : Sociedade Brasileira de Quimica (SBQ). - 0103-5053. ; 32:1, s. 225-230
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Journal article (peer-reviewed)abstract
- The sugarcane borer, Diatraea saccharalis (Fabricius), is the major pest insect attacking sugarcane crops in Brazil. Population control by insecticide treatment is not efficient due to simultaneous presence of all developmental stages of the insect throughout the year, and alternative control methods are needed. Two female-produced sex pheromone components, (Z,E)-hexadeca-9,11-dienal and (Z)- hexadec-11-enal, have previously been reported to elicit antennal activity and behavioral response of males in flight tunnel experiments. However, the attractiveness of these compounds in field tests has been very low. In this study, two additional female-produced compounds in D. saccharalis eliciting consistent antennal response in males were identified as (Z)-hexadec-9-enal and hexadecanal. In flight tunnel assays, the behavioral response to a quaternary blend was significantly higher when compared with the previously identified binary blend. Subtracting (Z)-hexadec-9-enal or hexadecanal from the full blend did not reduce attraction, indicating redundancy in the communication channel. We conclude that additional compounds are part of the sex pheromone of D. saccharalis, which may improve the efficiency of trap lures for monitoring of this pest.
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| 6. |
- Olofsson, Gerd, et al.
(author)
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On the use of Titration Calorimetry to Study the Association of Surfactants in Aqueous Solutions
- 2009
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In: Journal of the Brazilian Chemical Society. - 0103-5053. ; 20:4, s. 577-593
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Research review (peer-reviewed)abstract
- Isothermal titration calorimetry is increasingly becoming a common tool for the investigation of surfactant association processes. This can be associated with the development of new, sensitive and easy-to-operate commercial equipment, allied with the advantage of producing simultaneous information on the main thermodynamic parameters associated with the process under investigation. However, a significant fraction of users are still unfamiliar with many aspects related with the use of these calorimetric techniques. This review intends to discuss the design of experiments to investigate surfactant self-assembly in water and in the presence of polymers ( charged and uncharged), as well as on how to derive the most relevant thermodynamic parameters from these calorimetric titration curves. Some literature examples are discussed to illustrate the use of these techniques for different systems.
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