Introduction to Organic Chemistry
• Mostly covalent bonding
• Low melting point
• Most water insoluble
• Non-electrolytes
• Reactions usually slow
• Forms four covalent bonds since carbon has 4 valence electrons
• Can be:
– Four single bonds
– 1 double bond and two single bonds
– 2 double bonds
– One triple bond and one single bond
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• Contain only carbon and hydrogen atoms
• Derivatives ( Substituted hydrocarbons) are formed by adding other elements (O,
S, N, P, Cl, etc…) or functional groups
– Aliphatic hydrocarbons are non-aromatic hydrocarbons
– Saturated hydrocarbons (known as
“Alkanes”) possess all single bonds between carbons
• Names end in –ane (methane, ethane, propane, butane, pentane, hexane, etc…)
• Unsaturated hydrocarbons possess one or more double (Alkenes) or triple
(Alkynes) bonds between carbon atoms
– Names end in –ene (propene, etc..) or –yne
(butyne, etc…)
• Can be cyclic (rings) or acyclic
– Aromatic hydrocarbons contain benzene rings (6 C ring structure with conjugated double bonds)
• Can be branched ( alkyl groups)
– Branch name ends in –yl (methyl, ethyl, etc…)
• Cycloalkanes
– Saturated hydrocarbons, but the carbon atoms are in a ring structure
– Cyclopropane, Cyclobutane, etc…
• Cycloalkenes
– Unsaturated hydrocarbons, but the carbon atoms are in a ring structure
– Cyclopropene, Cyclobutene, etc…
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• Expanded:
– Shows all bonds and atoms
H
H C
H
H
• Condensed:
– Partially abbreviated formulas
– CH
3
-CH
3 or CH
3
CH
2
CH
3
• Skeletal :
– Show only C atoms and other atoms except H bonded to C atoms and bonds holding them
(assume everything bonded to carbon atoms are hydrogen atoms)
– C-C-C-C-C or C-C-C-C-C-C
C
• Line-Angle:
– All points and ends are carbon atoms unless other atom shown
– Very common
– Fill all available bonds with hydrogen atoms unless another atom is shown
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OH
PENTANE
O
DIETHYL ETHER
ISOPROPYL ALCOHOL
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• Carbons are classified as primary, secondary, tertiary, or quaternary based on the number of carbons bonded to it
– Primary = carbon atom bonded to one other carbon atom
– Secondary = carbon atom bonded to two other carbon atoms
– Tertiary = carbon atom bonded to three other carbon atoms
– Quarternary = carbon atom bonded to four other carbon atoms
How many primary, secondary, tertiary, and quarternary carbons are there? Where?
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• Chemicals that have the same molecular formula, but different arrangement of atoms
– Thus they are different substances
• Constitutional/Structural isomers: differ in arrangement of carbon atoms
– Methane, ethane and propane have no isomers
– Butane = C-C-C-C or isobutane C-C-C
C
* both have 4 carbons and 10 hydrogens
• Cis-trans stereoisomers only for cyclicalkanes or alkenes (double bonded unsaturated)
– These isomers have the same structural formula, but differ in arrangement of atoms in space due to restricted rotation
• Cis = same substituent on same side
• Trans = same substituent on opposite side
– Stereoisomers are usually very different physiologically and have very different physical properties
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• These chemicals have the same carbon structure, but differ in the position of same substituent, alkyl group, or functional group
– 1-Bromopropane, 2-Bromopropane
– 2-Bromopentane, 3-Bromopentane, 1-
Bromopentane
– 1,1-Dibromocyclohexane, 1,2-
Dibromocyclohexane, 1,3-Dibromocyclohexane,
1,4-Dibromocyclohexane
Br
Br
Br
Br
Br
Br
Br
Br Br Br
Br
Br
Br
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• These are atoms or groups of atoms added to a hydrocarbon that gives a potential site of reaction for the compound
• The insertion of a functional group also changes the chemical and physical properties of the substance
• Functional groups form the various
Classes of Organic Compounds
• In chemical reactions, one functional group is usually converted into another
• In organic chemistry, the symbol R is shorthand to designate hydrocarbon
• Thus, R-Cl is a shorthand way to express a halide and R-OH is short for an alcohol
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1.Alkene
2.Halide
3.Alcohol
4.Ether
5.Amine
6.Thiol
7.Disulfide
8.Aldehyde
9. Ketone
10. Carboxylic Acid
11. Ester
12. Amide
Cl
OH
NH
2
O
SH
S
S
O
O
H
O
O
OH
O
CH
3
NH
2
O
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