Organic Chemistry Last unit for the year.

What does Organic mean? The word Organic – –in Biology it means any thing that is living or has lived. The opposite is Non-Organic. –in Chemistry, an Organic compound is one containing Carbon atoms. The opposite term is Inorganic.

Inorganic All substances are made up of molecules which are collections of atoms. We have spent the year studying simple Inorganic molecules containing only a few atoms. – For example, a water molecule is composed of two atoms of Hydrogen and one atom of Oxygen. We write its formula as H 2 O.

Carbon By far and away the best atom for making large molecules with is Carbon. Carbon can make molecules that have tens, hundreds, thousands even millions of atoms! The huge number of possible combinations means that there are more Carbon compounds than those of all the other elements put together!

A single Carbon atom is capable of combining with up to four other atoms. The Carbon atom is one of the few that will combine with itself. This means that Carbon atoms can form chains and rings onto which other atoms can be attached. This leads to a huge number of different compounds. All organic chemistry is based upon unique properties of the carbon atom.

Carbon Atom Carbon, C, hybridization to 3 sp 3 orbitals, carbon can now form 4 bonds, may be single, or in combination of double (sp 2 ) or triple bonds (sp). Carbon forms very strong bonds with many non-metal atoms, H, O, Cl, N. –Note: silicon and germanium are in the same family and form 4 bonds, but the bond energy is low, so weak bonds are formed. This severely restricts their chemistry.

Hydrocarbons Carbon compounds are classified according to how the Carbon atoms are arranged and what other groups of atoms are attached. The simplest Organic compounds are made up of only Carbon and Hydrogen atoms only. Even these run into thousands! Compounds of Carbon and Hydrogen only are called Hydrocarbons.

Saturated Hydrocarbon - only C-H and single C-C Unsaturated Hydrocarbon - one or more multiple C-C

1. Straight chain: The carbons are bonded to no more than two other carbons. 2. Branched chain: At least one carbon is bonded to more than two other carbons. The branches are referred to as substituent groups. 3. Cyclic: All of the carbons are bonded to two other carbons. Aromatic compounds are a special class of cyclic hydrocarbons.

Types of Hydrocarbons A. alkanes - comprised of all single bonds C n H 2n+2 B. alkenes - comprised of at least one double bond C n H 2n C. alkynes - comprised of at least one triple bond C n H 2n-2

Structural vs Condensed  Structural formulas show all the atoms and bonds in the molecule.  Condensed structural formulas show the number of hydrogens around each carbon. CH 3

Structural Formulas “Lazy” way to write the Hydrogens Instead of drawing the bonds, just state how many hydrogens are attached NOTE: The bonds are between CARBONS in a parent chain, and not hydrogens! Structural Formula Lewis Structure

Alkanes Hydrocarbon chains where all the bonds between carbons are SINGLE bondsHydrocarbon chains where all the bonds between carbons are SINGLE bonds Name uses the ending –aneName uses the ending –ane Examples: Methane, Propane, Butane, Octane, 2-methylpentaneExamples: Methane, Propane, Butane, Octane, 2-methylpentane

Prefixes for # of Carbons 1Meth6Hex 2Eth7Hept 3Prop8Oct 4But9Non 5Pent10Dec

Prefix-Parent-SUFFIX RootNumber of Carbons Meth1 Eth2 Prop3 But4 Pent5 Hex6 Hept7 Oct8 Non9 Dec10 Functional GroupEnding Alkaneane Alkeneene Alkyneyne Alcoholol Ketoneone Aldehydeal Carboxylic acidoic acid Esteroate Amideamide

Summary: IUPAC Rules for Alkane Nomenclature 1. Find and name the longest continuous carbon chain. This is called the parent chain. (Examples: methane, propane, etc.) 2. Number the chain consecutively, starting at the end nearest an attached group (substituent). 2. Number the chain consecutively, starting at the end nearest an attached group (substituent). 3. Identify and name groups attached to this chain. (Examples: methyl-, bromo-, etc.) 3. Identify and name groups attached to this chain. (Examples: methyl-, bromo-, etc.) 4. Designate the location of each substituent group with the number of the carbon parent chain on which the group is attached. Place a dash between numbers and letters. The prefixes di-, tri-, etc. are used to indicate multiple identical substituents. (Example: 3-chloropentane) 4. Designate the location of each substituent group with the number of the carbon parent chain on which the group is attached. Place a dash between numbers and letters. The prefixes di-, tri-, etc. are used to indicate multiple identical substituents. (Example: 3-chloropentane) 5. Assemble the name, listing groups in alphabetical order. The prefixes di, tri, tetra etc., used to designate several groups of the same kind, are not considered when alphabetizing. Place a comma between multiple numbers. (Example: 2,3-dichloropropane) 5. Assemble the name, listing groups in alphabetical order. The prefixes di, tri, tetra etc., used to designate several groups of the same kind, are not considered when alphabetizing. Place a comma between multiple numbers. (Example: 2,3-dichloropropane)

Step 1. Find the parent chain. Where is the longest continuous chain of carbons?Where is the longest continuous chain of carbons?

Prefixes for # of Carbons 1Meth6Hex 2Eth7Hept 3Prop8Oct 4But9Non 5Pent10Dec

Endings Alkanes (all C-C single bonded parent chain) end in –aneAlkanes (all C-C single bonded parent chain) end in –ane –Methane CH 4 –Ethane C 2 H 6 –Propane C 3 H 8 Attached carbon groups (substituents) end in –ylAttached carbon groups (substituents) end in –yl –Methyl CH 3 - –Ethyl CH 3 CH 2 - –Propyl CH 3 CH 2 CH 2 – –Propyl CH 3 CH 2 CH 2 – 3-ethylpentane

Step 2. Number the parent chain. Number the parent chain so that the attached groups are on the lowest numbers Methyl is on carbon #2 of the parent chain Methyl is on carbon #4 of the parent chain GREEN is the right way for this one! Groups on 2, 3, and 5 Groups on 4, 6, and Groups on 2 and Groups on 3 and 6

Step 3. Name the attached groups. Carbon (alkyl) groupsCarbon (alkyl) groups –Methyl CH 3 - –Ethyl CH 3 CH 2 - –Propyl CH 3 CH 2 CH 2 – HalogensHalogens –Fluoro (F-) –Chloro (Cl-) –Bromo (Br-) –Iodo (I-)

Step 4. Designate where the group is attached to the parent chain. Use the numbers of the parent chain from step 2 to designate the location of the attached groups to the parent chain methyl

Step 5. Alphabetize the groups, combine like groups, and assemble. The prefixes di, tri, tetra etc., used to designate several groups of the same kindThe prefixes di, tri, tetra etc., used to designate several groups of the same kind Prefixes are not considered when alphabetizing (Example: dimethyl = m for alphabetizing)Prefixes are not considered when alphabetizing (Example: dimethyl = m for alphabetizing) Parent chain goes LASTParent chain goes LAST 1,1,1-trichloro-1- fluoromethane 1,1-dichloro-1,1- difluoromethane

Name the Alkanes

2,4-dimethylhexane 3,3-diethylpentane 2,3,4-trimethylhexane

Alkanes Example: Name the following compounds:

Alkanes 1-bromo-3-ethyl-3,4-dimethylpentane 2,2,3,6-tetramethyl-4-isopropyloctane

Draw Some Simple Alkanes 2-methylpentane2-methylpentane 3-ethylhexane3-ethylhexane 2,2-dimethylbutane2,2-dimethylbutane 2,3-dimethylbutane2,3-dimethylbutane

Alkanes Example: Write the condensed structure for the following compounds: 3,3-dimethylpentane1,2-dichloro-3-methylheptane

On packet Number 9 – tert-, sec-, n-butyl