Difference between revisions of "GChemPaint/C3/Resonance-Structures/English"
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Author: '''Madhuri Ganapathi''' | Author: '''Madhuri Ganapathi''' | ||
| − | Key words: ''' | + | Key words: '''Show Electron shift and Resonance Structures, Create a reaction pathway, Create a mesomeric pathway, Build Retrosynthetic Pathway, Video tutorial'''. |
Revision as of 12:05, 28 April 2014
Title of the tutorial: Resonance Structures
Author: Madhuri Ganapathi
Key words: Show Electron shift and Resonance Structures, Create a reaction pathway, Create a mesomeric pathway, Build Retrosynthetic Pathway, Video tutorial.
| Visual Cue | Narration
|
|---|---|
| Slide Number 1
Title Slide |
Hello everyone.
Welcome to this tutorial on Resonance Structures in GChemPaint. |
| Slide Number 2
Learning Objectives |
In this tutorial, we will learn to,
|
| Slide Number 3
System Requirement |
For this tutorial I am using
Ubuntu Linux OS version 12.04. GChemPaint version 0.12.10. |
| Slide Number 4
Pre-requisites |
To follow this tutorial you should be familiar with GChemPaint.
If not, for relevant tutorials, please visit our website. |
| Switch to GChemPaint window. | I will switch to GChemPaint window.
Here you can see EthylChloride and Methylbromide structures. |
| I will show how to obtain a Carbo-cation. | |
| Point to Chlorine atom. | Let's add a pair of electrons on the Chlorine atom of EthylChloride. |
| Click on Add an electron pair tool>>Click on Chlorine atom. | Click on Add an electron pair tool.
Click on Chlorine atom and observe what happens. |
| Next, I will show an electron pair shift in the Carbon-Chlorine bond. | |
| Click on Add a curved arrow to represent an electron pair move.
Point to the window. |
Click on Add a curved arrow to represent an electron pair move.
Property window opens. |
| Click on End arrow at center of new bond check box. | Click on End arrow at center of new bond check box. |
| Click on Carbon-Chlorine bond. | Click on Carbon-Chlorine bond.
It moves the electron pair to the correct position. |
| Point to the shift. | Place the cursor on the curved arrow and observe the electron shift. |
| Point to the structure. | I will the copy of the structure. |
| Click on Add on arrow >>click between the structures. | Now, click on Add on arrow and click between the structures. |
| Formation of a Carbo-cation is initialized by a base like Sodium Hydroxide(NaOH). | |
| Click on Add or modify a group of atoms tool >> click above the arrow. | Click on Add or modify a group of atoms tool and click above the arrow. |
| Type NaOH in the green box. | Type NaOH in the green box. |
| Click on Selection tool>>Click on the text Base to select>>Right-click click on the arrow. | Click on Selection tool and select NaOH.
Then, right-click on the arrow. |
| Point to the submenu.
Select Arrow >>click on Attach selection to arrow. |
In the submenu, select Arrow.
Click on Attach selection to arrow. |
| Point to the dialogue box. |
A dialogue box with heading Arrow associated appears. |
| Point to drop down. | In Role drop-down, select “Reactant” and click on Close. <PAUSE> |
| Now, let's convert second EthylChloride to Ethyl Carbo-cation and Chloride ions. | |
| Click on Eraser tool and click on Carbon-chlorine bond.
Point to products. |
Click on Eraser tool and click on Carbon-chlorine bond.
Ethane(CH3-CH3) and HCl are formed. |
| Point to the central carbon. | When electrons shift from Carbon to Chlorine, Carbon gains a positive charge. |
| Click on Increment the charge tool>>Click at the position from where Carbon-chlorine bond to deleted. | Click on Increment the charge tool.
Click at the position from where Carbon-chlorine bond was deleted. Ethyl Carbo-cation(CH3-CH2+) is formed. |
| Click on Decrement the charge tool>>click on HCl. | To form Chloride ion, click on Decrement the charge tool.
Click on HCl. Chloride(Cl-) ion is formed. <PAUSE> |
| Now let's move to single electron shift. | |
| Point to Methylbromide. | Let's use the Methylbromide structure to obtain free radicals. |
| Click on Add a curved arrow to represent a single electron move tool. | Click on Add a curved arrow to represent a single electron move tool. |
| Click twice on Bromo-methane bond. | Click on Methylbromide bond to obtain a curved arrow.
Shift the Pencil tool a little on the bond, click again to get second curved arrow. |
| Point to the Bromo-methane and curved arrows. | One curved arrow moves to bromo(Br) and other moves towards methyl(CH3).
Both Bromo(Br) and methyl(CH3) will get one electron each from the bonded pair. |
| Point to the arrow. | To show the products, let's add an arrow.
Click on Add an arrow, click on Display area. |
| Point to the free radicals. | Formation of free radicals involves heat in the reaction. |
| Click on Add or modify a text tool.
Click on the Display area above the arrow. Type “Heat” in the green box. |
Click on Add or modify a text tool.
Click on Display area above the arrow. Type “Heat” in the green box. |
| Click on Selection tool>>select “Heat”. | Click on Selection tool and select “Heat” |
| Right-click on the arrow.
Point to the submenu>> Select Arrow >>click on Attach selection to arrow. |
Right-click on the arrow.
In the Submenu select Arrow. Click on Attach selection to arrow. |
| Point to the dialogue box. |
A dialogue box with heading Arrow associated appears. |
| Point to drop down. | Notice that Role drop down list has more options. |
| Point to Role drop down.
Select “Temperature”>>Click on Close. |
In the Role drop-down, select “Temperature” and click on Close. |
| Point to the structure. | I will copy the structure. |
| Now let's create the free radicals. | |
| Click on Eraser tool and click on Carbon-bromine bond.
Point to CH4 and HBr. |
Click on Eraser tool and click on Carbon-bromine bond.
Methane(CH4) and Hydrogen-bromide(HBr) are formed. |
| Click on Add an upaired electron tool.
Click on CH4 and HBr. |
Click on Add an upaired electron tool.
Click on Methane(CH4) and Hydrogen-bromide(HBr) Methyl(CH3) and Bromium(Br) free radicals are formed. |
| Let's create a reaction pathway. | |
| Click on Selection tool.
Drag the cursor over the reaction to select it. |
Click on Selection tool.
To create a reaction pathway, first select the complete reaction. |
| Right-click on the selection.
Point to the Submenu. |
Now, right-click on the selection.
A submenu opens. |
| Click on Create a new reaction.
Point to the previous reaction |
Click on Create a new reaction.
Reaction path is created. Drag to see the reaction pathway. Likewise, I will create the reaction pathway for the previous reaction. |
| Right-click on the selection again.
Click on Destroy the reaction. |
We can also remove the reaction pathway, if we want to.
To do so, right-click on the reaction again and click on Destroy the reaction. |
| Point to the reactants and products.
Drag any object. |
This action will remove the reaction pathway.
Drag any of the objects, and you will see that they can be moved individually. |
| Now we move on to Resonance or mesomery using double headed arrow. | |
| Switch to GChempaint.
Point to the structure(CH3-NH2). |
I have opened a new GChemPaint window with structures of Nitromethane. |
| Point to the structures | I had added curved arrows and charges to show electron shifts within the structures. |
| Now let's add a double headed arrow. | |
| Click on Add a double headed arrow.
Click on Display area beside Nitromethane. |
Click on Add a double headed arrow.
Click on Display area in between Nitromethanes. |
| Point to the structures | The two structures are canonical forms of Nitromethane. |
| Press CTRL+A to select the structures.
Right-click on the selection. Point to the Submenu. |
Press CTRL+A to select the structures.
Right-click on the selection. A submenu opens. |
| Click on Create a new mesomery relationship | Click on Create a new mesomery relationship.
Drag to see the relationship. |
| Slide Number
Resonance structures of Benzene |
Here is slide for resonance structures of Benzene. |
| Now, let's learn to create a retro-synthetic pathway. | |
| Point to the window. | I have opened a new GChemPaint window with the required structures. |
| Point to the final product intermediates and starting material. | Retrosynthetic pathway
starts with the product and goes to the reactant along with all the intermediates. |
| Point to the structures | In this pathway, the final product is Orthonitrophenol and the starting material is Benzene. |
|
Let's add a retro-synthetic arrow, to show the retro-synthetic pathway. | |
| Click on Add arrow for a retrosynthetic step >> Click in between all the compounds. | Click on Add arrow for a retrosynthetic step.
Click in between all the compounds. |
| Press CTRL+A select all structures.
Right click on the selection. |
Press CTRL+A select all structures.
Right click on the selection. |
| Point to Submenu.
Click on Create a new retrosynthesis pathway. |
A sub-menu opens.
Click on Create a new retrosynthesis pathway. Drag to see the created pathway. |
| Let's summarize what we have learnt. | |
| Slide Number 9
Summary |
In this tutorial we have learnt to
Show electron shifts using curved arrows Attach reaction conditions to reaction arrows. Create and destroy reaction pathway using a reaction arrow Create a new mesomery relationship using double headed arrow Create a retro-synthetic pathway using the retro-synthetic arrow. |
| Slide Number 10
Assignment |
As an assignment
Using arrow properties 1. Create a reaction pathway for the reaction between Bromo-Ethane (C2H5Br) and Sodium(Na) with Dry ether as a solvent to obtain Butane(C4H10) and Sodium bromide(NaBr). 2. Add stoichiometric coefficients to the reactants and products. 3. Draw resonance structures of Naphtalene, Anthracene and Carbondioxide |
| Point to the reaction pathway.
Point to the resonance structures |
This is the required reaction pathway. These are the resonance structures of Napthalein, Anthracene and Carbondioxide. |
| Slide Number 10
Acknowledgement |
Watch the video available at this URL.
http://spoken-tutorial.org/What_is_a_Spoken_ Tutorial It summarizes the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it |
| Slide Number 11 | The Spoken Tutorial Project Team:
Conducts workshops using spoken tutorials Gives certificates to those who pass an on-line test For more details, please write to contact@spoken-tutorial.org |
| Slide number 12 | Spoken Tutorial Project is a part of the Talk to a Teacher project
It is supported by the National Mission on Education through ICT, MHRD, Government of India More information on this Mission is available at this link |
| This is Madhuri Ganapathi from IIT Bombay signing off. Thank you for joining. |
