Rules for Nomenclature and Alkynes:

 ALKYNES:

Alkynes are unsaturated hydrocarbons which contain a carbon-carbon triple bond. 

They can be represented by the general formula CnH2n-2. 

The first and most important member of this series is acetylene and hence these are generally called acetylenes. 

The carbon-carbon triple bond is therefore called acetylenic bond.

Rules for Nomenclature and Alkynes: ( IUPAC)

   Following are the some rules 

1. Select  longest continuous chain of carbon          atom containing triple bond.

2. Name of compound must end on yne .

      E.g ethyne propyne etc

3.Give triple bond  least possible number.

4.Substiutnt name is always written before              parent name.

5.Position of triple bond must be mentioned.

6.Position of substituent must be mentioned         before name

7.If more then one similar type of substituents are present we will use the term di For 2 Tri for 3

 Tetra  for 4

8.If different type of substituents are present we  will follow alphabatical order .

9.If more then one triple bonds are present we will use the term diyne for 2triple bonds and triyne for 3 triple bonds.

Examples:

H-C≡C-H                Ethyne 

H–C≡C-CH3          Propyne

CH3-CH2-CH2-C≡C-CH3  2-Hexyne

H-C≡C-CH2-CH2-CH2-CH2-CH3 1-Heptyne

H-C≡C-C≡C-H 1,3-Butadiyne

Rules for Nomenclature and Alkenes: ( IUPAC)

 ALKENES:

Alkenes are unsaturated hydrocarbons which contain a carbon-carbon double bond. 

They can be represented by the general formula CnH2n. 

Why alkenes are called olefins?

They are also known as 'olefins', derived from Latin word 'oleum' meaning 'oil' and 'ficare' meaning 'to form', because their lower members form oily layer on treatment with chlorine and bromine.

Rules for Nomenclature and Alkenes: ( IUPAC)

Following are the some rules 

1. Select  longest continuous chain of carbon          atom as a parent chain containing double bond.

2. Name of compound must end on ene .

      E.g ethene propene etc

3.Give double bond  least possible number.

4.Substiutnt name is always written before              parent name.

5.Position of double bond must be mentioned.

6.Position of substituent must be mentioned         before name

7.If more then one similar type of substituents are present we will use the term di For 2 Tri for 3

 Tetra  for 4

8.If different type of substituents are present          we  will follow alphabatical order .

9.If more then one double bonds are present we will use the term diene for 2 double bonds and triene for 3 double bonds

Examples      

            1      2      3      4     5     6                                         CH3-CH=CH-CH2-CH2-CH3  2- Hexene

                 CH3                                                                               |                                                                    CH3-CH=C-CH-CH2-CH3 

          3-Methyl-2-Hexene

 1      2      3      4     5     6

CH3-CH=CH-CH=CH-CH3  2,4-Hexadiene

Rules of Nomenclature and Alkanes

  

Hydrocarbon:

It is type of saturated hydrocarbon containing carbon -carbon single bond .

ALKANES:

Alkanes are open chain saturated hydrocarbons containing single bond. 

which can be represented by the general formula CnH2n+2 (where'n'is the number of carbon atoms),

while cyclo alkanes are cyclic saturated hydrocarbons represented by the general formula CnH2n . 

It is to be noted from the general formula of cycloalkanes, that there are two hydrogen atoms less than the corresponding alkanes. 

In cycloalkanes, two carbon atoms of the molecule utilize one of their valency in forming bonds with other carbon atoms for formation of cyclic ring.

Following are the some rules 

Rules for Nomenclature and Alkanes: ( IUPAC)

Following are the some rules 

1. Select  longest continuous chain of carbon          atom as a parent chain.

2. Name of compound must end on ane .

E.g methane ethane propane etc

3.Give substituent least possible number.

4.Substiutnt name is always written before              parent name.

5.Position of substituent must be mentioned.

 6.If more then one similar type of substituents are present we will use the term di For 2 Tri for 3

Tetra  for 4

7.If different type of substituents are present we will follow alphabatical order .

Examples:

                   CH3                                                                               |                                                              CH3-CH2-CH-CH2-CH2-CH3  3-Methyl hexane

                                 CH3  CH3                                                                   |     |                                                                CH3-CH-CH-CH2-CH2-CH3 

          2,3-Dimethyl hexane

CHELATING LIGANDS

 CHELATING LIGANDS:

"The bonding of a polypeptide ligand to a metal ion through more than one site is called chelating ligand."

These ligands produce a ring like structure called chelate. 

The polydentate ligand is called a chelating agent, 

The process of chelate formation is known as chelation and the compounds formed are called as chelate compounds. 

Chelation increases the stability of complex. For example, ethylene diamine acts as a bidentate chelating ligand.

HOMOLOGOUS SERIES:

 HOMOLOGOUS SERIES:

"A series of organic compound in which each member is different from the next member by a methylene (-CH2-) group is called homologous series".

All the members that differ from each other by methylene group, are called homologues. Each class of organic compounds has its own homologous series which can be represented by a general formula. For example, alkanes (saturated hydrocarbons) can be represented by a series of compounds. It can be represented by a general formula CnH2n+2 where 'n' shows the number of carbon atoms in the corresponding alkane.

As it is clear from alkane homologous series that each member is different from the adjacent member by CH3. Similarly, this series can be expanded beyond C10 to higher alkanes. Similar homologous series can be developed for alkenes, alkynes, alcohols, ethers, amines, carboxylic acids, carbonyl compounds etc.

CHARACTERISTICS OF HOMOLOGOUS SERIES:

*Each class of organic compounds has its own homologous series having same  general formula.

*All the members of homologous series have similar chemical properties.

* They have same general methods of preparation similar structural features.

*They have same functional group.

*The physical properties like melting point, boiling point, densities etc, increase down the series due to increase in their molecular masses.

For Example lets see homology in alcohol.

CH3CH2OH                               Ehtyl alcohol

CH3CH2CH2OH                        Propyl alcohol

CH3CH2CH2CH2OH                 Butyl alcohol 

CH3CH2CH2CH2CH2OH          Pentyl Alcohol

CH3CH2CH2CH2CH2CH2OH  Hexyl alcohol

Consider another example:

CH3CH2Cl                               Ehtyl Chloride

CH3CH2CH2Cl                  Propyl Chloride

CH3CH2CH2CH2Cl              Butyl Chloride

CH3CH2CH2CH2CH2Cl        Pentyl Chloride

CH3CH2CH2CH2CH2CH2Cl  Hexyl Chloride

NUCLEAR MAGNETIC RESONANCE (NMR) SPECTROSCOPY

NUCLEAR MAGNETIC RESONANCE (NMR) SPECTROSCOPY:

Nuclear magnetic resonance spectroscopy (NMR) is the most powerful tool available for organic structure determination. Like infrared spectroscopy, NMR can be used with a very small amount of sample, and it doesn't harm the sample. The NMR spectrum provides a great deal of information about the structure of the compound, and many structures can be determined using only the NMR spectrum. More commonly, however, NMR spectroscopy is used in conjunction with other forms of spectroscopy and chemical analysis to determine the structures of complicated organic molecules

MAGNETIC SHIELDING BY ELECTRONS:

Protons in a molecule are surrounded by electrons and exist in slightly different electronic (magnetic) environments from one another. The electron densities vary from one proton to another. Thus, the net field felt by a proton in a molecule will always be less than the applied field and the proton is said to be shielded. All of the protons of a molecule are shielded from the applied field by the electrons, but some are less shielded than others, because they may have less surrounding electron cloud and termed as deshielded protons. Deshielded protons are generally in vicinity of electronegative atoms in a molecule. More shielded protons absorb low radio-frequency radiations and their signals appear to the right side of spectrum, upfield region; while deshielded protons absorb high radio-frequency radiations and their signals therefore, appear at the left side of spectrum, downfield region.

PESTICIDES:

 PESTICIDES:

Pests harm crops and transmit diseases both to human and animals. Pesticides are the substances that can directly kill an unwanted organism or otherwise control by interfering with its reproduction process. The current ability to produce large amounts of food on relatively small amount of land had been made possible around the world by use of pesticides. At present more than ten thousand different types of synthetic organic pesticides have been formulated. They are broadly classified into several principal types according to their general chemical nature. The most important and widely used pesticides are insecticides (which kill insects), herbicides (which kill undesired plants) and fungicides (which control the growth of fungus on the plant).

The use of various pesticides also helped in the eradication of diseases such as malaria, yellow fever, bubionic plague and sleeping sickness.

Wide spread use of pesticides for getting greater crop yields if not properly checked and controlled has associated risks of contaminating the soil, plants and the water. The drainage water from the agricultural land mostly contains pesticides. Therefore if the use of any type of pesticide is not properly controlled it enters through various roots i.e., agricultural food products and drinking water into the food chain and thus pose serious health problems to both human beings and animals.