Alicyclics & Aromatics

Cyclic hydrocarbons, or alicyclics are ring-shaped structures that can act as either a parent chain of a side group.

• general formula = CNH2N
• more reactive as opposed to straight-chains
• numbering can start anywhere on the ring, but the #'s of the side chains must be the lowest possible numbers
• prefix "cyclo-" is added to the beginning of the parent chain

Naming

Cycloalkanes

1. count length of carbon chain
2. similar naming rules as straight-chains
3. if the numbers of the side groups are equal (ex. 2,4,6 either way you count) then you give the lower number to the side group that comes first in the alphabet

Cycloalkenes & Cycloalkynes

1. similar naming to cycloalkanes, except with different endings
2. more reactive than cycloalkanes
3. when numbering the double/triple bonds, they should always be located at the first and second carbons

Aromatics

Properties

• electrons are "delocalized" meaning they can move around the ring and are shared equally in the ring
• carbon-carbon bonds have same reactivity because of delocalization
• less reactive structures than cycloalkanes
• have a nice odour
• contains atleast one benzene ring

Naming

• can be a parent or side chain
• as a side chain, its given the name "phenyl"
• as a parent chain, "benzene" is added to the end of the whole name

Ex. Name the structures:
                                                 
                                                              cyclopentyne


                                       
                                                       4-chlorocyclohexene


All this organic chemistry is tough! It's a lot to memorize and there are a lot of rules to follow. But rest assured, it gets easier. Try these exercises. After all, practice makes perfect right? :)







                              

                                                     

Halides & Nitro Compounds

Hydrocarbons (molecules composed of hydrogen and carbon atoms) are the foundation of organic chemistry. They are the base of a organic structure, and we can add side groups to the base! Kind of like a tree! The hydrocarbon chain of the molecule is the roots and the trunk of a tree, and the side groups are the branches! Let's look at some possible "branches":

Halides

Properties

1. Insoluble in water
2. Compounds that contain Iodine are really reactive
3. Compounds that contain Chlorine or Bromine are reactive under certain conditions

List of Halogens

Br = Bromo
Cl = Chloro
F = Fluoro
I = Iodo

**When the molecule contains more than one halogen, we use the suffixes (di-, tri-, tetra-, penta-) to represent it. The suffix goes before the halogen (ex. tetrabromo; diiodo)


Nitros

Properties

1. Usually insoluble in water
2. mostly nreactive unless put under certain conditions
3. have a generally nice odour
4. Likely to be explosive (ex. trinitrotoluene, or TNT)

Nitro
NO2 = Nitro


Naming

Naming of these structures is similar to that of hydrocarbons. You simple count the smallest # of carbon atoms until you reach the halide or nitro and the # goes before the name.

• side groups go before the parent chain
• side groups go in alphabetical order

Ex. Name the structure
                                                  
                                                             2-bromopentane

1. Count the longest chain of carbon atoms, in this case 5, or pentane *each point you see in the picture represents a carbon atom*
2. Count the smallest # of carbon atoms until you hit bromine, in this case, it's 2!

                        

Amines

Amines serve many purposes and like all functional groups, are used a lot in our society.  They are used in medicine, the textile industry, as flotation agents and stabilizers, to name a few. 

Amines have fairly high boiling points and produce fishy smells. 

Amines are based on the structure of Ammonia.  NH3.  Nitrogen has 5 electrons, are so it will bond with 3 other electrons to try and become stable.  There are three types of amines.  Primary, secondary, and tertiary.  In primary bonds, a Nitrogen bonds with 1 Carbon and 2 Hydrongens.  In secondary, Nitrogen bonds with 2 Carbons and 1 Hydrogen. And you guessed it, in tertiary, Nitrogen bonds with 3 Carbons.

General Structure:

The 'H's don't necessarily have to be Hydrogens.  They can also be Carbon chains. Amines, like ethers, are side groups.

Naming Rules

1) Identify the longest Carbon chain and name it. 

2) Where the Nitrogen branches off is the start of the side group.  Count the number of Carbons attatched to this.  Name it with amino(primary amine) before the parent chain. 

3) If the Amine group is not located on the first Carbon, identify the location.

Let's do an example. 

The longest chain is pentane, so that is the ending of your name.  The lowest number your amine group can be on is 2.  Thus 2-aminopentane.

Note: nitro group are NO2.  Amines are NH2. 

And here's a wonderful song to help you study for a test or distinguish the different functional groups.

It's a Chemistry Thing Song

Here's a good site if you need more help.

Review

Khan Academy also has many great videos.

Alkenes & Alkynes

Alkenes and Alkynes

Alkenes and alkynes are similar words...2 words off by a factor of one letter. Now they may seem similar, but are they in fact similar? Yes they are! Similarly to their names, their bonds are off by a factor of one; alkenes are double bonds, and alkynes are triple bonds. And they are also really similar to alkanes. Think of them as the three stooges.. or the three amigos! Whatever you choose to relate them to, just remember, alkanes -1 bond, alkenes – double bond, alkynes – triple bond.

Naming
   
    Alkenes

• General formula = CNH2N
• Naming is similar to alkanes
• Double bond placement is at lowest possible # and placed in front of parent name
• Find longest chain of carbon atoms and change the ending from the prefix –ane to –ene (ex. butane is changed to butene)
• Count the # of carbon atoms until you reach the double bond. Count from both sides of the chain to see which has the smallest #
• Write #’s of side groups and their names. **Side groups should be in alphabetical order!!**

Ex. Name this structure

             

                                        

                                                                         2-pentene

1. Count the longest chain of carbon atoms. In this case, it's 5, which is where we get the pentene.  
2. Count to see on which carbon atom the double bond is placed. So it's either on the 3rd or 2nd carbon atom, but we want the smallest #, so we'll go with the 2nd.

Sometimes, with double bonds you will get structures that are the same but have different geometry. These structures are called geometric isomers:

                               
                                          trans-2-butene                      cis-2-butene
   
In the example above, we have 2-butene. As you can see, they have the same structure, just the placement of the atoms is different.To distinguish the 2, we use "cis" and "trans".

• "cis" is used when the carbon atoms are above/below the double bonded centre of the structure
• "trans" is used when the carbon atoms go in a diagonal

When naming, add the "cis" or "trans" (which ever applies to the situation) to  the beginning of the name.


   Alkynes

• General formula = CNH2N - 2
• Ending changed from prefix -ane to -yne (ex. nonane is changed to nonyne)
• Double/triple bond placement is at lowest possible # and placed in front of parent name
• Count the # of carbon atoms until you reach the double bond. Count from both sides of the chain to see which has the smallest #
• Write #’s of side groups and their names. **Side groups should be in alphabetical order!!**

Ex. name the structure

                                   
                                                              heptyne

1. Count the longest chain of carbon atoms. In this case, 7, which gives us heptyne.
2. The smallest # of the placement of the triple bond is 1, but we don't need to write the 1 out, it is assumed it's 1 if there's no # before it

And that's it for alkenes and alkynes! Hopefully you understood and it wasn't too hard. Organic chemistry is confusing, but it just takes time and practice to get used to it.



 Extra help!

http://www.youtube.com/watch?v=6NygjuEFkIc

http://www.youtube.com/watch?v=oYoQpDtBLac