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Organic Chemistry. The chemistry of carbon and carbon-based compounds. C=C. –C–C–. –C=C–. Why is carbon so special?. Carbon is unique among the elements because: . --. it can have up to four bonds per C atom . single, double, or triple bonds . . --.
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Organic Chemistry The chemistry of carbon and carbon-based compounds
C=C –C–C– –C=C– Why is carbon so special? Carbon is unique among the elements because: -- it can have up to four bonds per C atom single, double, or triple bonds -- it can form REALLY long chains of C atoms -- its bonds are strong
Organic Chemistry Organic Chemistry is everywhere! Smells & tastesfruits, chocolate, fish, mint MedicationsAspirin, Tylenol, Decongestants, Sedatives Addictive substancesCaffeine, Nicotine, Alcohol, Narcotics Hormones/NeurotransmittersAdrenaline, Epinephrine Food/NutrientsCarbohydrates, Protein, Fat, Vitamins GeneticsDNA, RNA Consumer productsPlastics, Nylon, Rayon, Polyester
Drawing Organic Structures Butane: C4H10 Shortcuts make structures easier & faster to draw Lewis Structure Carbon Atoms • Line Structure • Only shows bonds • C atoms assumed at each end and intersection of bonds • H atoms not shown • Assume 4 bonds to each C • Fulfill C’s 4 bonds by adding H’s Condensed Structures CH3CH2CH2CH3 CH3(CH2)2CH3
Types of Organic Compounds Classified according to functional groups Alkane Alcohol Carboxylic acid Alkene Ether Amine Alkyne Ketone Amide Haloalkane Aldehyde Amino acid
Big Idea in Organic Chemistry Structure controls Function Each functional group has predictable reactivity
Naming Alkanes (or Paraffins) Made only of C and H All C atoms are tetrahedral(only C-C single bonds) General formula = CnH2n+2(CH4, C2H6, C3H8, C4H10, etc.) Alkanes are named based on the number of carbons in the longest chain!
Naming Basic Alkanes # of C atoms Alkane Alkyl substituents CH4 CH3CH3 CH3CH2CH3 CH3CH2CH2CH3 Methane Ethane Propane Butane Pentane Hexane Heptane Octane Nonane Decane Methyl Ethyl Propyl etc. -CH3 -CH2CH3 -CH2CH2CH3 1 2 3 4 5 6 7 8 9 10 Root: number of C atoms Suffix: functional group (-ane for alkanes) (-yl for alkyl groups)
Linear vs. Branched Alkanes • General formula = CnH2n+2 (CH4, C2H6, C3H8, C4H10) • Can have linear or branched alkanes C5H12 • Same molecular formula, different structure: structural isomers • Branches, including other atoms bonded, are called substituents. Common non-carbon ones are: –I –NO2 –NH2 –F –Br nitro amino fluoro bromo iodo
Naming Branched Alkanes (IUPAC) Octane 4-ethyl • Root name: name of longest continuous C chain (parent chain) • Two equally long? Choose the one with more branches • Number C atoms in chain, starting at end with first branch • Identify substituents, give each a number (C it is connected to) • Two or more identical substituents: use prefixes (di-, tri-, tetra-, etc.) • List substituents alphabetically before root name • Do not alphabetize prefixes • Punctuation: commas separate numbers from each other hyphens separate numbers from names no space between last substituent & root name 2 6 4-ethyl-3,5-dimethyloctane 8 5 4 3 7 1 3-methyl and 5-methyl = 3,5-dimethyl
Provide each counterpart. 1 2 5-ethyl-3-methyl octane 3 7 5 4 8 6 (C11H24) 4-ethyl-2-methylhexane (C9H20)
Naming Alkanes Practice a. 2,4-dimethylpentane b. 2,4-dimethylhexane c. 2,4,6-trimethylheptane d. 3-ethyl-2-methylpentane e. 2,3-dimethylpentane f. 2,2-dimethylhexane g. 2,5-dimethylhexane h. 4-methylheptane
Isomers The fat dog shook himself, and then rolled over on the wet rug. OR The dog shook the fat rug, then rolled over and wet on himself. These two statements use the same words... but have very different meanings! Likewise, isomers may have the same formula, but have very different structures…
Structural Isomer Practice • On piece of your own paper, draw AND name ALL of the isomers for the following alkanes: # isomers Formulas C5H12 C6H14 C7H16 3 5 9 Some of your drawings may look different, but they are only different structures (isomers) if they also have different names If you complete that, try to draw and name all of the isomers for octane (C8H18) in your HW. There are 18 of them!
Structural Isomers: C5H12 pentane 2-methylbutane 2,2-dimethylpropane
Structural Isomers: C6H14 hexane 2,3-dimethylbutane 2-methylpentane 2,2-dimethylbutane 3-methylpentane
Structural Isomers: C7H16 heptane 2,2-dimethylpentane 2-methylhexane 2,3-dimethylpentane 3-methylhexane
Structural Isomers: C7H16 2,4-dimethylpentane 3-ethylpentane 3,3-dimethylpentane 2,2,3-trimethylbutane
Naming Practice 3 6 2 2 4 1 1 4 5 5 6 3 Two equal numbering options? Number based on alpha order 5-chloro-2-fluorohexane 2-chloro-4-fluoro-2,3-dimethylpentane 2-chloro-5-fluorohexane 2-bromo-3-ethyl-4-iodopentane 2-bromo-4-chloro-3-isopropylpentane
Br Cl I I NO2 NH2 NO2 Provide each counterpart. 3-bromo-2-chlorohexane 2-ethyl-1,1-diiodo heptane 2-methyl-1-nitrobutane 2-amino-6-nitro-3-propyl heptane
Structural Isomers What are the possible structural isomers of C3H7Br? 1-bromopropane 2-bromopropane What are the possible structural isomers of C4H9Cl? 1-chlorobutane 2-chloro-2-methylpropane 1-chloro-2-methylpropane 2-chlorobutane
Cycloalkanes • Alkanes with closed ring(s) of C atoms • General formula: CnH2n (C3H6, C4H8, C5H10, etc.) • Naming: use cyclo- prefix before alkane name cyclobutane n = 4 cyclopentane n = 5 cyclohexane n = 6 cyclopropane n = 3 C6H12 C3H6 C5H10 C4H8 • Naming substituted cycloalkanes: • 1 substituent: no numbering necessary • 2 or more substituents: lowest numbering scheme, then by alpha 1-chloro-5-methylcyclohexane 1-chloro-3-methylcyclohexane methylcyclopentane
Fun Common Names broken windowpane boxane windowpane basketane