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What is Organic Chemistry?
“… a chemistry subdiscipline involving the scientific study of thestructure, properties, and reactions of organic compounds and organicmaterials, i.e., matter in its various forms that contain carbon atoms”
-Wikipedia
Carbon: Why So Special?
Multiple possible shapes
Bonds to itself very nicely (practically infinitely)
Four valence electrons
Forms covalent bonds with MANY other atoms
Especially hydrogen
Carbon: Why So Special?
Multiple possible shapes
Bonds to itself very nicely (practically infinitely)
Four valence electrons
Forms covalent bonds with MANY other atoms
Found EVERYWHERE in nature
Drawing Organic Molecules
Every organic molecule has carbon
Why explicitly draw them then?
Hydrogens are cumbersome
So many… 99% of which can be assumed
Don’t show hydrogen atoms on carbon atoms
Only specify “heteroatoms,” i.e. atoms other than carbon
Organic Molecules: Alkanes
Organic molecules which:
Have only carbons and hydrogens (hydrocarbons)
Contain only single bonds
Systematic naming conventions
IUPAC- “International Union of Pure and Applied Chemists”
# of C atoms Prefix
1 Meth-
2 Eth-
3 Prop-
4 But-
5 Pent-
6 Hex-
Organic Molecules: Alkanes
Organic molecules which:
Have only carbons and hydrogens (hydrocarbons)
Contain only single bonds
Systematic naming conventions
IUPAC- “International Union of Pure and Applied Chemists”
C4H10 C4H10
Ethane Propane
Butane
vs.
Butane?
Organic Molecules: Alkanes
Organic molecules which:
Have only carbons and hydrogens (hydrocarbons)
Contain only single bonds
Systematic naming conventions
IUPAC- “International Union of Pure and Applied Chemists”
C4H10 C4H10
Ethane Propane
Butane
vs.
2-methylpropane
Constitutional Isomers
Organic Molecules: Alkanes
Single bonds allow rotation
Newman projections
Butane
vs.
Butane
Rotamers
Organic Molecules: Alkenes
Organic molecules which:
Have only carbons and hydrogens (hydrocarbons)
Contain at least one double bond
Systematic naming conventions
IUPAC- “International Union of Pure and Applied Chemists”
Ethene Propene
1-butene 2-butene2-methylpropene 2-butene
Organic Molecules: Alkenes
Organic molecules which:
Have only carbons and hydrogens (hydrocarbons)
Contain at least one double bond
Systematic naming conventions
IUPAC- “International Union of Pure and Applied Chemists”
Ethene Propene
1-butene2-methylpropene 2-trans-butene
2-cis-butene
cis-trans diastereomers
Organic Molecules: Alkynes
Organic molecules which:
Have only carbons and hydrogens (hydrocarbons)
Contain at least one triple bond
Systematic naming conventions
IUPAC- “International Union of Pure and Applied Chemists”
Ethyne
Organic Molecules: Cyclic Hydrocarbons
All previous rules apply… add “cyclo” prefix
hexane cyclohexane
cyclohexene
1,3-cyclohexene
1,3,5-cyclohexene
C6H14 C6H12
Organic Molecules: Cyclic Hydrocarbons
All previous rules apply… add “cyclo” prefix
hexane cyclohexane
cyclohexene
1,3-cyclohexadiene
1,3,5-cyclohexatriene
C6H14 C6H12
Organic Molecules: Aromatics
All previous rules apply… add “cyclo” prefix
1,3,5-cyclohexatriene 1,3,5-cyclohexatriene benzene
Delocalized electrons
Additions to base organic molecules
Heteroatoms
Functional groups yield different properties
Electronegativity => dipole moments
Atomic size => steric interactions
Bond order => flexibility and entropy
Functional Group Name Structure
Alkyl halide Alcohol -ol
Ether -ether
Aldehyde -al
Ketone -one
Carboxylic acid -oic acid
Ester -ester
Amine -amine
Organic Molecules: Functional Groups
Reaction mechanisms
Describe how atoms and electrons move as reaction occurs
Show motion of atoms, electrons, bonds, etc. via arrows
Double headed and single headed arrows mean motion of two and one electron, respectively
Transition state: point during reaction coordinate at which system energy is at a maximum
Organic Reactions
Nucleophilic Substitution: SN2
Nucleophile: molecule which “likes” positive centers
Negatively charged atoms/molecules
Highly polar molecules
Lewis bases- electron donation
Takes place in one single step
Transition state:
Nucleophile: molecule which “likes” positive centers
Negatively charged atoms/molecules
Highly polar molecules
Lewis bases- electron donation
Takes place in one single step
Transition state:
Nucleophilic Substitution: SN2
What’s different in this reaction?
“Steric hindrance” Bulky groups around positive site hinder attack by nucleophile
Nucleophilic Substitution: SN1
What’s different in this reaction?
“Steric hindrance” Bulky groups around positive site hinder attack by nucleophile
Nucleophilic substitution occurs via a different mechanism in this case SN1 reactions
Nucleophilic Substitution: SN1
Diene + “dienophile” = cyclic hydrocarbon system
Dienophile is a molecule which “likes” dienes… typically alkenes with electron withdrawing groups
Useful for synthesizing medicines
Won Nobel Prize in 1950
Diels-Alder Cycloaddition
Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR)
Good for determining carbon skeleton and hydrogen environment
Infrared Spectroscopy (IR)
Good for determining presence of functional groups
Ultraviolet-visable Spectroscopy (UV-Vis)
Good for determining double/triple bonds
Mass Spectrometry (MS) Good for determining the molecular formula
Compound Validation
Induced magnetic field (mis)aligns protons
Protons also have spins: ½ and -½
Specific radio frequencies excite protons to higher energy state
Return to lower E state induces electrical signal
Signal dependent upon:
Nuclear Magnetic Resonance (NMR)
Induced magnetic field (mis)aligns protons
Protons also have spins: ½ and -½
Specific radio frequencies excite protons to higher energy state
Return to lower E state induces electrical signal
Signal dependent upon:
Nuclear shielding <- electrons shield protons from magnetic field
Nuclear Magnetic Resonance (NMR)
Induced magnetic field (mis)aligns protons
Protons also have spins: ½ and -½
Specific radio frequencies excite protons to higher energy state
Return to lower E state induces electrical signal
Signal strength dependent upon:
Nuclear shielding <- electrons shield protons from magnetic field
Peak splitting <- other, nearby protons affect spectra
Nuclear Magnetic Resonance (NMR)
Engineering Context: Medicine
Imatinib: 4-[(4-methylpiperazin-1-yl)methyl]-N-(4-methyl-3-{[4-(pyridin-3-yl)pyrimidin-2-yl]amino}phenyl)benzamide
Engineering Context: Medicine
Imatinib:
Treatment for chronic myelogenous leukemia
Cancer of the white blood cells
Caused by presence of “Philadelphia chromosome”
4-[(4-methylpiperazin-1-yl)methyl]-N-(4-methyl-3-{[4-(pyridin-3-yl)pyrimidin-2-yl]amino}phenyl)benzamide
Engineering Context: Energy
Crude Oil: A mixture of organic compounds
Alkanes Cycloalkanes Aromatics Asphaltics
Average Composition
(by weight)30% 49% 15% 6%