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ORGANIC CHEMISTRY. 1.3 The chemistry of carbon / hydrogen containing compounds. HYDROCARBONS. THE SIMPLEST TYPE OF ORGANIC COMPOUNDS. HYDROCARBONS - CONTAIN ONLY C, H. H. H. H. H. H. H. C. H. H. H. H. C. C. H. C. H. C. C. C. H. C. H. C. H. H. H. H. C. H. H.
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ORGANIC CHEMISTRY 1.3The chemistry of carbon / hydrogen containing compounds
HYDROCARBONS THE SIMPLEST TYPE OF ORGANIC COMPOUNDS HYDROCARBONS - CONTAIN ONLY C, H
H H H H H H C H H H H C C H C H C C C H C H C H H H H C H H H H H H H H C H H H H C C H H C C C C H H H C H H H H H H H H H H C C C C C H H C C C H H H H H HYDROCARBONS at least one triple bond ALKYNES
H H H H H H C H H H H C C H C H C C C H C H C H H H H C H H H H H H H H C H H H H C C H H C C C C H H H C H H H H H H H H H H C C C C C H H C C C H H H H H COMMON HYDROCARBON TYPES only single bonds Saturated hydrocarbons at least one double bond Unsaturated hydrocrabon at least one triple bond ALKYNES
HYDROCARBONDERIVATIVES One or more H’s are replaced with an atom of O, N, S, F, Cl, Br, I
H H H H H C C H C C Cl C H H H H H H H H H H C H H C H C H C H O C C H C H C H H C H OH C H H H H H H HYDROCARBON DERIVATIVES
Saturated Hydrocarbonscont’d Fig. 1.2 Terms for organic compounds. 3-6)
H H H H H H C H H H H C C H C H C C C H C H C H H H H C H H H H H H H H C H H H H C C H H C C C C H H H C H H H H H H H H H H C C C C C H H C C C H H H H H 1.4 Alkanes • Acyclic (no rings) = alkane • Cyclic (contains rings) Section 1.12
1.4 Alkanes (cont.) • Are acyclic “saturated” hydrocarbons. • Contain only single bonds C-C • Every carbon is sp3 (tetrahedral) • General formula of alkanes is CnH2n+2 • CH4 • C2H6 • C3H8
1.4 Alkanes • Fig. 1.3 Molecular structures of (a) methane, (b) ethane, and (c) propane, the three simplest alkanes.
1.5 Structural formulas • Expanded (Lewis structure) H H H H H H | | | | | | H-C-H H-C-C-H H-C-C-C-H | | | | | | H H H H H H Methane Ethane Propane THESE TAKE A LOT OF SPACE TO DRAW THEY TAKE A LONG TIME TO DRAW
1.5 Structural formulas • Condensed (easier and faster to draw) Methane CH4 Ethane CH3-CH3 Propane CH3-CH2-CH3
1.5 Structural formulas • Condensed Octane: CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH3 • More condensed CH3-(CH2)6-CH3
1.6 Alkane Isomerism Linear carbon chain Octane: CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH3 Branched carbon chain (acyclic) CH3 | CH3-CH-CH2-CH2-CH2-CH2-CH3
CONSTITUTIONAL ISOMERISM • Same molecular formula, different connectivity of the atoms • As the #C increase the #isomers increases very rapidly (Table 1.1)
1.7 Conformations of alkanes MOST ATOMS ATTACHED BY A SINGLE BOND ARE FREE TOROTATEAROUND THE BOND The relative orientation of the atoms is called a CONFORMATION HOW MANY CONFORMATIONS ARETHERE?
H C H C H C H 3 3 H 3 H H H H C H H 3 H H H C H C H 3 C H 3 3 C H 3 H H H H H H C H 3 H C H C H H 3 3 H H C H H 3 H H H CONFORMATIONS OF BUTANE SAWHORSE PROJECTIONS OF PREVIOUS SLIDE SYN ANTI C C C C GAUCHE GAUCHE C C C C ECLIPSED ECLIPSED C C C C
1. 8 IUPAC RULES systematic nomenclature I nternational U nion of P ure and A pplied C hemistry colloquially: “eye-you-pac”
FEATURES OF THE IUPAC SYSTEM It is a system where every compound (even isomers) has a unique name. If the rules are followed, everyone gets the same name for a given compound. Once given the name, anyone can draw the structure of the compound. WORKS BOTH DIRECTIONS IUPAC STRUCTURE NAME
IUPAC METHOD 1. Find the longest continuous chain of carbon atoms and name it using the linear alkane names. 2. Number the chain starting from the end nearest a branch.
IUPAC METHOD 3. Give each substituent a name based on the number of carbon atoms it has. 4. Give each substituent a locant number determined by its location on the chain. 5. Assemble the name.
RULE 1. FIND THE LONGEST CONTINUOUS CHAIN OF CARBON ATOMS AND NAME IT C-C C-C-C-C-C-C-C-C-C C 9 it won’t always be the horizontal one as shown here NONANE all possibilites must be examinedtry these also …….. C-C C-C C-C-C-C-C-C C-C-C- C-C-C C- -C-C-C-C-C C 6 8 C
RULE 2. Number the chain starting from the end nearest a branch nonane C-C 1 2 3 4 5 6 7 8 9 C-C-C-C-C-C-C-C-C C
RULE 3. Give each substituent a name based on the number of carbon atoms it has. substituent nonane C-C 1 2 3 4 5 6 7 8 9 C-C-C-C-C-C-C-C-C C substituent Groups attached to the main chain are called substituents.
(substituents) methyl ethyl propyl butyl pentyl hexyl heptyl octyl nonyl decyl
RULE 3. Give each substituent a name based on the number of carbon atoms it has. ethyl nonane C-C 1 2 3 4 5 6 7 8 9 C-C-C-C-C-C-C-C-C C methyl
Rule 4. Give each substituent a locant number determined by its location on the chain. ethyl 4- nonane C-C 1 2 3 4 5 6 7 8 9 C-C-C-C-C-C-C-C-C C 2- methyl
RULE 5. Assemble the name. “ane” MAIN CHAIN STEM LOCANT SUBSTITUENT ENDING number suffix word word name of the substituent indicates the type of compound indicates position of the substituent on the chain indicates the number of carbon atoms in the chain
PUNCTUATION RULES 1. Numbers are separated from words by hyphens 2-methyl……. 2. Numbers are separated from numbers by commas. 2,3- …….. example coming shortly • Substituents are named in alphabetical • order ……4-ethyl-2-methyl…. 4. All words are joined - no breaks ……methylnonane
ASSEMBLING A NAME 4-ethyl nonane C-C 1 2 3 4 5 6 7 8 9 C-C-C-C-C-C-C-C-C C 2-methyl 4-ethyl-2-methylnonane
ORGANIC NOMENCLATURE 4 3 2 1 butane 2- methyl 1. find longest chain and name 2. number from end nearest a branch 3. name substituents 2-methylbutane 4. locant number 5. assemble name
1 2 3 4 5 Name this compound
4 3 2 1 5 6 7 Name this compound
Use multipliers if there areMORE THAN ONEof the same substituent DI- TRI- TETRA- PENTA- HEXA- HEPTA- OCTA- NONA- DECA- 2345678910 These are ignored when alphabetizing
How would you name this one? Every substituent must get a number 1 2 3 4 5 6