GChemPaint/C3/Aromatic-Molecular-Structures/English-timed

Title of the tutorial: Aromatic-Molecular-Structures

Author: Madhuri Ganapathi

Key words: Add a six membered cycle, Add a four membered cycle, Add a bond or change the multiplicity of the existing one, Add or modify a group of atoms, Eraser, Merge two molecules, Display symbol, Benzene, fluoro(F), methyl(CH3), nitro(NO2), hydroxy(OH), carboxy, Video tutorial.

Time	Narration
00:01	Hello everyone.
00:02	Welcome to this tutorial on Aromatic Molecular Structures in GChemPaint.
00:07	In this tutorial, we will learn to:
00:10	* Convert Cyclohexane to Cyclohexene
00:13	* Convert Cyclohexene to Benzene
00:16	* Substitute Hydrogen of Benzene ring with other atoms.
00:20	* Substitute Hydrogen of Benzene ring with group of atoms
00:24	* Merge two molecules.
00:26	Here I am using
00:28	Ubuntu Linux OS version 12.04,
00:32	GChemPaint version 0.12.10.
00:37	To follow this tutorial, you should be familiar with
00:41	GChemPaint chemical structure editor.
00:44	If not, for relevant tutorials, please visit our website.
00:50	I have opened a new GChemPaint application.
00:54	Let us first add a six membered cycle to the Display area.
00:59	Click on Add a six membered cycle tool.
01:02	Click on the Display area.
01:04	Click on Add a bond or change the multiplicity of the existing one tool.
01:10	Add two bonds on every corner of the cycle.
01:14	Position the bonds in such a way that no two bonds touch each other.
01:19	To do so, click and drag the bonds to proper positions.
01:24	Let us display Carbon atoms on all the corners of the cycle.
01:28	Right click on any one of the corner.
01:31	A sub-menu appears.
01:33	Select Atom and then click on Display symbol.
01:36	Likewise, add Carbon atoms on all corners of the cycle.
01:42	To add Hydrogen atoms to the bonds, press H on the keyboard.
01:47	Click on Add or modify an atom tool.
01:51	Click on all the bond positions.
01:54	Again, see to it that no two Hydrogens overlap each other.
01:59	The obtained structure is (C6H12) Cyclohexane.
02:04	Let's copy and paste the structure.
02:07	Press Ctrl+A to select the structure.
02:10	Press Ctrl+C to copy and Ctrl+V to paste the structure.
02:15	Let us convert the second Cyclohexane structure to Cyclohexene.
02:19	Click on the Eraser tool.
02:22	Delete one Hydrogen bond from each of the adjacent carbon atoms.
02:27	Click on Add a bond or change the multiplicity of the existing one tool.
02:33	Then click on the bond between deleted Hydrogen bonds.
02:37	A double bond is formed.
02:40	The obtained structure is Cyclohexene(C6H10)
02:44	Let us convert Cyclohexene to Cyclohexadiene and then to Benzene.
02:51	Ensure that Current element is Carbon.
02:56	Click on the Eraser tool.
02:58	Delete one Hydrogen bond from each of the adjacent Carbon atoms.
03:03	Click on Add a bond or change the multiplicity of the existing one tool.
03:09	Then click on the bond between deleted Hydrogen bonds.
03:13	A second double bond is formed.
03:16	The obtained structure is Cyclohexadiene(C6H8).
03:22	Likewise let's repeat the process to form the third double bond.
03:28	The obtained structure is Benzene(C6H6)
03:33	As an assignment,
03:35	draw the structures of: * Cyclobutane and convert to Cyclobutadiene
03:39	* Cyclopentane and convert to Cyclopentadiene
03:45	Your completed assignment should look like this.
03:49	Next let us learn about Benzene derivatives.
03:53	Functional groups can substitute Hydrogens in Benzene, to derive various chemical compounds
03:59	Functional groups that substitute Hydrogen are
04:02	fluoro(F),
04:03	methyl(CH3),
04:04	nitro(NO2),
04:05	hydroxy(OH) and
04:06	others.
04:08	Let us copy and paste the Benzene structure twice, on the Display area.
04:13	Click on Select one or more objects tool to select the Benzene structure.
04:18	Press Ctrl+C to copy and press Ctrl+V twice to paste the structures.
04:24	Let's Substitute Hydrogen of the first Benzene structure with a Fluorine atom.
04:30	Press F on the keyboard.
04:32	Click on Add or modify an atom tool.
04:35	Click on Hydrogen to substitute it with Fluorine.
04:40	The obtained structure is Fluorobenzene.
04:44	Next let's substitute the Hydrogen of the second Benzene with a group of atoms.
04:50	Click on Add or modify a group of atoms tool.
04:54	Click on any one of the Hydrogens.
04:57	Observe that Hydrogen is enclosed in a green box with a blinking cursor.
05:03	Let's substitute Hydrogen with a methyl group.
05:06	Remove Hydrogen and type capital C H and 3
05:12	Click anywhere on the Display area.
05:15	The obtained structure is Methyl benzene.
05:19	Let's substitute Hydrogen of the third Benzene with a nitro group.
05:24	Click on any one of the Hydrogens.
05:27	Remove Hydrogen and type capital N O 2
05:32	The obtained structure is Nitrobenzene.
05:36	Let's see Carbon positions in the Benzene ring.
05:40	Six Carbon atoms are numbered from 1 to 6 in Benzene.
05:45	All six positions are equivalent, before Hydrogen is substituted.
05:51	Electron density of the ring changes, when Hydrogen is substituted by a functional group.
05:57	Electron density is dependent on the Substituent.
06:01	A mono-substituted compound of Benzene can be substituted at positions:
06:06	* 1 and 4- as Para.
06:09	* 2 and 6- as Ortho.
06:12	* 3 and 5- as Meta.
06:15	Now let's substitute Methylbenzene structure with another methyl group.
06:20	Click on Add or modify a group of atoms tool.
06:24	Click on the second Hydrogen position of the ring.
06:28	To substitute Hydrogen in the green box with methyl group,
06:32	type capital C H 3.
06:35	The new structure obtained is ortho-Xylene.
06:39	Let's substitute Nitrobenzene with a Carboxy group.
06:44	Click on the fourth Hydrogen position of the ring.
06:48	To substitute Hydrogen in the green box with Carboxy group,
06:52	type capital C O O H
06:57	The new structure obtained is para-Nitrobenzoic acid.
07:02	Press Ctrl+Z to undo the process.
07:05	Substitute third Hydrogen position of Nitrobenzene with a nitro group.
07:11	Remove Hydrogen and type capital N O 2
07:17	The new structure obtained is meta-Dinitrobenzene.
07:22	Here is an assignment.
07:24	Draw seven Benzene structures.
07:25	Substitute one of the Hydrogens of:
07:28	First Benzene with bromo.
07:30	Second Benzene with iodo.
07:32	Third Benzene with hydroxy.
07:34	Fourth Benzene with amino.
07:36	Fifth Benzene with ethyl.
07:39	Also substitute: * Two of the Hydrogens of the sixth Benzene with Chlorine atoms.
07:44	* First and fourth Hydrogen positions of the seventh Benzene with Carboxy groups.
07:51	Your completed assignment should look like this.
07:55	Now, let's learn to merge two structures.
07:57	Let's open a new window.
08:00	Ensure that current element is Carbon.
08:04	Click on the Add a four membered cycle tool.
08:07	Click on the Display area twice.
08:10	Click on Select one or more objects tool.
08:14	Click on the second structure.
08:16	Drag it and place it close to the first structure
08:20	such that they touch each other.
08:23	Press Ctrl+A to select the structures.
08:26	Merge two molecules tool becomes active.
08:30	Click on Merge two molecules tool, to merge the molecules.
08:34	Drag the structures to observe merging.
08:38	Let's summarize what we have learnt.
08:41	In this tutorial, we have learnt to:
08:43	* Convert Cyclohexane to Cyclohexene
08:46	* Convert Cyclohexene to Benzene
08:49	* Substitute Hydrogen of Benzene with fluoro, methyl, nitro and carboxy groups.
08:55	* Merge two four membered cycles.
08:58	Here is an assignment:
09:00	* Merge Two Benzene molecules
09:02	* Two Pentane structures
09:04	* Cyclopentane and Cyclohexane molecules.
09:08	Your completed assignment should look like this.
09:12	Watch the video available at this link.
09:15	It summarizes the Spoken Tutorial project.
09:19	If you do not have good bandwidth, you can download and watch it.
09:23	The Spoken Tutorial Project Team: Conducts workshops using spoken tutorials.
09:27	Gives certificates to those who pass an on-line test.
09:31	For more details, please write to contact@spoken-tutorial.org.
09:37	Spoken Tutorial Project is a part of the Talk to a Teacher project .
09:41	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
09:48	More information on this Mission is available at this link .
09:53	This is Madhuri Ganapathi from IIT Bombay signing off.
09:57	Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14