carbon compound matrikulasi fkik uin

7/29/2019 Carbon Compound Matrikulasi Fkik Uin

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Organic Chemistry

Muh. Yanis Musdja

The Study of the

Compounds of Carbon


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Carbons Place on the

Periodic Table


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Why does Carbon form so

many interesting compounds?

Easily forms bonds with other C atoms.

Forms double and triple bonds with other C atoms.

Can form long chains (and rings) of C-C bonds.

Ubiquitous/Found everywhere.

Depending on bonding (presence of single, double,or triple bonds) carbon compounds can exhibittetrahedral, trigonal planar or linear geometries

Though carbon and hydrogen form the backbonestructure, carbon can also bond to other elements,like O and N, which are called heteroatoms


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Carbon Skeletons

Since carbon bonds four times, it can assumea very complex set of bonding arrangements.

Single bonded carbons can rotate relative to

one another, so arrangements can be

represented in different ways, as shown

below:


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H

H

H

A C atom single-bonded

to one other atom gets

three H atoms.

C C


to two other atoms gets

two H atoms.

C C C

H

H


to three other atoms gets

one H atom.

C C C

C

H


to four other atom is

already fully bonded (no

H atoms).

C C C

C

C H

H

A double- and single-

bonded C atom or a

triple-bonded C atom is

treated as if it were

bonded to three other

atoms.

CC C

C C

H

H

A double-bonded C atom

is treated as if it were

bonded to two other

atoms.

CC

Hydrogen Skins


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Hydrocarbon Representations

C C H

H

H

C

H

HH

H

C

H

H

C

H

H

C

H

H

H Expanded Structure

CH3CH2CH2CH2CH2CH3 Condensed Structure

Bond-line Representation

C6H14 Molecular Formula


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IsomersNote that for the formula C6H14, several possible structures

exist. These alternate forms are called structural isomers.

Note that each of these isomers is a different compound

with different properties - and a different name.

CH3CH2CH2CH2CH2CH3

CH3CHCH2CH2CH3

CH3

CH3CH2CHCH2CH3

CH3

CH3CHCHCH3

CH3

CH3

One more isomer exists. Can you suggest what it is?


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Functional Groups

Groups of atoms bonded in a particular way. They tend to

act as a unit and react in a similarway despite the rest

of the compound.

Many functional groups contain electronegative elements

(N,O) and contain polar bonds.

Incomplete list of Functional groups:

1. -C=C- alkene

2. -CC- alkyne

3. -C-OH alcohol

4. -C-O-C- ether

5. -C-NH2 amine


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Most basic organic compounds: hydrocarbons

Hydrocarbons contain only the elements C and H. They

are all non-polar. They are classified by the types ofC/C bonds they contain:

1. C-C single bonds only alkanes

2. C=C double bonds alkenes

3. CC triple bonds alkynes

4. Alternating double and single aromatic


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Examples

Alkane: CH3CH2CH2CH2CH3

Alkene: CH2=CHCH2CH2CH3 or

Alkyne: CHC-CH2CH2CH3 or

Aromatic:


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Hydrocarbon Nomenclature

Number of

C atomsRoots

1

2

3

4

5

6

8

7

9

meth-

eth-

prop-

but-

hex-

pent-

hept-

oct-

non-

dec-

PREFIX + ROOT + SUFFIX

10

Note that

beginning

with 5 Cs,

the roots are

numerical


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Rules for Naming AlkanesNote that alkanes contain only single bonds and have the

generalized formula CnH2n+2

Rules for Naming Organic Compounds


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Alkane Nomenclature Examples

Suggest appropriate names for the following:

CH3CHCH2CH2CH3

CH3

CH3CHCHCH2CH3

Br

CH3

CH3CHCH2CHCHCH3

CH3

CH3

Cl

CH3CH2CHCHCH2CHCH3

CH2CH3

Br

CH3


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Alkane Nomenclature Examples (II)

Suggest appropriate names for the following:

CH3CHCH2CH2CH3

CH3

CH3CHCHCH2CH3

Br

CH3

CH3CHCH2CHCHCH3

CH3

CH3

Cl

CH3CH2CHCHCH2CHCH3

CH2CH3

Br

CH3

2-methylpentane

2-bromo-3-methylpentane

4-chloro-2,5-dimethylhexane 4-bromo-5-ethyl-2-methylheptane


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Alkane Nomenclature (III)

Suggest reasonable structures for the following names:

5-bromo-2,2-dimethyloctane 3-ethyl-2,3,4-trimethylhexane


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Alkane Nomenclature (IV)

Suggest reasonable structures for the following names:

5-bromo-2,2-dimethyloctane 4-ethyl-2,3,5-trimethylheptane

CH3CCH2CH2CHCH2CH2CH3

CH3

CH3

Br

CH3 CH CH CHCH CH2 CH3

CH3

CH3

CH2H3

CH3


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Cycloalkane Representations

C

C C

H H

H

HH

H

C

C C

CH

H

H

H

H

H H

H

cyclopropane cyclobutane


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Cycloalkanes

Cycloalkanes contain rings, and have the generalized

formula: CnH2n Cycloalkanes are usually representedby polygons, as shown below:

Cyclopropane Cyclobutane

Cyclopentane Cyclohexane


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Cycloalkane NomenclatureWhen only one substituent is on the ring, numbering is not necessary.

Chlorocyclohexane

When two or more substituents are present, the substituent that is first

alphabetically is assumed to be on carbon one, and the others are

numbered, clockwise or counter-clockwise to give the smallest number

arrangement.

1-chloro-3-methylcyclopentane

ClCl

Cl

CH3CH3

Cl


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Alkenes Alkenes contain at least one double bond.

Their molecular formula is CnH2n

The double-bonded carbons have trigonal planar

geometries.

An expanded structure for ethene, the simplest alkene,is shown below:

C C

H

H116.6o

H

H121.7o


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Alkenes (II)Note that there is no rotation around a double bond, in

contrast to single bonds. This factor leads to thepossibility ofcis-trans, or geometric, isomerism. When

atoms are bonded to double-bonded carbons, they are

constrained to remain in the same position. For

example, two kinds of 2-butene exist as is shown below:

C CCH3

H

CH3

H

C CH

CH3

CH3

Hcis-2-butene trans-2-butene

CH3 groups are cis, or

same side of double bond

CH3 groups are trans, or

opposite one another


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Alkene Nomenclature

The double bond plays a prominent rolein alkene nomenclature. Despite

whatever else is present, the carbon

chain is numbered from whichever endis closest to the double bond.

When a double bond is present, the

name ending is changed from -ane to-ene.


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Alkene Nomenclature (II)

Example 1:

C CCH2CH3

H

CH3

H

This compound is called 2-pentene, or more correctly,

c is-2-pentene, since the continuing carbon chains are

situated on the same side of the double bond.

Generally, if sufficient structure information is provided,

you should assign a cis or trans designation to the name


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Alkene Nomenclature (III)

Other rules we have learned also apply to alkenes, except

that the double bond dictates the direction of chain

numbering. For example:

C CH

CH2CHCH3

CH3

CH2

H

trans-6-bromo-3-heptene

Br

Note that the double bond determines chain

numbering, not the bromo group.


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Alkene Nomenclature (IV)

Provide a complete, correct name for the following:

C CH

CH2CCH3CH3

H

Br

CH3


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Alkene Nomenclature (IV)

Provide a complete, correct name for the following:

C CH

CH2CCH3CH3

H

Br

CH3

cis-5-bromo-5-methyl-2-hexene


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CycloalkenesCycloalkenes, which have a molecular formula of C

n

H2n-2

,

share many characteristics of alkenes, however, in order to

form rings, the double bond generally must be in the cis form.

When naming a cycloalkene, it is understood that the double-

bonded carbons are numbered 1 and 2. Examples:

Cyclohexene

3-

methylcyclohexeneCH

3CH3


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Alkynes

Hydrocarbons containing a triple bond are

called alkynes, and have molecular

formulas of CnH2n-2.

The triple bonded carbons exhibit linear

geometries, with bond angles of 180o.

This geometry prevents them from

forming rings.

Nomenclature for alkynes is completely

analogous to the method for alkenes.


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Aromatic Hydrocarbons

Aromatic hydrocarbons are ring structures

with multiple double bonds. The doublebonds are conjugated, alternating doubleand single bonds.

Aromatic hydrocarbons have molecularformulas approaching CnHn.

These structures are planar, with all ringcarbons exhibiting a trigonal planargeometry, and a high degree of resonance.

A number of aromatics are notoriouscarcinogens


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Aromatic Nomenclature

NH2 CH3 OHOH

Benzene Aniline Toluene Phenol

NH2 CH3 OHOH

Benzoic

Acid

COOH


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Aromatic Nomenclature (II)

Nomenclature for aromatics is performed much like othercyclic compounds.

If only one substituent is present, numbering is unnecessary

If one of the common names, such as phenol, is used, it is

understood that the substituent is on carbon 1. Othersubstituents present are numbered or given a special

designation used in aromatic chemistry.

In general, substituents are numbered by counting

clockwise or counterclockwise to produce the lowest

numbering pattern.


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Aromatic Nomenclature (II)

Nomenclature for aromatics is performed much like

other cyclic compounds.

If only one substituent is present, numbering isunnecessary

If one of the common names, such as phenol, is used, it

is understood that the substituent is on carbon 1. Othersubstituents present are either numbered or given aspecial designation used in aromatic chemistry.

1-2 substitution is called ortho

1-3 substitution is called meta

1-4 substitution is called para


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Aromatic Nomenclature (III)

Examples:

3-chloroaniline

ormeta-chloroaniline

4-bromotoluene

orpara-bromotoluene

2,4-dimethylphenol

NH2

Cl

NH2

Cl

CH3

Br

CH3

Br

OH

CH3

CH3

CH3

CH3

OH


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Hydrocarbon Chemistry

Hydrocarbons are generally derived

from natural sources, particularlypetroleum.

The most plentiful compounds in

petroleum are alkanes. A number of reactions can be used to

convert one type of hydrocarbon intoanother.

Organic compounds are much morereactive when heteroatoms, N and O,are present.


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Alkanes

Alkanes are generally considered to beunreactive.

They are commonly combusted as

gasoline, diesel, kerosene, etc. They can also be reacted with the

halogens, e.g. Cl2 and Br2, to form

halogenated forms. The halogenated forms can be used to

produce other compounds.


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Alkenes

The double bond in alkenes makes them much

more reactive than alkanes.

The pi electrons in the double bond are relatively

loosely held, and the double bond is subject to

attack by substances attracted to negative charge(electrophiles).

Generally, substances are added to the doubly

bonded carbons, and the double bond is lost.

Ethylene and propylene are heavily used toproduce polymers polyethylene and

polypropylene.


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Alkynes

Alkynes have two pi bonds, and reactmuch like alkenes, except that

stoichiometrically they tend to react twice

as much.

The most common alkyne, acetylene, is

capable of participating in unusual

reactions with strong bases, and it

combusts at very high temperature, whichmakes it ideal for welding torches.


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Aromatic Compounds

Although aromatic compounds containdouble bonds, they do not react likealkenes, because the loss of double bondswould eliminate their stabilizing resonance.

Instead, aromatic compounds tend toundergo substitution reactions, where othersubstances replace hydrogen atoms on thering carbons.

A number of aromatic hydrocarbons areproduced as pollutants when otherhydrocarbons are burned.


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Alcohols

When a carbon atom is bonded to an -O-Hgroup, often designated as R-O-H, where Ris used as a general designation for a carbongroup, the molecule is called an alcohol.

The -OH group is very polar, and most smallalcohols have high boiling points and goodwater solubility.

Besides simple alcohols, alcohols are foundbiologically in carbohydrates and variousmetabolites.


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Alcohol Nomenclature

Alcohols often have common trivial names,

but IUPAC nomenclature rules suggest that

the alcohol name contain the -ol suffix.

The alcohol group is considered higher

priority than any carbon-containing group,and the chain should be numbered from

whichever end is closest to the alcohol

group. Other groups are named and numbered as

shown previously


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Alcohol Nomenclature (II)

Examples:

CH3CH2-OHEthyl alcohol (trivial name)

Ethanol (IUPAC name)

CH3CHCH2CHCH3

Cl OH

4-chloro-2-pentanol

CH3

OH

CH2CH2CHCH2CHCH3

CH3Br OH6-bromo-4-methyl-2-hexanol

3-methylcyclohexanol


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Ethers

Another oxygen-containing functional group

is the ether. The ether group, sometimesdesignated as R1-O-R2, contains an oxygenbridge between two carbon atoms.

Ethers, unlike alcohols, do not participate inhydrogen bonds, and are not consideredpolar.

Ethers, which are important medical andindustrial chemicals, are not commonlyfound naturally in biological systems.


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Ether Nomenclature

Although IUPAC recommends a methodfor naming ethers, we will only focus on

a trivial method that is in common use.

With this method, the two carbon-containing groups connected by the

oxygen are listed alphabetically,

followed by the name ether.

( )


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Ether Nomenclature (II)

Examples:

CH3-O-CH2CH3 Ethyl methyl ether

CH3CH2-O-CH2CH3 Diethyl ether

O

CH3 Cyclohexyl methyl ether

Diethyl ether was used for years as an anesthetic until it

was replaced due to safety considerations.

C b l G


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Carbonyl Groups

The carbonyl group contains a carbon-

oxygen double bond. This functional group

can be found in the interior of a carbon

chain, where it is called a ketone, or on a

terminal carbon, where it called an aldehyde.

A commonly used representations of

ketones and aldehydes look as follows:

R1-C-R2

O||

R-C-H or RCHO

O||

Ketone Aldehyde

C b l G (II)


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Carbonyl Groups (II)

Carbonyl groups, particularly aldehydes, are veryreactive, and appear in many biologicalcompounds.

Like alcohols, carbonyl groups are found incarbohydrates, and they are observed duringmany metabolic processes

These compounds are moderately polar, and thesmaller ketones and aldehydes are water soluble.

A number of ketones have common names, suchas acetone and methyl ethyl ketone (MEK), andare widely used industrial solvents.

K t N l t


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Ketone Nomenclature

When a ketone is present in a compound, it

is considered higher priority than anything

discussed thus far, and the chain is

numbered from whichever end is closest to

the ketone. If an alcohol is also present, itis given a number and is called a hydroxy

group.

When a ketone is present, the suffix for thename is changed to -one.

K t N l t (II)


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Ketone Nomenclature (II)

Examples:

Acetone (trivial name)

2-propanone (IUPAC name)

CH3CCH2CH3

O||

CH3CCH3

O||

Methyl ethyl ketone (trivial name)

2-butanone (IUPAC name)

CH3CHCCH2CHCH3

O||

OH|

CH3|

5-hydroxy-2-methyl-3-hexanone

Ald h d N l t


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Aldehyde Nomenclature When an aldehyde is present in a compound, it is

considered higher priority than anything discussedthus far, and the chain is numbered from aldehyde

end. The aldhyde group is understood to be on the

terminal carbon, so it needs no number. If ketones

are also present, they are called oxo groups andare given a number.

When an aldehyde is present, the suffix of the name

is changed to -al. Remember, aldehydes can be represented as:

R-C-H or RCHO

O||

Ald h d N l t (II)


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Aldehyde Nomenclature (II)Examples:

CH3C-H

O|| Formaldehyde (trivial name)

Methanal (IUPAC name)

CH3CCH2CHO

O||3-oxobutanal

CH3CHCCH2CHCHO

O||

OH|

Cl|

5-chloro-2-hydroxy-4-oxohexanal

C b li A id


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Carboxylic Acids Carboxylic acids have the generalized formula:

The carboxyl name is a contraction of carbonyland hydroxyl group names, which are bothpresent.

The hydrogen on the hydroxyl group is acidic, andcarboxylic acids are notable for their acidicbehavior.

Carboxylic acids are found in many biologicalcompounds, most notably amino acids.

R-C-OH or RCOOH

O||

C b li A id N l t


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Carboxylic Acid Nomenclature

The carboxylic acid structure requires that this

functional group be on a terminal carbon. The carboxyl group has higher priority than

any other functional group, and if it is present,

it is understood to be on carbon number 1,and the chain is numbered away from it.

Other groups present are numberedappropriately, and the names suffix is

changed to -oic, followed by the word acid.

There are many trivial names, such as aceticacid that are commonly used.

C b li A id N l t (II)


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Carboxylic Acid Nomenclature (II)Examples:

CH3C-OH

O||

Acetic acid (trivial name)

Ethanoic acid (IUPAC name)

CH2CH2CH2COOH

OH|

Gamma-hydroxybutyric acid or GHB(trivial name)

4-hydroxybutanoic acid

CH3CHCCH2CHCOOH

Cl|

CH3|

Cl|

4,5-dichloro-2-methylhexanoic acid

A i


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Amines

Amines act as bases in organic chemistry. They contain the amino functional group:

R-NH2

These compounds are notable for theirbasic nature and strong odors.

Nitrogen-containing compounds, or amines,are found in a variety of biological

compounds including amino acids andnucleic acids.

A i N l t


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Amine Nomenclature

Amines are commonly named by referring to the alkyl

group attached to them, followed by the word amine.

In IUPAC, or systematic, nomenclature, the amine is

numbered from which ever end of the chain is closest.

The final e of the name is replaced by the suffix -amine. If a higher priority group is present, the amine is called an

amino group and given a number. All of the oxygen-

containing functional groups are considered higher priority.

Finally, though we wont cover them, amines exist wheremore than one carbon group is attached to the nitrogen

atom.

A i N l t (II)


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Amine Nomenclature (II)

Examples:

CH3CHCH3

NH2|

Isopropyl amine (trivial name)

2-propanamine (IUPAC name)

CH3CHCH2CH2-OH

NH2|

3-amino-1-butanol

CH3CHCOOH

NH2|

Alanine (amino acid)

2-aminopropanoic acid

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