Study of the synthesis and characterization of Benzyl Isothiocyanate derivatives: Problematized Experimental Activity
Name: LÍLIA DO ESPÍRITO SANTO AZEVEDO DE OLIVEIRA
Publication date: 01/10/2025
Examining board:
Name |
Role |
|---|---|
| RICARDO MACHADO KUSTER | Examinador Interno |
Pages
Summary: This thesis investigated how the synthesis and characterization of benzyl isothiocyanate (BITC) derivatives can be didactically transposed to higher education in Chemistry through the Problematized Experimental Activity (AEP), aiming for meaningful learning (ML) and the balanced development of analytical, creative, and practical abilities. The study adopted a sequential mixed-methods design, articulating two interdependent phases: experimental and educational. In the experimental phase, thiosemicarbazides (TSCs) and thioureas (TUs) derived from BITC were synthesized and characterized, with their structures confirmed by elemental analysis (CHN), mass spectrometry (MS), infrared spectroscopy (IR), ¹H and ¹³C nuclear magnetic resonance (NMR), single-crystal X-ray diffraction of three of the derivatives, and determination of antioxidant capacity by the FRAP (Ferric Reducing Antioxidant Power) assay. Using TSCs as ligands, a series of coordination compounds was obtained by reaction with Co(II) and Cu(II) salts, whose structures could not be precisely elucidated due to the insolubility of the solids. In the case of the TUs, two coordination compounds were obtained, one of Co(III) and another of Cu(I), from the derivatives TU_45 and TU_2, respectively, which had their structures determined by single-crystal X-ray diffraction. In the educational phase, the laboratory results were transposed into pedagogical interventions organized according to the AEP model, applied to undergraduate Chemistry students from three classes in different modalities. The collection of qualitative and quantitative data involved the characterization of the participants' profile, prior knowledge questionnaires, reports and experimental worksheets, knowledge systematization products, and metacognitive indicators of cognitive development (IMDCs). The results indicated conceptual evolution among the students, advances in the articulation between theory and practice, and the development of the three intelligence capabilities, with a greater mobilization of these during the systematization stage. Such results suggest that the AEP promoted ML and contributed to the formation of reflective teachers capable of transposing scientific knowledge into contextualized teaching proposals. Thus, in the experimental field, the feasibility of obtaining and characterizing BITC derivatives and associated coordination compounds was evidenced, with potential for future investigations on structure-property correlations and therapeutic applications. And, in the educational field, the research demonstrated the potential of AEP as an articulating axis between science and teaching, constituting a consistent didactic transposition (DT) strategy, with theoretical, methodological, and practical implications for initial training in Chemistry.
