Concepts In Organic Chemistry Research Articles

A Contemporary Introduction to Essential Oils: Chemistry, Bioactivity and Prospects for Australian Agriculture

This review is a comprehensive introduction to pertinent aspects of the extraction methodology, chemistry, analysis and pharmacology of essential oils, whilst providing a background of general organic chemistry concepts to readers from non-chemistry oriented backgrounds. Furthermore, it describes the historical aspects of essential oil research whilst exploring contentious issues of terminology. This follows with an examination of essential oil producing plants in the Australian context with particular attention to Aboriginal custom use, historical successes and contemporary commercial prospects. Due to the harsh dry environment of the Australian landmass, particularly to the cyclical climatic variation attendant upon repeated glaciation/post-glaciation cycles, the arid regions have evolved a rich assortment of unique endemic essential oil yielding plants. Though some of these aromatic plants (particularly myrtaceous species) have given birth to commercially valuable industries, much remains to be discovered. Given the market potential, it is likely that recent discoveries in our laboratory and elsewhere will lead to new product development. This review concludes with an emphasis on the use of chemotaxonomy in selection of commercially viable cultivar chemotypes from the Australian continent. Finally, drawing largely from our own results we propose a list of Australian endemic species with novel commercial potential.

International Organic Chemistry Competition: A Thrilling, Unique Experience

The introduction of clickers into the learning environment evolved significantly reflecting major developments in student academic performance. From simple in-class, multiple-choice questions to global international competitions, this innovative tool has managed to combine both education and entertainment into an intuitive and positively reinforcing learning experience. In 2011, the PI was appointed by the International Union of Pure and Applied Chemistry (IUPAC) to represent and coordinate the activities in Lebanon in celebration of the International Year of Chemistry (IYC2011). The first seed of organic chemistry competition (OC) was thus planted, sparking a series of more successful events promoting a fun and proactive educational environment that recognized the participants’ mastery of essential concepts of organic chemistry. As such, the OC has since became a platform for higher education and student-based academic involvement joining students from all around the world and different walks of life to experience and share a common interest: organic chemistry.

QCISD(T) Insight on the Electronic Structure of C3N2 Conjugated Skeletons

Abstract Tautomerism is an important concept in organic chemistry and a key element in many applications. This motivated us in this study to investigate the electronic structure of the conjugated NCCCN skeleton by studying the properties of malonaldimine as the simplest form. The analysis confirms that the π-system allows efficient electron density flow (delocalization). On the other hand, this skeleton features a valuable energy barrier for the hydrogen-bridge form. These two characteristics are corner stones for designing unsymmetrically functionalized skeletons for molecular switching and signaling.

Paul von Ragué Schleyer (1930-2014).

Paul von Ragué Schleyer, Graham Perdue Professor at the University of Georgia passed away on November 21, 2014. Schleyer was an eminent and prolific physical organic chemist, whose pioneering contributions included the application of computational chemistry to broad fields of physical organic, inorganic, organometallic, and mechanistic chemistry concepts.

Theoretical Advances in Aromatic Nitration

In this paper we want to present together our theoretical findings on aromatic nitration, involving both homocyclic and heterocyclic compounds. Our theoretical proposals have been introduced in recent years via several research communications. These theories convey new concepts in Organic Chemistry, such as Electric Hindrance, Autogenic Electromeric Effect, the formation of Precursor Complexes, as well as, short- and long-distance electric interactions in the reactive intermediates. These concepts explain the regiochemistry and the reaction yields, clearing up some obscurities found in Organic Chemistry. Thus, these theoretical considerations are filling gaps in the theory of supposedly well known chemical reactions, improving and updating the Chemical Education.

The influence of instructional method on students' achievement and mental effort: Systemic versus traditional approach in secondary organic chemistry teaching

Organic chemistry is the chemical discipline that many secondary school students find abstract and difficult. As a result, they learn organic chemistry concepts in a 'rote' way. Therefore, the first goal of this study was to examine whether the systemic approach, that implies the application of systemic synthesis questions, [SSynQs], as new instructional tools, could help students in overcoming these difficulties. The results of this study have shown that students from the experimental group, who were exposed to the new instructional method, achieved higher scores on final testing than students from the control group, who were taught by traditional method, when students' achievements in conventional linear questions, [LQs], and systemic synthesis question, [SSynQs], were evaluated. These findings were followed by the reduction of levels of invested mental effort of the students from experimental group, estimated during solving both types of test questions. Additionally, it was confirmed that students from both examined groups find systemic synthesis question, [SSynQs], more difficult to solve than linear questions, [LQs], achieving lower scores and perceiving higher levels of mental effort. These research findings were explained by completion problems effect which is often discussed within cognitive load theory. Having this in mind, the next step in our research would be to examine the influence of variability effect on students' ability to solve systemic synthesis question, [SSynQs].

Using Commercially Available Techniques To Make Organic Chemistry Representations Tactile and More Accessible to Students with Blindness or Low Vision

Organic chemistry courses can present major obstacles to access for students with blindness or low vision (BLV). In recent years, efforts have been made to represent organic chemistry concepts in tactile forms for blind students. These methodologies are described in this manuscript. Further work being done at Illinois State University is also described that allows a student with BLV to independently make properly Braille labeled structures from the organic chemistry online database via ChemDraw.

Assignment of aromaticity of the classic heterobenzenes by three aromatic criteria

Aromaticity is a key concept in physical organic chemistry. The aromatic order of the classic heterobenzenes was reported in experiment early. However, the unambiguous criteria used to validate the aromaticity of that were controversial or inadequate in theory. In this work, the global aromaticity of the compounds has been studied using the ELF, NICS and ISE. NICS(max)zz was calculated based on the maximum NICS contribution to the out-of-plane zz tensor component. Two types of bonds are observed. The correlations between NICS(max)σzz and NICS(max)πzz with respect to aromaticity are demonstrated, specifically between NICS(max)πzz and ELFπ (cc=0.98) for π bonds. For σ bonds, the different electron delocalization of σ bonds out of the plane of the ring predicted well the discrepancies between NICS(max)σzz and ELFσ. The σ aromatic order of the classic heterobenzenes (C5H5N>C6H6>C5H5P>C5H5As>C5H5Bi, C5H5Sb) was proved via the level of electronic delocalization.

Using Web-Based Video as an Assessment Tool for Student Performance in Organic Chemistry

This article shows the potential for using video responses to specific questions as part of the assessment process in an organic chemistry class. These exercises have been used with a postbaccalaureate cohort of 40 students, learning in an online environment, over a period of four years. A second cohort of 25 second-year students taking the organic chemistry course onsite has been using these exercises over a period of three years. The questions in this exercise require the students to use a molecular model kit. The problems presented to the students involve standard concepts in organic chemistry relating to geometric issues with molecules or organic reactions. This method of assessment allows the instructor to see a student’s higher-order thinking on a particular topic to a greater degree than is generally afforded with clicker questions. Students are acclimated to this new environment for assessment through practice exercises that are evaluated and critiqued, but not counted towards a grade. A transitio...

A Metal‐Bridged Tricyclic Aromatic System: Synthesis of Osmium Polycyclic Aromatic Complexes

AbstractAromaticity is one of the most important concepts in organic chemistry. A variety of metalla‐aromatic compounds have been recently prepared and in most of those examples, the metal participates only in a monocyclic ring. In contrast, metal‐bridged bicyclic aromatic molecules, in which a metal is shared between two aromatic rings, have been less developed. Herein, we report the first metal‐bridged tricyclic aromatic system, in which the metal center is shared by three aromatic five‐membered rings. These metalla‐aromatics are formed by reaction between osmapentalyne and arene nucleophiles. Experimental results and theoretical calculations reveal that the three five‐membered rings around the osmium center are aromatic. In addition, the broad absorption bands in the UV/Vis absorption spectra of these novel aromatic systems cover almost the entire visible region. This straightforward synthetic strategy may be extended to the synthesis of other metal‐bridged polycyclic aromatics.

A metal-bridged tricyclic aromatic system: synthesis of osmium polycyclic aromatic complexes.

Aromaticity is one of the most important concepts in organic chemistry. A variety of metalla-aromatic compounds have been recently prepared and in most of those examples, the metal participates only in a monocyclic ring. In contrast, metal-bridged bicyclic aromatic molecules, in which a metal is shared between two aromatic rings, have been less developed. Herein, we report the first metal-bridged tricyclic aromatic system, in which the metal center is shared by three aromatic five-membered rings. These metalla-aromatics are formed by reaction between osmapentalyne and arene nucleophiles. Experimental results and theoretical calculations reveal that the three five-membered rings around the osmium center are aromatic. In addition, the broad absorption bands in the UV/Vis absorption spectra of these novel aromatic systems cover almost the entire visible region. This straightforward synthetic strategy may be extended to the synthesis of other metal-bridged polycyclic aromatics.

Identification Experiment of Hydroxy Acids for High School Students: Based on Their Organic Chemistry Concepts

Identification Experiment of Hydroxy Acids for High School Students: Based on Their Organic Chemistry Concepts

Medical Mycology and the Chemistry Classroom: Germinating Student Interest in Organic Chemistry

Efforts to provide active research context to introductory courses in basic sciences are likely to better engage learners and provide a framework for relevant concepts. A simple teaching and learning experiment was conducted to use concepts in organic chemistry to solve problems in the life sciences. Bryant University is a liberal arts university with new programs in biological and environmental sciences. This laboratory exercise was developed for introductory organic chemistry and designed to highlight its applicability to the biological sciences. Students participated in an ongoing project to identify antigens on the surface of Candida albicans hyphae by testing a variety of lipid extraction procedures and characterizing the fatty acid and carbohydrate composition of their extractions by thin-layer chromatography and gas chromatography–mass spectrometry. Student extracts were also tested in an immunoblot assay with a specific antibody fragment (scFv) that recognizes an unknown component of the cell surface of C. albicans hyphae. In order to build communication skills, students were required to prepare and present posters detailing the project and their findings.

Meaningful Understanding and Systems Thinking in Organic Chemistry: Validating Measurement and Exploring Relationships

The purpose of this study was dual: First, to develop and validate assessment schemes for assessing 11th grade students’ meaningful understanding of organic chemistry concepts, as well as their systems thinking skills in the domain. Second, to explore the relationship between the two constructs of interest based on students’ performance on the applied assessment framework. For this purpose, (a) various types of objective assessment questions were developed and evaluated for assessing meaningful understanding, (b) a specific type of systemic assessment questions (SAQs) was developed and evaluated for assessing systems thinking skills, and (c) the association between students’ responses on the applied assessment schemes was explored. The results indicated that properly designed objective questions can effectively capture aspects of students’ meaningful understanding. It was also found that the SAQs can elicit systems thinking skills in the context of a formalistic systems thinking theoretical approach. Moreover, a significant relationship was observed between students’ responses on the two assessment strategies. This research provides evidence that students’ systems thinking level within a science domain is significantly related to their meaningful understanding of relative science concepts.

Preparação de derivados do lapachol em meio ácido e em meio básico: uma proposta de experimentos para a disciplina de Química Orgânica Experimental

In this educational paper we describe the extraction of lapachol from its natural source according to acid-base concepts in organic chemistry and the use of its derivatives β-lapachone and hydroxy-hydrolapachol to exemplify intramolecular cyclization, carbocation stability, Michael addition reaction and chromatography. The experiments were performed during three different undergraduate organic chemistry laboratory classes using low cost material, while avoiding color reagents for TLC visualization, as well as small-scale column chromatography to isolate the mixture of lapachol and β-lapachone.

ConfChem Conference on Case-Based Studies in Chemical Education: Case Study Teaching in the Community College

Students attending community colleges are largely from local communities and of a wide range of age, experiences, and academic preparedness. Those taking chemistry courses are not usually intending careers in chemistry, and many do not have an innate passion or even interest for the subject. I have found that the majority of my students are not particularly receptive to seemingly abstract concepts taught via lectures with PowerPoint presentations that accompany textbooks. They do not often see the relevance of many of the core concepts covered in chemistry textbooks to their own lives and intended careers, and this often leads to perfunctory participation and poor performance. I have found that engaging case studies can be used to connect with these students and also teach core concepts in chemistry. My experiences developing and using case studies to connect with urban community college students and teach core concepts in organic chemistry and general, organic, and biological chemistry (GOB) are described. The cases include concepts pertaining to the mechanisms underlying liver toxicity of acetaminophen, the chemistry of curcumin, the chemistry of cocaine, the chemistry of commonly used painkillers, calorific values of foods, and the chemical principles underlying methemoglobinemia.

Investigando cinza da casca do arroz como fase estacionária em cromatografia: uma proposta de aula experimental nos cursos de graduação

This article describes an experiment that involves the extraction and separation of the pigments of spinach extract by column chromatography using the silica obtained from rice husk ash as a stationary phase. The experimental procedure is very simple to apply in the chemistry laboratory, and allowed to illustrate some concepts of organic chemistry: structure of organic molecules, solubility, polarity, extraction, partition coefficient, adsorption and retention factor (Rf), as well as objectives and fundamentals of chromatographic methods. The experiment can be carried out in a 4 h period.

Organic Chemistry YouTube Writing Assignment for Large Lecture Classes

This work describes efforts to incorporate and evaluate the use of a YouTube writing assignment in large lecture classes to personalize learning and improve conceptual understanding of chemistry through peer- and self-explanation strategies. Although writing assignments can be a method to incorporate peer- and self-explanation strategies, this method is not often incorporated in large lecture classes and lower-division science courses. This work primarily focuses on a YouTube script writing assignment where a student selects an organic chemistry concept and describes how they would teach or creatively explain the concept to their fellow classmates using real-world examples in a popular YouTube video format. In a more elaborate version of the assignment, students then proceed to make a YouTube video based on this written assignment. Subsequent details and feedback about the assignment are also presented.

Chemistry Students and Human Rights

Chemistry Students and Human Rights

ChemInform Abstract: The Principle of Nonperfect Synchronization: Recent Developments

AbstractReview: 212 refs.