Hello everyone Welcome the tutorial on Formation of molecules in GChemPaint. In this tutorial, we will learn to * Add and modify structure of compounds * Change current element * Add Alkyl groups * Add and modify carbon chain Here I am using Ubuntu Linux OS version. 12.04 GChemPaint version 0.12.10 To follow this tutorial you should be familiar with, GChemPaint chemical structure editor. If not, for relevant tutorials, please visit our website. Here is slide for the structures of Propane, Butane and Heptane. I have opened a new GChemPaint application with Propane and Butane structures as shown in the slide. Let’s replace the terminal Carbon atoms in Butane structure with Chlorine atoms. For this I will use Periodic table combo button. Click on the Current element drop-down arrow button. This button is known as Periodic table combo button. Observe the built-in Modern periodic table. Click on Cl from the table. Observe Cl in the tool box. Click on Add or modify an atom tool. Click on the terminal atoms to replace them with Clorine (Cl) atoms. The new structure obtained is 1,2-Dichloroethane. Let’s write its name below the structure. Click on Add or modify a text tool. Text tool’s property page opens. Click on the Display area below the structure. You can see the blinking cursor enclosed in a green box. Type 1,2-Dichloroethane in the box . Click on Select one or more objects tool, to close the text tool’s property page. Next let’s replace the central Carbon atom in Propane structure with Oxygen atom. Place the cursor near the central atom of Propane structure. Press capital O. A Sub-menu with O and Os opens. Select O. Carbon and Hydrogen atoms will be replaced by Oxygen atom. The new structure obtained is Dimethylether. Let’s write its name below the structure. Click on Add or modify a text tool. Click on the Display area below the structure. Type Dimethylether in the box. Let’s save the file now. Click on Save the current file icon on the toolbar Save as dialog box opens. Enter the file name as Chloroethane-ether. Click on Save button. Let’s Click on Close button to close the window. Here is an assignment Draw ‘Ethane and Pentane structures. Replace one Carbon atom of Ethane with Br. Replace the terminal Carbon atoms of Pentane with I. Your completed assignment should look like this. Now I will explain about Alkyl groups. Alkyl group is a fragment of Alkane. For example: Methyl CH3 is a fragment of Methane CH4 Successive members of an Alkyl group differ by a CH2 group. Homologues of the Alkyl group series include, Methyl CH3 Ethyl C2H5 Propyl C3H7 Butyl C4H9 and so on. I have opened a new GChemPaint application with Heptane structure. Now I will demonstrate how to number the carbon chain positions. Numbering helps to identify the chain positions. Click on Add or modify a text tool. Click on the Display area near the first chain position. Enter 1 in the green box. Next, click near the second chain position. Enter 2 in the box. Likewise I will number the other chain positions as 3, 4, 5, 6 and 7. Now let’s branch Heptane using Alkyl groups at various positions. Let us add a Methyl group to the third position. Click on Add a bond or change the multiplicity of existing one tool. Click on the position. Observe the change in the atoms. Let us add an Ethyl group on the fifth position. Click on Add a chain tool. Click on the position. Next I will display atoms on all positions. Right-click on the position. A Submenu opens Select Atom and then click on Display symbol. Likewise I will display atoms at other positions. Let’s see how many times we can branch at one position. Click on Add a bond or change the multiplicity of existing one tool. Click on the fourth position. Click again. Observe the branching in the Carbon chain. Try to click for the third time. We do not see the branching. Note that branching is possible only twice at each position. This is because it satisfies Carbon’s tetra valency. To save the file, Press CTRL+ S. Save as dialog box, opens. Enter the file name as Alkyl Groups. Click on Save button. Let’s Summarize what we have learnt. In this tutorial we have learnt to, * Add and modify structure of compounds * Change current element * Add Alkyl groups * Add and modify carbon chain As an assignment, Draw Octane structure . Add Propyl and Butyl groups at the fourth and fifth positions of the chain. Your completed assignment should look like this. Watch the video available at this URL http://spoken-tutorial.org/What_is_a_Spoken_Tutorial It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it The Spoken Tutorial Project Team Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, please write to [email protected] 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 http://spoken-tutorial.org/NMEICT-Intro This brings us to the end of this tutorial. Animation is done by Udhaya Chandrika. This is Madhuri Ganpathi from IIT Bombay signing off. Thank you for joining.