ALKYNES

-Characterized by C C triple bond(s) -Classified as unsaturated hydrocarbons -empirical formula = C n H 2n-2 (applies when the molecule only has one triple bond)  C n H 2n-2, n=5 = C 5 H 8

ALKYNES Properties: -Are hydrophobic like all hydrocarbons -Have higher boiling points than alkanes and alkenes due to their ability to stack

ALKYNES Some IUPAC names of alkynes: All alkynes have the suffix “yne” ethynepropynebut-1-yne

ALKyNES IUPAC naming system: prefixsuffix Number of carbons in the longest chain family butyneEx: -#- Location number -1-

ALKYNES IUPAC naming system: Name the following alkynes: hex-1-yne hex-3-yne

ALKYNES IUPAC naming system: Name the following alkynes: 4-methylhex-2-yne 5-ethyl-4,6,7-trimethylnon-2-yne The triple bond has a higher numbering priority than the alkyl and halide substituents

ALKYNES IUPAC naming system: Name the following alkynes: hex-4-en-1-yne 3-ethylhept-1-en-4-yne Alkenes are ordered first in the name, and the “e” ending is dropped. Generally, double bonds and triple bonds have equal numbering priority* (aim to get the lowest numbers)

ALKYNES IUPAC naming system: Name the following alkynes: hex-1-en-5-yne hex-5-en-1-yneor *Double bonds have higher priority than triple bonds whenever there is ambiguity in their numbers. This uses the rule where alpha-order is final tie-breaker like before.

ALKYNES IUPAC naming system: Name the following alkynes: cyclononynecyclooct-1-en-4-yne

ALKYNES IUPAC naming system: Name the following alkyne: 3,4,5-trichloro-8,9-diethyl-5,7,7-trifluorocyclononyne

ALKYNES Drawing alkynes: Draw the following alkynes using line diagrams non-2-yne The triple bond cannot bend, so the bonds adjacent to a triple bond must be straight. non-1-yne

ALKYNES Drawing alkynes: Draw the following alkynes using structural diagrams 4,5-dibromohex-2-yne C H Br C H H H CC H C H H C H 1,2-dimethylcyclooct-1-en-4-yne C C C C C C CHH H C H H H H H H H C C H H H H

ALKENES RECALL: Name the following alkenes: 4-methylpenta-1,3-dienehepta-1,3,6-triene When there is more than one double bond, add the letter “a” to the end of the prefix (i.e. buta)

ALKYNES Multiple Double Bonds AND/OR Triple Bonds: octa-2,4-dien-6-yne When there is more than one triple bond, AND a double bond, add the letter “e” to the end of the double bond sufix -ene dec-1-ene-4,9-diyne When there is more than one double bond AND a triple bond, add the letter “a” to the end of the prefix (i.e. buta)

nona-5-7-diene-1,3-diyne ALKYNES undeca-1,6,-diene-3,9-diyne