Organic Chemistry Chapter 18

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Organic ChemistryChapter 18

• Brief Introduction to
• Organic Chemistry

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I. Introduction

• Def Chemistry of Carbon Containing Compounds
• Carbon is unique since it can form single,
  double, triple bonds with itself and with other
  atoms.
• Frequently find F, Cl, Br, I, N, O, P, S atoms in
  carbon compounds. H always present.
• Note that carbon always has 4 bonds H 1 bond O
  usually 2 N usually 3 VIIA 1 bond.
• Functional Group portion of molecule which
  controls the chemistry.
• There is a complexity to the organic molecules
  found in living systems that cannot be
  explained by any natural process.

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I. Introduction

• Can write organic structures several ways.
• Example Butane C4H10
• CH3CH2CH2CH3 CH3-CH2-CH2-CH3
• H H H H
• H C C C C H
• H H H H

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I. Introduction

• Isomers Different compounds with the same
  formula.
• Example C4H10 CH3
• CH3CH2-CH2-CH3 or CH3 CH CH3
• Are over 6 trillion isomers of C40H84

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I. Introduction

• Isomers Are three basic types
• 1) Structural Completely different structures
• 2) Geometric Differ in Geometry cis trans
• 3) Stereo Differ in their 3D R S
• Examples Butane vs 2-methylpropane
• cis trans 1,2-dibromoethene
• R S bromochlorofluoromethane

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II. Nomenclature

• Need a system that can name an infinite number of
  molecules and one that can obtain the structure
  from the name.
  F F
• An example is 1,2-difluoroethene CHCH
• The name has three parts Prefix , Base, End
• a) prefix Tells , types where side groups
  attached
• b) Base Tells of Cs in longest continuous
  chain
• c) End Tells which functional group is present
• 1,2-difluoroethene
• Note numbers are separated by a comma and
  numbers letters are separated by a dash.

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II. Nomenclature - Examples

• CH3-CF2-CH3 2,2-difluoropropane
• CH3-CH2-CH2-OH 1-propanol
• CH3-CHCH-CH3 2-butene
• CH3-CICH-CH3 2-iodo-2-butene

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III. Hybrid Atomic Orbitals (HAO)

• sp1, sp2, sp3 HAO
• - C, N, O use HAO when form bonds.
• - 2s and 2p orbitals rearrange to fit the bonding
  situation.
• - When form sp3 have all single bonds (104-109o)
• - When form sp2 have one double bond (120o)
• - When form sp1 have two double bonds (or triple)
  (180o)
• Predicting HAO
• - Draw Lewis structure of organic
• - Note how many double bonds use above rules
• Example - Determine HAO used by C, O N
• CH3-CHO CH2CCH2 CH3-NHCH3
• sp3 sp2 sp2 sp2 sp1 sp2 sp3 sp3 sp3

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IV. Functional Groups

• Alkanes - Contain all single bonds
• - Methane CH4
• - Ethane CH3-CH3
• - Propane CH3-CH2-CH3
• - Butane CH3-CH2-CH2-CH3
• - Pentane, Hexane, Heptane, Octane, etc.
• Alkenes - Contain 1 or more double bonds
• Ethene CH2CH2
• Propene CH3-CHCH3
• Butene Two structural isomers
• (1-butene 2-butene)

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IV. Functional Groups

• Cyclic Alkanes and Alkenes
• Cyclopropane, Cyclobutane, Cyclopentene
• Aromatics Contain Benzene, C6H6

Uses sp2 HAO, Flat, Carcinogen
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III. Functional Groups

• O
• Alcohols R OH except R-C-OH
• Ethers R O R
• Aldehydes R CHO

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III. Functional Groups

• O
• Ketones R-C-R
• O
• Carboxylic Acids R-C-OH
• O
• Esters R-C-OR

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III. Functional Groups

• Amines R-NH2 R-NH-R
• O
• Amides R-C-NH2
• Halides R-Cl Br I or F

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IV. Resonance

• - Some compounds like benzene can exist in more
  than one form by altering the position of the
  double bonds. We call this resonance true
  structure is combination of the resonance forms.