O Laboratório de Ensino de Matemática (LEM) tem sido objeto de estudo de várias pesquisas que buscam apontar as contribuições deste espaço para o ensino e aprendizagem da matemática. Como a maioria dos estudos tem se desenvolvido na direção da importância do LEM na formação inicial e continuada de professores, buscou-se a implementação deste espaço numa Escola de Educação Básica com o objetivo de vislumbrar aspectos significativamente positivos para o ensino da matemática a partir da experimentação destes materiais e instrumentos, além de verificar como seria a receptividade da direção, professores e alunos para esta proposta. Assim, decorridos três anos da sua organização, retornou-se a escola com uma pesquisa a fim de verificar se o laboratório encontrava-se preservado e utilizado por alunos e professores, além de saber quais foram as contribuições para o ensino de matemática. E, transcendendo os objetivos do projeto, constatou-se que a experiência do LEM serviu de trampolim para uma reorganização pedagógica da escola, contemplando laboratórios para as demais áreas do conhecimento. Porém, ficou manifestada a necessidade de formação continuada, a importância de trocar experiências e conhecer materiais que são desenvolvidos e pesquisados pela comunidade acadêmica, buscando um ensino contextualizado, prazeroso e significativo para os alunos.
The interactions between Ph 4 P + cations and p-sulfonatocalix-[n]arene anions offer the possibility of building up new materials based on interactions between the anions and cations beyond their electrostatic attraction, such as the possibility of a phenyl ring of the cation residing in the cavity of the calixarene. In developing this concept, we have embarked on a systematic study of the ability of the Ph 4 P +-psulfonatocalix[n]arene system to generate extensive self-assembled arrays. We report herein the formation of materials built up from Ph 4 P + cations and different sizes calix[n]arenes with n = 4 (see Figure), n = 6 and n = 8.
Gold(I) chloride complexes catalyze a wide range of reactions, in the presence of different silver(I) salts. In particular alkoxycyclization and skeletal rearrangement of 1,6-enynes proceed at room temperature with [Au(PPh 3 ) Cl]/AgSbF 6 . [1] In addition, dienynes and 1,6-enynes with an aryl ring at the alkyne, give [4+2] products in a reaction catalyzed by gold(I) complexes with bulky phosphines. [2] In order to avoid the use of silver salts, we have synthesized new cationic complexes with bulky phosphines. The preparation of this new type of gold(I) compounds involves the reaction with AgSbF 6 in different coordinating solvents. When aromatic solvents are used, a new type of complexes are formed, which show an interaction between the arene and the electrophilic metal center. The structures of these new gold(I) complexes have been studied by X-ray diffraction.[1] Nieto-Oberhuber C., MuñozM. P., Buñuel E., Nevado C., Cárdenas D.J., Echavarren A.M., Angew. Chem. Int. Ed., 2004, 43, 2402-2406 Recently a spectacular development of a new generation "nonmetallocene" catalysts have been designed and several systems capable of catalyzing the living polymerization of olefins was made. Alternatively, this kind of compounds also provided convenient routes to synthetic applications by unsaturated organic derivatives coupling reactions, via metallacyclic intermediates.The broad success of early transition metal based organic synthesis is due in part to the unique ability of the metal to activate ligands to which it is directly bound through organometallic transformations than are often highly chemo-, regio-and stereoselective processes. In the group 5, niobium and tantalum alkynes complexes, via metallacyclic compounds, have provided good examples of that behaviour [1].We report herein the synthesis and the structural study of monocyclopentadienyl alkyl and chloro azatantalacyclo-propane,-pentane and -pentene derivatives, their reactivity in the insertion of isocyanides and the intramolecular rearrangements processes observed in the resulting complexes. Comparative studies with the alkyl Niobium complexes will be presented .[1] Galakhov M., Gómez M., Gómez-Sal P., Velasco P. In 1999 we reported the synthesis of cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane, which was obtained by an intramolecular [2+2] photocycloaddition reaction.[1] A similar template effect has been exploit in a Pd(II) complex, promoting an asymmetric [4+2] Diels-Alder reaction. [2] In order to synthesize cis,cis-1,2,3,4-tetrakis(diphenylphosphino)butadiene (dppbd), a bis-bidentate tetraphosphine ligand with a conjugated backbone, we designed a synthesis, which comprises three steps. The first step is the synthesis of the mixed bridged Pt(II) compound [Pt 2 Cl 2 (dppa)(t-dppen)] containing trans-1,2-bis(diphenylphosphino)ethene (t-dppen) and bis(diphenylphosphino)acethylene (dppa). In the second step a [2+2] photocycloaddition reaction takes place, where a phosphine substituted cyclobutene is formed, which is not stable under these...
Este livro congrega diferentes práticas de ensino e aprendizagem que promovem aulas de matemática dinâmicas e prazerosas. É resultado do trabalho desenvolvido sob a orientação das docentes organizadoras deste livro, no Componente Prática de Ensino da Matemática VIII, com os alunos formandos do oitavo semestre da turma Mat T8/2019. Tais propostas foram vivenciadas por professores de anos iniciais da rede pública através do projeto de extensão acadêmica: “A educação matemática nas séries iniciais do ensino fundamental: repensando a prática docente a partir da Base Nacional Comum Curricular”. Neste sentido, este livro simboliza o esforço conjunto para garantir que todas as crianças tenham direito de aprender conceitos matemáticos de forma ativa e significativa, oportunizados a partir de um contexto escolar lúdico e que desperte a autonomia e a criatividade infantil. Desejamos uma inspiradora leitura.
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