Essay On Isomerism In An Organic Chemisrty
In his book, The Periodic Kingdom: A Journey into the Land of Chemical Elements, Peter Atkins widely explains the mystery behind isomers. Isomerism is the existence of two or more molecules or nuclides that are isomers. Isomers are molecules containing the same atoms but arranged in different ways. These compounds of molecules differ physically, biologically, and chemically, though the atom in them is the same. One compound may have very different usefulness to its isomer. For instance, one may be harmless while the other may be explosive.
One may be a useful drug, while the other may be ineffective. Isomers have some unique qualities that are very important to living organisms. They are also important in various industries such as the pharmaceutical and other chemical industries. An example of an isomer is gasoline and lactic acid. 2. 0 BODY Isomers are either structural isomers, stereo isomers, or nuclear isomers, depending on the difference in arrangement of the molecules. Examples of isomers are ethyl alcohol and dimethyl ether. Both share the simple chemical formula C2H6O.
Although ethyl alcohol and dimethyl ether both contain equal numbers of atoms of the same elements, the atoms within the respective molecules are arranged differently, producing two different compounds. A) Structural isomers These isomers are molecules with the same chemical formula, but atoms connection are different. This produces two very different molecular structures. Gasoline, for instance, contains the compounds pentane, isopentane, and neopentane, structural isomers of C5H12. Each compound has distinct properties. Pentane’s molecules are longer than isopentane’s and neopentane’s.
The entanglement of pentane’s molecules needs higher energy to break them. For this reason, pentane’s boiling point is higher than the others are. (Pentane-36? C, Isopentane-28? C, Neopentane-9. 5? C). B) Stereoisomers These isomers have the same chemical formula and molecular structure, but the atoms are arranged differently within the structure. Two types of stereoisomers are: i) Geometric isomers ii) Optical isomers i) Geometric isomers These are molecules with the same geometry or atomic organization, but the atoms are at different positions in the molecules organization structure.
For example dichloroethane of the formula C2H2Cl2 can have geometric isomers of cis-1,2 dichloroethane, trans-1,2-dichloroethane, and 1,1-dichloroethane. The two carbon in the dichloroethane have a strong chemical bond, a double bond. Chlorine atoms then arrange themselves around the bond in different ways: a cis configuration, a trans configuration, and a 1-1 configuration. The configuration at the top is a cis, one at the middle is the trans, and at the bottom is a 1-1. Geometric isomers can have different properties from one another.
cis isomer of Pt(NH3)2Cl2 is used as an anticancer drug, while the trans isomer Pt(NH3)2Cl2 is ineffective against cancerous tumors. ii) Optical isomers These are isomers that mirror images of each other but cannot be superimposed on each other. An example of an optical isomer is lactic acid. Optical isomers have the same chemical and physical properties except the direction that each isomer turns a plane of polarized light. Optical isomers or enantiomers are different from each other and have different properties. Muscles produce D-lactic acid, while sour milk contains L-lactic acid.
The D-lactic acid causes muscular pains and cramps while the L-lactic acid in milk gives it the sour taste. Optical isomers are mostly found naturally and one enantiomer often occurs than the other. Biocatalysis, a chemical process used by scientists to produce only one enantiomer of an optical isomer at a time is used by pharmaceuticals to produce an HIV treatment called Ziagen. By products of this process are used to make heart drugs. C) Nuclear isomers Nuclear isomers come to be during the rare cases of pure gamma, alpha, and beta emissions. Nuclear isomers have the same atomic and mass numbers, but different nuclear energy content.
The emission of gamma rays accompanies the transition of the higher energy isomer to the lower energy form. An example of isomerism is the isotope protactinium-234, existing in two different energy states with the emission of gamma rays signaling the transition from one to the other. In summary, isomerism is a rare and unique property found in some elements and compounds. Isomers have very different properties thus very different usefulness.
Atkins, P. The Periodic Kingdom: A Journey into the Land of the Chemical Elements. Perseus , 1997.Sample Essay of PaperDon.com