Orbital: The Electronic Journal of Chemistry

Cooperation of Peripheral Hydrogen Atoms for the Stabilization of Aachno-pentaborane (11) with Small Molecules: Hydrogen Bonds and Dihydrogen Bonds

2023-07-17T02:12:55+00:00

Post-Hartree-Fock calculations performed at the MP2/aug-cc-pVDZ level of theory has been used to analyze the formation of intermolecular complexes between B₅H₁₁ and W = CO, NCH, NH₃, H₂O or HOCH₃. The interactions on the structure of the arachno-pentaborane(11) are manifested by the terminal and bridge hydrogen atoms, whereby are formed the hydrogen bonds (H∙∙∙Y with Y = O, C or N) as well as dihydrogen bonds (H∙∙∙H). In this context, the B₅H₁₁ shows a host-guest capability for trapping molecules, of course depending on the strength of each aforementioned interactions. The topological descriptors of the Quantum Theory of Atoms in Molecules (QTAIM) were decisive for unveiling each one of the following structures B₅H₁₁∙∙∙CO, B₅H₁₁∙∙∙NCH, B₅H₁₁∙∙∙NH₃, B₅H₁₁∙∙∙H₂O and B5H₁₁∙∙∙HOCH₃, and ideally, all hydrogen bonding formed by them.

Green Synthesis and Anti-microbial Activities of Some Thiazole-imino Derivatives

2023-07-17T02:12:49+00:00

The ring forming reaction of furfural imine (A) and substituted acetophenone (B) via a greener approach resulted in the synthesis of thiazole-imino derivatives (C1 – C5). The compound A was synthesized by green method using acetic acid in aqueous media where conc. Sulfuric acid was avoided. The final compounds (C1-C5) were again synthesized in aqueous media avoiding use of organic solvents. The resultant compounds were characterized and distinguished from their precursors by elemental analysis, ¹H-NMR, ¹³C-NMR and IR spectral studies. The in-vitro activities of the final compounds (C1-C5) depicted that they are all appreciably active against bacterial strains S. aureus, B. subtilis and fungal strains C. albicans, C. glabrata. Ciprofloxacin and Itraconazole were used as the control drugs for anti-bacterial and for anti-fungal activities; respectively. As compared to the other analogues, compound C2 (R = NO₂) and C4 (R = Cl) showed best activities against the bacterial and fungal strains; respectively.

Studies on the Optical and Photoelectric Properties of Anthocyanin and Chlorophyll as Dihybrid Sensitizer in Dye Sensitized Solar Cell (DSSC)

2023-07-17T02:12:43+00:00

The production costs and energy conversion efficiency of dye-sensitized solar cells (DSSC) is strongly influenced by the types of dyes used to harvest photons. Natural dyes extracted from different pigments are emerged as a potential dye to enhance the efficiency of DSSC due to their merit properties such as low cost, biodegradable and less environmental concern. Natural pigments were derived from Eleiodoxa conferta (E. conferta) and Spinacia oleracea (S. oleracea) and formation of a mixture of these extracts in (1:1) volume ratio. The dihybrid extract displayed a diverse UV-vis absorption spectrum of 530–550 nm with maximum absorption at ~539 nm. The optical features of the harvested dyes and the photovoltaic productivity of the cells have been explored. The photovoltaic output of the dihybrid delivered the best findings with open-circuit voltage (V_OC), short-circuit current density (J_SC), fill factor (FF) and energy conversion efficiency values of 0.35 V, 5.83 mA/cm², 0.63 and 1.29 % respectively.

1,2-O-Isopropylidene-3-O-butylglucofuranose-derived Ester, and Ether: Synthesis, Characterization, and Antimicrobial Study

2023-07-17T02:12:37+00:00

Sugar-fatty acid esters (SFAEs, especially sucrose- and glucose-based ones) have dominated the chemical industries for more than 50 years. In comparison to other carbohydrate products, SFAEs serve essential roles in a variety of industries, including the food, pharmaceutical, and cosmetic industries. In this context, the 6-O-hexanoyl ester of 3-O-butyl-1,2-O-isopropylidene-α-D-glucofuranose was synthesized from commercially available D-glucose in a few steps. For a comparative biological study, the 5,6-di-O-benzyl ether of 3-O-butyl-1,2-O-isopropylidene-α-D-glucofuranose was also prepared and characterized. An in vitro antimicrobial test of all the ester and ether compounds indicated that these compounds are more susceptible to fungi than bacteria. Also, they have more potential for A. niger than A. flavus. According to Prediction of Spectra for Substances (PASS), the chemicals found in the current investigation have a variety of potential biological functions.

Structural, Morphological and Physical Characterization of Carbon Fly Ash

2023-07-17T02:12:32+00:00

Carbon fly ash (CFA) is the principal industrial waste byproduct from the burning fossil fuel (coal combustion) for the thermal generation of electricity. CFA is a gray or black powdery solid that is constituted mostly metal oxides (Al, Si Fe and Ca), unburned carbon (UC) and other inorganic substance. The management of fly ash has thus been a matter of concern given the requirement of the large area of land for its disposal and potential of causing pollution of air, water, land and effects on human health. Physical and chemical characteristics of fly ash is important, as these characteristics influence its subsequent use and disposal. X-ray diffraction, and fluorescence, scanning microscopy with an energy dispersive spectroscopy, FTIR, BET was the common techniques employed to characterize FA. Characterization by XRD analysis identified the presence of quartz, mullite and sillimanite phases; while the FTIR results allowed the identification of vibrational bands, characteristic of Si-O-Si and Si-O bonds. The EDS analysis coupled to SEM allowed verifying that the composition of the samples is consistent with the results sought and that the morphological characteristics validate the proposed methodology. Surface area analyses (BET) showed that the fly ash possess an active area of 6.02 m² · g^-1.

Comparative Study of Fatty Acid Composition in Crude Vegetable Oils from Species Cultivated in Mato Grosso do Sul, Brazil

2023-07-18T19:05:16+00:00

Soybean is the main oilseed cultivated in the Middle-west region of Brazil, once geoclimatic conditions favor its cultivation and underexplored species such as crambe, oilseed radish, and niger too. These species can be alternatives to eliminate the conflict between food and energy production, so the study aimed to evaluate and compare the fatty acids content of soybean, crambe, oilseed radish and niger oils by gas chromatography with flame ionization detector using two quantification methods, followed by multivariate statistical analysis to determine the similarity between the selected species and to provide safe information for the best selection and application of these oilseeds. The oil content in crambe, oilseed radish and niger seeds were 44.7% (m/m), 42.45% (m/m) and 28.19% (m/m), respectively. The major fatty acid in niger and soybean oils was linoleic acid (66.9% and 52.07% m/m, respectively), in crambe and oilseed radish was erucic acid (65.29% and 33.54% m/m, respectively). In addition, for saturated fatty acids, the presence is minor (<17%), except for niger seeds with 19.5% (m/m). Niger oil has greater similarity with soybean oil, whereas crambe and oilseed radish oils are more similar to each other. In this way, it was possible to discriminate the different fatty acids present in the oil samples by the proposed method contributing to the objective of the study and enabling better decision-making in the context like biofuels production.

Scavenging Activity on Reactive Oxygen Species with Biological Relevance by Varronia curassavica

2023-07-17T02:12:16+00:00

Varronia curassavica Jacq. is a medicinal plant found in Brazil used as anti-inflammatory. Here, we investigated the in vitro antioxidant activity of 70 % ethanol extract of V. curassavica leaves on synthetic radicals (ABTS^•+/DPPH^•) and reactive oxygen species (O₂^•-, ROO^•, HOCl/OCl^-, H₂O₂), besides its in vitro cytotoxicity. The extract was characterized by UPLC-ESI-QToF-MS^E and the annotated compounds were one hydroxybenzoic acid, five phenylpropanoids, and three glycosylated quercetin derivatives, being the main compound rosmarinic acid or its isomer. The antioxidant activity was very promising in all tests, highlighting on the capture of O^2•-, which EC₅₀ value was three times lower than Trolox. This activity may be due to the presence of the major compounds, all phenolic compounds. The extract also presented low cytotoxicity. Thus, the extract from V. curassavica leaves has great potential as an antioxidant.

Development and Implementation of Augmented Reality-Based Card Game Learning Media with Environmental Literacy in Improving Students' Understanding of Carbon Compounds

2023-07-17T02:23:11+00:00

The lack of knowledge integration about the learning environment is one of the causes of the low environmental awareness. The purpose of this study was to develop learning media for carbon compounds based on augmented reality and environmental literacy and to find out student learning outcomes after using media, students' perceptions of the media, and their environmental insight. This research is a research and development (R&D) research by following the ADDIE model. One group pre-test post-test research design was used to examine the effect of using the media. The research instruments were multiple choice test, questionnaires, and interviews which were developed independently and tested for validity & reliability. The analysis technique was the paired sample t-test and content analysis. The results of this study showed that the learning media was very eligible with a validation score reaching 88.1%. The result of the implementation of the final product of ChemiCa shows that there is an impact of using media on student learning outcomes (Sig. 0.000<0.05). Students' perception of the media are very good, learning media can increase their understanding of carbon compounds concepts, as well as their motivation to learn chemistry. This study implies that teachers can use augmented reality-based card game as a supplementary learning media to improve students’ understanding of others relevant chemistry concepts and their environment literacy.

Development of Articulate Storyline 3-Based Digital Teaching Materials on the Subject of Atomic Structure and Periodic Elements System for SMA/MA Students in Class X

2023-07-17T02:28:26+00:00

The articulate storyline 3 application is a multimedia authoring tool used to create interactive learning media with content from a combination of text, images, graphics, sound, animation, and video that is usable on various devices such as laptops, tablets, and smartphones. Teaching materials developed based on articulate storyline 3 can help independent learning. The development model used as a reference in this study is the Borg and Gall model which consists of 5 stages: preliminary studies, design and development, design validation and revision, product trial, and final product dissemination. The results of the assessment of material and media experts on the level of validity of digital teaching materials have a very valid category with a percentage of validity throughout the whole at 87.95% and 93.3%, respectively. The student response to the digital teaching material during the trial was very positive, with an average overall percentage of 95.71% in small-group trials and 95% in large-group trials. Thus, digital teaching materials based on Articulate Storyline 3 on the subject matter of atomic structure and periodic systems of these elements are suitable for use in chemistry learning activities as a source of independent learning and learning media.