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

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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.
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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