Download Chapter 2: Carbon Compounds

Chapter 2: Carbon Compounds
Hydrocarbons
• Consist of only Carbon and Hydrogen Atoms
• Alkanes—Contain the Maximum # of H Atoms
CH4
Methane
H 3C
CH3
Ethane
Propane
• Alkenes—Hydrocarbons w/ Double Bond(s)
Ethene
Propene
Butadiene
Hydrocarbons Continued
• Alkynes—Hydrocarbons w/ Triple Bond(s)
Ethyne
Propyne
1-Butyne
2-Butyne
• Alkanes: Referred to as Saturated Compounds
(Contain Maximum # of Hydrogen Atoms)
• Alkenes/Alkynes: Unsaturated Compounds;
Can React w/ H2 (Hydrogenation Reactions)
Aromatic Compounds: Benzene
• Benzene/Aromatics are Special Class
• Understood in Terms of Kekulé Structures or MOs
Polar Covalent Bonds
H—Cl
• Electronegativity Difference Pulls Electron
Density Toward More Electronegative Atom
H—Br
• This Creates What is Called a Dipole
C═O
• Unit of Dipole Moment Measure: Debye
H
Br
For Bonds, Dipole Moment is Indicated w/ Arrow From Least
to Most Electronegative; What About Molecular Dipoles?
Polar and Nonpolar Molecules
Polar
Nonpolar
NH3
CO2
H2O
BH3
CH3Cl
CH4
CH2Cl2
CCl4
CH3CH2OH
Benzene
H3C-O-CH3
Diatomics (Cl2, Br2, etc.)
• Look at Individual Dipole Moments; Check for Net
Polar and Nonpolar Molecules (2)
NON POLAR
POLAR
Cl
Cl
trans-dichloroethene
Cl
Cl
cis-dichloroethene
Br
Br
Br
Br
trans-dibromoethene
cis-dibromoethene
Functional Groups
1. Alkyl Groups (R)
Parent HC
Alkyl Group
Abbreviation
Methane
methyl
Me
Ethane
ethyl
Et
Propane
propyl
Pr
isopropyl
iPr
Alkanes can be Generally Represented as R-H
Functional Groups
2. Alkyl Halides
Cl
Cl
Cl
1o Halide
2o Halide
3o Halide
• Look at Carbon w/ Halide attached
• 1 C Attached—Primary; 2 C Attached—Secondary
3 C Attached--Tertiary
Functional Groups
3. Alcohols
OH
OH
OH
1o Alcohol
2o Alcohol
3o Alcohol
• Look at Carbon w/ Alcohol attached
• 1 C Attached—Primary; 2 C Attached—Secondary
3 C Attached—Tertiary
• Replace O with S; now have a Thiol
Functional Groups
4. Ethers
O
O
O
dimethyl ether
diethyl ether
ethyl propyl ether
O
O
ethylene oxide
tetrahydrofuran
• Name “sides” of ether in alphabetical order
Functional Groups
5. Amines
H3C
NH2
1o Amine
HN
N
2o Amine
3o Amine
NH
NH2
N
H
ethyl amine
diethyl amine
piperidine
• Note: amines are utile as bases in organic reactions
Functional Groups
6. Hydrazines
NH
H2N
N
NH2
N
NH
H
N
N
NOT:
N
N
H
• Note: hydrazines react with aldehydes/ketones
Functional Groups
7. Carbonyls: Aldehydes and Ketones
O
R
O
H
R
O
R
Aldehyde
R'
Ketones
O
O
O
H
R
H
Formaldehyde
O
Propanal
Acetone
Cyclohexanone
O
Ethyl methyl ketone
• Note: C=O common link between aldehydes/ketones
Functional Groups
8. Carboxylic Acids
O
H
O
OH
OH
Formic Acid
Acetic Acid
O
OH
OH
O
Benzoic Acid
Propanoic Acid
• Question: What helps makes this functionality acidic?
Functional Groups
9. Esters
O
O
O
O
ethyl acetate
propyl acetate
O
O
O
O
ethyl propionate
methyl benzoate
• Note: CYCLIC esters are a special case called LACTONES
Functional Groups
10. Amides
O
O
NH2
acetamide
O
N
H
N-methyl acetamide
N
N,N dimethyl
acetamide
• Note: CYCLIC amides are a special case called LACTAMS
• Amides have restricted rotation about the C-N bond. Why?
Functional Groups
11. Nitriles (Cyano)
CN
acetonitrile
(ethanenitrile)
CN
butanenitrile
CN
propenenitrile
(acrylonitrile)
• See Table 2.3 for a Good Summary of Functional Groups
Multiple Functional Groups; 1 Molecule
O
O
O
N
O
O
N
H
Cryptophycin 3
Cl
O
OMe
Intermolecular Forces
1. Van der Waals Interactions
2. Dipole-Dipole Interactions
Consider how molecules with permanent dipoles align
3. Hydrogen Bonding
Very strong electron delocalizations
4. Ionic
Very strong electrostatic interactions
Hydrogen Bonding
O
H
O
H
O
H
O
H
• H-Bonds nearly linear (O-H-O)
• Electrons from an O lone pair Æ σ*(OH)