Organic ChemistryChapter 1—An Introduction to Organic

Chemistry and Carbon

Introduction to Organic Chemistry

Organic chemistry is the study of carbon-containing compounds(especially compounds containing C-C

bonds) The field of organic chemistry is very

important for a wide variety of reasons.A huge number of carbon-containing

compounds are known. More than 16 million known compounds About 90% of new compounds made each

year contain carbon

Introduction to Organic Chemistry

Most of the advances in the pharmaceutical industry are based on a knowledge of organic chemistry.Many drugs are organic compounds

Life as we know it is based on organic chemistry.Most biologically important compounds contain

carbon: DNA, RNA proteins carbohydrates

Organic Compounds

Organic compounds are those compounds found in any organism that is living or was once living containing carbon. Compounds lacking carbon and not from living organisms referred to as “inorganic”.

Organic Compounds

Organic compounds are those compounds found in any organism that is living or was once living containing carbon.

Carbon – The Element of Life

Carbon’s unique atomic structure allows it to covalently bond with up to four other atoms

Carbon is the simplest element on the periodic table that also has four valence electrons

Carbon is neither electronegative nor electropositive

Drawings of carbon and it’s bonding ability:

Carbon—The Element of Life

Most organic compounds have a “skeleton” that is composed of C-C bonds.

The C-C bonds may be single bonds, double bonds, or triple bonds.

The “skeleton” of an organic compound has H’s attached to it.other “heteroatoms” like O, halogens or N

may be present as well

Carbon

The number of bonds formed by C in an organic compound is determined by the electron configuration of C.

Carbon has four valence electrons:1s22s22p2

Carbon Carbon generally forms 4 equivalent

bonds. The formation of four equivalent bonds

is best explained using the concept of hybrid orbitals.

Hybrid orbitals

Hybrid Orbitals & Carbon

When C forms four single bonds:sp3 hybrid orbitals are involved tetrahedral

geometry

When C forms a double bond:sp2 hybrid orbitals are used trigonal planar

geometry

When C forms a triple bond:sp hybrid orbitals are used linear geometry

Bonding in Organic Compounds

Organic compounds contain not only C-C bonds but also C-H bonds.

C-C and C-H bonds tend to be non-polar because there is a small difference in electronegativites

Most (but not all) organic compounds are relatively non-polar

generally not very soluble in water

Structural Formulas

When we write a simple chemical formula, such as CH4, we are actually writing what we call a molecular formula

Molecular Formulas – show the atoms and the number of atoms involved in a molecule but nothing else

In organic chemistry, it is often more useful to show structural formulas instead

Structural Formulas – show each type of atom and how they are arranged in a molecule

Structural Formulas

Molecular Formula Structural Formula 3-D Structure

CH4H -

H

H

HC -

Isomers

Structural formulas are important in organic chemistry because of isomers

Isomers are two compounds with the SAME MOLECULAR formulas but different structural formulas

-- they have different chemical and physical properties

C3H8O

Types of Organic Compounds

The simplest organic compounds are the hydrocarbons:organic compounds that contain only

carbon and hydrogen

four general types:alkanesalkenesalkynesaromatic hydrocarbons

Types of Organic Compounds

Alkanes:hydrocarbons that contain only single bonds

Examples:Methane CH4

Ethane C2H6

Alkenes:hydrocarbons that contain a C = C double

bondH2C = CH2 (ethylene)

Types of Organic Compounds

Alkynes:hydrocarbons that contain a C C triple

bondH – C C – H (acetylene)

There are others to follow but these are the first three simplest organic molecules.

Organic compounds that are soluble in polar solvents such as water generally have a polar functional group present in the molecule.An atom or group of atoms that influences the way the molecule functions, reacts or behaves.

An atom or group of atoms in a molecule that undergoes predictable chemical reactions

The center of reactivity in an organic molecule

Functional Groups

Functional GroupsSince functional groups are responsible for the many of the chemical and physical properties of organic compounds, we often classify and study organic compounds by the type of functional group present.Functional

Group Type of

Compound

Example

C = C alkene H2C = CH2

C C alkyne HC CH

C – O – H alcohol CH3OH

C – O – C ether CH3CH2OCH2CH3

C – N amine CH3NHCH3

Functional Groups

Functional Group

Type of Compound

Example

O C – H

aldehyde

O CH3C – H

O C – C – C

ketone

O

CH3 – C – CH3

Functional GroupsFunctional

GroupType of

Compound Example

O

C – O – HCarboxylic

acid

O

CH3C – O – H

O

C – O – C ester

O

CH3C – O – CH2CH3

Functional Groups

Example: Name the functional groups that are present in the following compounds: CH3CH2OH

O

H2C = CHCOH

CH3CH2NCH3

CH3

Major Classifications

1)Acyclic—contains no rings in the structure2)Carbocyclic—contains at least one ring only made up of carbon3)Heterocyclic—contains at least one ring that has an element other than carbon in it

acyclic

carbocyclic

heterocyclic