UNIT 6 Theories of Covalent Bonding and Intro to Organic Chemistry: Nomenclature of Alkenes, Alkynes, Alcohols

Structural Isomers Have the Same Molecular Formula Draw the line angle structure of: The molecular formula of this compound is C 8 H 18. Draw three more structural isomers of octane.

:O = S = O: Valence Bond Descriptions What orbitals overlap to form each of the bonds in SO 2 ? The S-O sigma bond in each double bond is formed by the overlap of an O sp 2 hybrid orbital with a S sp 2 hybrid orbital. Each S-O pi bond is formed by the overlap of the S 3p z orbital with the O 2p z orbital. Two sp 2 orbitals on each of the O’s and one sp 2 orbital on the S are not involved in any bond.

Nomenclature of Alkenes  Number the C chain from the end that brings you to the double bond sooner, then use the alkane naming rules and -ene. IUPAC (common) H 2 C=CH 2 ethene (ethylene) H 2 C=CH-CH 3 propene (propylene)  Planar geometry around the double bond  120° bond angles to the C atoms in the double bond

Nomenclature of Alkenes geometric isomers All four are structural isomers. What are the bond angles? trans-but-2-ene bp = 1°C cis-but-2-ene bp = 4°C methylpropene bp = - 7°C but-1-ene bp = -6°C

Nomenclature of Alkenes 6,6-dichloro-5-ethyl-4-methylhept-1-ene Name this alkene. Give a VB description of the C-Cl bond. Draw the line angle structure for 1-chloro-3-methyl-1,3-butadiene

Alkynes  Contain at least one C≡C bond. Alkynes are unsaturated molecules.  The two π bonds make the geometry through the triple bond linear.  The triple bond is highly reactive, so alkynes are not found widely in nature, though they are used as intermediates in industrial processes.

Nomenclature of Alkynes  Number the C chain from the end that brings you to the triple bond sooner, then use the alkane naming rules and -yne. IUPAC (common) HC≡CHethyne (acetylene) HC≡C-CH 3 propyne  Linear geometry around the triple bond  180° bond angles to the C atoms in the triple bond

Alkynes Draw the condensed structural formula and line angle structure for 4-methylpent-2-yne. CH 3 - C ≡ C - CH - CH 3 | CH 3 CH 3 C≡CCH(CH 3 ) 2 * What is the hybridization on the starred C? What is the geometry? Give a VB description of one of the C- C pi bonds.

Alcohols  Contain the -OH (hydroxyl) group.  Alcohols are NOT bases. In fact, some can be acidic (phenol).  Can be soluble in polar solvents such as water (hydrocarbons are not soluble in water).  Primary (1°) alcohols: R – CH 2 - OH  Secondary (2°) alcohols:R - CH - R' | OH  Tertiary (3°) alcohols: R″ | R - C - R' | OH R,R',R″ designate the rest of the molecule. R represents an alkyl group.

Nomenclature of Alcohols Number the C chain from the end that brings us to the -OH group sooner, then use the alkane naming rules and -ol. 1° alcoholsIUPAC (common) CH 3 CH 2 OH ethanol (ethyl alcohol) CH 3 CH 2 CH 2 OH propan-1-ol (n-propyl alcohol) or 1-propanol * CH 3 OH*M ethanol is not primary, it’s a methyl alcohol.

Nomenclature of Alcohols Number the C chain from the end that brings us to the -OH group sooner, then use the alkane naming rules and -ol. 2° alcoholsIUPAC (common) CH 3 CHCH 3 propan-2-ol (isopropyl alcohol) |or 2-propanol OH CH 3 CHCH 2 CH 3 butan-2-ol or 2-butanol | OH

Nomenclature of Alcohols Which are primary? Secondary? Tertiary? isopropyl alcohol IUPAC: propan-2-ol or 2-propanol t-butyl alcohol IUPAC: methylpropan-2-ol ethylene glycol IUPAC: ethane-1,2-diol

Nomenclature of Alcohols 1°? 2°? 3°? Give the IUPAC name of each. Give a VB description of one of the O-H bonds.

Nomenclature of Alcohols phenol IUPAC: phenol propylene glycol glycerine, glycerol IUPAC: propane-1,2,3-triol Draw the line angle structure for 2-methyl-3-butyn-2-ol

Nomenclature of Alcohols IUPAC: 10,13-dimethyl-17-(6-methylheptan-2-yl)- 2,3,4,7,8,9,11,12,14,15,16,17- dodecahydro-1H-cyclopenta[a]phenanthren-3-ol What is the H-C-C bond angle for either of the “dashed” H’s?

Draw Line Angle and 3-D Structures

Give Condensed Structural Formula

Functional Groups - Review alkene alkyne alcohol amine (1°) ether halide R = alkyl group - X nitrile - C≡N

Functional Groups - Review aldehyde ketone carboxylic acid ester amide aromatic ring

Functional Groups Circle and label each functional group. fructose acetaminophen threonine γ-butyrolactone (GBL)