<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0187-893X</journal-id>
<journal-title><![CDATA[Educación química]]></journal-title>
<abbrev-journal-title><![CDATA[Educ. quím]]></abbrev-journal-title>
<issn>0187-893X</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Facultad de Química]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0187-893X2016000400269</article-id>
<article-id pub-id-type="doi">10.1016/j.eq.2016.02.003</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Modified Newman projections: A new representation of the Newman notations to convey conformational properties]]></article-title>
<article-title xml:lang="es"><![CDATA[Una nueva representación de la notación de Newman para visualizar las propiedades conformacionales]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Khalilian]]></surname>
<given-names><![CDATA[M. Hossein]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Khosravi]]></surname>
<given-names><![CDATA[Hormoz]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Mirzaei]]></surname>
<given-names><![CDATA[Saber]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Razi University Faculty of Chemistry ]]></institution>
<addr-line><![CDATA[Kermanshah ]]></addr-line>
<country>Iran</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>10</month>
<year>2016</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>10</month>
<year>2016</year>
</pub-date>
<volume>27</volume>
<numero>4</numero>
<fpage>269</fpage>
<lpage>277</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0187-893X2016000400269&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0187-893X2016000400269&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0187-893X2016000400269&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Conformational analysis is one of the significant subjects in the organic chemistry curriculum. Since this subject may be intricate for some beginner students, a concrete model (an activity) has been devised to explain the conformational concepts with an intriguing and simple method. This model is based on geometric shapes (particularly triangles) in which the revolution of each shape on its axis at the centroid (around its vertices and edges) simulates the rotation about a single bond in a molecule. If we take edges as lower energy (more stable) and vertices as higher energy (less stable), this revolution gives a graph almost identical to the actual conformational energy diagram of that molecule. These shapes can also incorporate into the Newman projections to form a tangible representation of these notations. Most of the participants, who got familiar with these newly modified Newman projections, found them beneficial in enhancing the students&#8217; perception of the basic conformational properties of the molecules. Furthermore, searching for a relevant shape to match the right molecule serves as an activity that in addition to being enjoyable can encourage the students to get engaged with the topic. This model is applicable to a large variety of molecules such as the hydrocarbon, aldehyde and ketone molecules, which can also generalize to more functional groups and compounds.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[El análisis conformacional es uno de los temas más significativos en la enseñanza de química orgánica. Puesto que este tema puede ser complicado para algunos estudiantes, se propone un modelo concreto (una actividad) con vista a mejorar la percepción para explicar los conceptos conformacionales con un método sencillo y fascinante. Este modelo se basa en formas geométricas (triángulos) en las que el giro de cada triángulo alrededor de su eje (alrededor de sus vértices y bordes) simulará la rotación de la molécula entorno a un enlace sencillo. Si consideramos los bordes y vértices como de baja energía (más estable) y de alta energía (menos estable) respectivamente, el giro dará una gráfica semejante al diagrama de energía conformacional real de la molécula. Además, esta forma geométrica se puede incorporar a las proyecciones de Newman a fin de tener una representación tangible de esta notación. La mayoría de los participantes, que se familiarizaron con esta nueva proyección de Newman modificada, encontraron beneficios en la percepción de los estudiantes sobre las propiedades conformacionales básicas de las moléculas. Asimismo, la búsqueda de una forma geométrica conveniente que corresponda a una determinada molécula sirve como una actividad agradable la cual puede atraer a los estudiantes al tema. Este modelo se aplica a una gran variedad de moléculas incluyendo hidrocarburos, aldehídos y cetonas, y puede generalizarse a otros grupos funcionales y moléculas.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Demonstration]]></kwd>
<kwd lng="en"><![CDATA[Organic chemistry]]></kwd>
<kwd lng="en"><![CDATA[Newman projections]]></kwd>
<kwd lng="en"><![CDATA[Conformational analysis]]></kwd>
<kwd lng="es"><![CDATA[Demostración]]></kwd>
<kwd lng="es"><![CDATA[Química orgánica]]></kwd>
<kwd lng="es"><![CDATA[Proyección de Newman]]></kwd>
<kwd lng="es"><![CDATA[Análisis conformacional]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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