Organic CHEMISTRY I

Page 1Organic Chemistry being the study of Chemistry is the study of substances and their different transformations Page 2 carbon containing substances or compounds.Page 3Page 4Chemistry is IMPORTANT Chemistry is present in all aspects of life: The food we eat. The clothes we wear. Page 5 Medicine. Sports.Organic chemicals are all around us Food Carbohydrates Proteins Lipids Clothing Natural materials: Page 6 Silk, Cotton Synthetic (man-made) materials: Nylon, Terylene Medicine Aspirin, Penicillin, paracetamol OthersPVC, Kerosene, urea, paints, TNTComplex molecules? H H HO H H H H O H H OH Testosterone Page 7 Cholesterol H H O H OH Progesterone H H O H OH O OH CortisoneSome Organic Chemicals are Problematic Freons-responsible for loss of ozone layer Chemical weapons more prevalent Certain insecticides resistant to degradation Page 8 Toxic releases Fossil fuel combustion produces large amounts of CO2 increase in greenhouse effect.The Ozone Layer and CFCs Page 9All these problems are due to chemical reactions of the organic compounds. To solve these problems we have to understand these molecules: How do they react? Page 10 Why do they react like that? How can these properties be modified? To understand these organic molecules we have to understand the smallest unit – the carbon atomPage 11The Carbon Atom C Page 12The Carbon Atom Symbol C Atomic Number 6 Atomic Weight 12.011 Page 13 Oxidation States +2, +4, -4 Electronic Configuration 1s2, 2s2,2p2 State at RT Solid, Nonmetal Melting Point, K 3820 Boiling Point, K 5100Page 14Page 15Page 16Page 17Page 18FULLERENE Page 19Carbon can form different types of bonds C C H C C H HH H H H H Page 20 H ETHYNE ETHANE C C ETHENE H H HWhy can carbon form different bonds? 2s 2 electrons 1s 2 electrons This model does not help in explaining the phenomenon. Page 21 Simplistic Carbon atom 1s2, 2s2, 2p2 2p 2 electrons Explanation found using actual illustration of atomic orbitalsWhat are Atomic Orbitals ØThere is no way of determining the exact location of an electron within an atom. FThere is a definite 3 dimensional area around the Page 22 nucleus within which an electron is most likely to be found.An Atomic Orbital is: q A region of space around the nucleus within which the probability of finding an electron is high (~90%). Page 23 q This region can be calculated using advanced mathematical procedures.Types of Atomic Orbital present in carbon that contain electrons 1s orbital-spherical 2s orbital-spherical Page 24 2p orbitals-lobesP orbital ØThere are three p orbitals-2px, 2py and 2pz Page 25P orbital Page 26Bonding Ø The ground state configuration of carbon is unsuitable for bonding. Ø In the ground state carbon can only form two bonds Page 27 q For “correct” bonding to occur some changes have to be made in the orbitals.Orbital Changes-Excitation Page 28Page 29sp3 hybridized orbital Page 30sp3 hybridized orbital Page 31 S and p orbitals Sp3 orbitalssp3 4 orbitals hybridized orbital All the same shape, size and energy Arranged in a tetrahedral conformation Gives minimum repulsion between orbitals. Angle of 109º from each other Page 32 Can form bonds by overlapping with orbitals of other atoms.Bonding in Methane v CH4 v Alkane (saturated) v Carbon atom is sp3 hybridized Page 33 v Bonds are formed by overlapping of the 4 s orbital of hydrogen with the sp3 orbitals of the carbon atom.Bonding in Methane Overlap of s and sp3 rbitals form sigma (σ) bond. Page 34 Methane has 4 σ bonds Page 35 Note that each bond contains 2 electrons: 1 from s orbital of hydrogen 1 from sp3 orbital of carbonEthane C2H6 CH3-CH3 Alkane (saturated) Page 36 Carbon atom is sp3 hybridized. Differs from methane in that a C-C bond is present.Ethane Page 37Ethane Page 38 Ø Overlap of half-filled sp3 hybrid orbital of one carbon with half-filled sp3 hybrid orbital of another.Ethane There is free rotation around the C-C bond Page 39