Volume 38, Número 1, 2015

ISSN:0100-4042ISSN:1678-7064 on line

22 Efeito da estrutura molecular de ligantes de superfície em pontos quânticos de CdTe dispersos em água

Brener R. C. Vale, Kayo O. Vieira, José C. L. Sousa,

Jefferson L. Ferrari e Marco A. Schiavon

With increasing particle sizes of water-soluble mercaptoethylamine-capped CdTe, the trap band energy stabilizes until the material reaches a critical size. Thereafter, the TB is not observed in the photoluminescence spectra.

14 Biofilms based on canihua flour (Chenopodium Pallidicaule): design and characterization

Lady M. Salas-Valero, Delia R. Tapia-Blácido and Florencia C. Menegalli

The flours isolated from canihua grains (Chenopodium Pallidicaule) can form films that have low water vapor permeability and act as a good barrier to incident ultraviolet light. Films formed from both varieties of canihua grains used in this study (cupi and illpa-inia) presented a single vitreous transition temperature (< 0 °C) and show promise for potential applications in food packaging.

8 The application of automated correlation optimized warp-ing to the quality evaluation of Radix Puerariae thomsonii: correcting retention time shift in the chromatographic fin-gerprints

Long Jiao, Shan Bing, Xiaofei Wang, Zhiwei Xue and Hua Li

Automated correlation optimized warping is a practical method for aligning the chromatographic fingerprints of Radix Puerariae thomsonii. After this alignment, the quality of Radix Puerariae thomsonii can be correctly evaluated.

1 A influência da ligação de hidrogênio em reações químicas: reação de Prileschajew

Mauro A. Bueno e Boaz G. Oliveira

The epoxidation mechanism known as the Prileschajew reaction was reinvestigated through the formation of hydrogen bonds between C2H4O and HCO2H.

Artigo

iv Quim. Nova

37 Di-hidrocucurbitacina B: semi-síntese de novos derivados glicosilados

Vanessa R. Machado, Karen L. Lang, Fernando J. Durán, Gabriela M. Cabrera, Jorge A. Palermo, Eloir P. Schenkel e Lílian S. C. Bernardes

30 Distribuição e fracionamento do Hg em sedimentos do Rio Paraíba do Sul – RJ, Brasil

Beatriz F. Araujo, Marcelo G. de Almeida, Thiago P. Rangel e Carlos E. de Rezende

42 Chemical study of Hortia superba (Rutaceae) and investiga-tion of the antimycobacterial activity of crude extracts and constituents isolated from Hortia species

Vanessa G. P. Severino, Afif F. Monteiro, Mª Fátima das G. F. da Silva, Rodrigo Lucarini and Carlos H. G. Martins

46 Esterificação e transesterificação simultâneas de óleos ácidos utilizando carboxilatos lamelares de zinco como catalisadores bifuncionais

Luiz P. Ramos, Ricardo J. Brugnago, Fabiano R. da Silva, Claudiney S. Cordeiro e Fernando Wypych

Novel glycoside derivatives of dihydrocucurbitacin B were synthesized under Köenigs-Knorr and imidate reaction conditions.

Our results confirm the key role played by mangroves in controlling the fate of mercurial compounds in coastal areas. Consequently, mangrove deforestation should be considered a major source of environmental risk in tropical and subtropical coastal regions.

The picture describes the methodology used in the biological evaluation of Hortia species against Mycobacterium tuberculosis H37Rv, M. kansasii and M. avium, and the compounds that exhibited promising MIC values against M. tuberculosis H37Rv.

Response surface demonstrating the ability of zinc carboxylates to promote the simultaneous esterification and transesterification of palm oil with 40% in free fatty acids.

vVol. 38, No. 1

60 Novos flavonoides de Margaritopsis carrascoana com ati-vidade antioxidante

Raimundo R. G. Nascimento, Jackelyne A. Monteiro, Antônia T. A. Pimenta, Mª Teresa S. Trevisan, Raimundo Braz-Filho, Elnatan B. de Souza, Edilberto R. Silveira e Mary A. S. Lima

55 Influência do tratamento térmico no nanocompósito fotoca-talisador ZnO/TiO2

Mª Terezinha C. Sansiviero e Dalva L. A. de Faria

66 Volatile components from galls induced by Baccharopelma dracunculifoliae (Hemiptera: Psyllidae) on leaves of Bac-charis dracunculifolia (Asteraceae)

Michele A. Besten, Domingos S. Nunes, Daniel Granato, Sávio L. Sens, Alberto Wisniewski Jr, Edesio L. Simionatto and Dilamara Riva-Scharf

71 Global and local reactivity descriptors for picloram herbicide: a theoretical quantum study

Luis H. Mendoza-Huizar

Two new flavonoids and other known compounds were obtained from extracts of the leaves and stems of Margaritopsis carrascoana. All isolated compounds showed higher antioxidant activity, while the extract of the stems showed strong AChE inhibition.

ZnO/TiO2 nanocomposites were treated at different temperatures, and anatase, ZnO, and ZnTiO3 were formed when the sample was heated at 600 °C, whereas the main phases obtained above 750 °C were rutile and ZnTiO3. The presence of ZnTiO3 in the sample had no significant effect on the nanocomposite photocatalytic activity.

This article presents the first GC-MS analyses of volatiles from galls induced by Baccharopelma dracunculifoliae and the results are compared with those from healthy Baccharis dracunculifolia leaf samples.

The most reactive sites on picloram for electrophilic, free radical, and nucleophilic attacks have been determined.

vi Quim. Nova

85 Investigação do uso de eletrodo de carbono vítreo modificado com hexacianoferrato de rutênio para detecção de procaína

Thalita G. Silva, Maiara O. Salles e Thiago R. L. C. Paixão

77 Avaliação de métodos de solubilização para determinação de metais em glicerina proveniente da produção de biodiesel por técnicas de espectrometria atômica

Caroline D. Clasen, Meibel T. Lisboa, Ane M. T. P. Pinto, Anderson S. Ribeiro e Mariana A. Vieira

91 Nanopartículas de proteína isolada de soja em água: efeito da força iônica e das concentrações de proteína e surfactante

Samira J. Fayad, Betina G. Z. Ramos, Valdir Soldi e Edson Minatti

97 A versatilidade dos compostos de coordenação na produção de polietilenos: uma revisão dos sistemas catalíticos

Emanoel I. da S. Oliveira, Fernando Silveira, Adelaide Mª V. Viveiros, Nara R. S. Basso, Zênis N. da Rocha e João H. Z. dos Santos

The use of a glassy carbon electrode modified with ruthenium hexacyanoferrate was investigated. The aim was to detect procaine in abused drugs and pharmaceutical formulations.

Evaluation by atomic spectrometry of simple and fast solubilization methods for the determination of Ca, Mg, and K in glycerin samples obtained from biodiesel production.

Soy protein isolate nanoparticles were obtained through the coacervation of an aqueous protein solution. Morphology and stability analyses were followed by light scattering and microscopy analyses.

Various types of polyethylene can only be obtained because of the possibility of modulating coordination compounds used as catalysts in the polymerization process. Both the metal center and the ligands can be tuned, giving versatility to such systems.

Revisão

viiVol. 38, No. 1

118 Arsênio e arroz: toxicidade, metabolismo e segurança ali-mentar

Juliana M. O. Souza, Maria F. H. Carneiro, Ana C. C. Paulelli, Denise Grotto, Ariano M. Magalhães Júnior, Fernando Barbosa Júnior e Bruno L. Batista

Rice plants have the tendency to absorb different arsenic species. This cereal is a staple food for half of the global population. According to FAO/WHO, the arsenic level of rice is an increasing concern in food safety. Understanding the plant’s mechanisms and monitoring its safety are imperative.

106 Óxidos de nióbio: uma visão sobre a síntese do Nb2O5 e sua aplicação em fotocatálise heterogênea

Osmando F. Lopes, Vagner R. de Mendonça, Fernando B. F. Silva, Elaine C. Paris e Caue Ribeiro

The following scheme depicts the application sequence of niobium oxide nanoparticles from an appropriate Nb source to heterogeneous photocatalysis. Aspects such as the morphology, band gap, and surface area are defined by the nanoparticles’ synthetic parameters, which also influence the catalyst performance.

128 Construção de um reator de plasma descarga corona para eliminação de compostos orgânicos voláteis

Marina M. Machado, Marília M. Machado, Ana R. de A. Dutra, Elisa H. S. Moecke e Anelise L. V. Cubas

A cold plasma reactor was built with low-cost materials in order to degrade volatile organic compounds such as BTEX, known for their adverse effects on human health.

132 Construção de um dispositivo de pressurização a vácuo para a preparação de fases estacionárias monolíticas via processo sol-gel

Sandro P. Ribeiro, Fernando A. S. Vaz, Marcone A. L. de Oliveira, Thiago de O. Mendes e José P. R. F. de Mendonça

This high pressurization device allows the capillary to be filled with a sol solution through either positive or negative (vacuum) pressure. The latter procedure averts contact between sol and the syringe thus avoiding damage.

Nota Técnica

viii Quim. Nova

159 Comentário sobre o artigo: “Modificação do polímero condutor polianilina para uso como trocador catiônico”

160 Adsorption of a copper (II) complex on calcium phosphate intercalated with 4-aminobenzoic acid – synthesis and electrochemical investigation Quimica Nova, Vol. 36, No. 8, 1170-1175, 2013

Camila F. N. Silva, Fernando M. de Souza, Jéssica P. Santos, Ana Paula B. Dias, Ana Paula R. Santana, Angélica M. Lazarin, Rosana L. Sernaglia, Elza I. S. Andreotti and Claudio Airoldi

Educação

Carta ao Editor

Retraction Notice

144 A formação de professores em comunidades de prática: o caso de um grupo de professores de química em formação inicial

Valéria C. Santos e Agnaldo Arroio

This graphical abstract outlines the main elements of the research. The group represents a community of practice in chemistry teaching.

136 Aparato eletroquímico para sistema de aquisição de dados multicanal com resolução espaço-temporal

Raphael Nagao, Melke A. Nascimento e Hamilton Varela

An electrochemical setup for a multichannel data acquisition system was developed in order to obtain spatiotemporal resolution during the electro-oxidation of small organic molecules.

151 Avoiding first-year university chemistry textbooks’ misre-presentations in the teaching of spontaneous reactions

Ana Quílez-Díaz and Juan Quílez-Pardo

The calculation (and the sign) of DrG establishes the direction of a chemical reaction. Q–K inequalities are accurate options. However, the use of the sign of DrGº or Le Châtelier’s principle leads to incorrect predictions.

156 Método de síntese de azidas aromáticas usando vinagreKauanna N. Hino e Álvaro T. Omori

A simple and low-cost procedure for preparation of aryl azides is described. Vinegar (renewable source) can be used as solvent/reagent.