Chapter 2: Carbon Compounds

Hydrocarbons• Consist of only Carbon and Hydrogen Atoms

• Alkanes—Contain the Maximum # of H Atoms

• Alkenes—Hydrocarbons w/ Double Bond(s)

Ethene Propene Butadiene

CH4 H3C CH3

Methane Ethane Propane

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

H—Br

C═O

• Electronegativity Difference Pulls ElectronDensity Toward More Electronegative Atom

• This Creates What is Called a Dipole

• Unit of Dipole Moment Measure: Debye

H Br

For Bonds, Dipole Moment is Indicated w/ Arrow From Leastto 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)

Cl

Cl

Br

Br

Cl Cl

Br Br

NON POLAR POLAR

trans-dichloroethene

trans-dibromoethene

cis-dichloroethene

cis-dibromoethene

Functional Groups

1. Alkyl Groups(R)

Alkanes can be Generally Represented as R-H

Parent HC Alkyl Group Abbreviation

Methane methyl Me

Ethane ethyl Et

Propane propyl Pr

isopropyl iPr

Functional Groups

2. Alkyl Halides

ClCl

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

• 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

OHOH

OH

1o Alcohol 2o Alcohol 3o Alcohol

Functional Groups

4. Ethers

OO

O

OO

dimethyl ether diethyl ether ethyl propyl ether

ethylene oxide tetrahydrofuran

• Name “sides” of ether in alphabetical order

Functional Groups

5. Amines

• Note: amines are utile as bases in organic reactions

1o Amine 2o Amine 3o Amine

NH2H3CHN N

NH2

NH

NH

ethyl amine diethyl amine piperidine

Functional Groups

6. Hydrazines

• Note: hydrazines react with aldehydes/ketones

H2N NH2 N NNH

NH

N

N NOT:

NH

HN

Functional Groups

7. Carbonyls: Aldehydes and Ketones

• Note: C=O common link between aldehydes/ketones

R H

O

R R

O

R R'

O

Aldehyde Ketones

H H

O

O

O O

O

Formaldehyde Acetone Cyclohexanone

Propanal Ethyl methyl ketone

Functional Groups

8. Carboxylic Acids

• Question: What helps makes this functionality acidic?

H

O

OH

O

OH

O

OH

O

OH

Formic Acid Acetic Acid

Benzoic Acid Propanoic Acid

Functional Groups

9. Esters

• Note: CYCLIC esters are a special case called LACTONES

O

O

O

O

O

O

O

O

ethyl acetate propyl acetate

ethyl propionate methyl benzoate

Functional Groups

10. Amides

• Note: CYCLIC amides are a special case called LACTAMS

• Amides have restricted rotation about the C-N bond. Why?

NH2

O

NH

O

N

O

acetamide N-methyl acetamide N,N dimethylacetamide

Functional Groups

11. Nitriles (Cyano)

• See Table 2.3 for a Good Summary of Functional Groups

CN CNCN

acetonitrile(ethanenitrile)

butanenitrile propenenitrile(acrylonitrile)

Multiple Functional Groups; 1 Molecule

O N

O

O

O

O

N OH

Cl

OMe

Cryptophycin 3

Intermolecular Forces

1. Van der Waals Interactions

2. Dipole-Dipole InteractionsConsider how molecules with permanent dipoles align

3. Hydrogen BondingVery strong electron delocalizations

4. IonicVery strong electrostatic interactions

Hydrogen Bonding

OH

H

O

O

H

O H

• H-Bonds nearly linear (O-H-O)

• Electrons from an O lone pair *(OH)