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ORGANIC CHEMISTRY-SEM-1H

01-ORGANIC CHEMISTRY�AN INTRODUCTION

DR. KARTIK KUMAR NANDI

ASSOCIATE PROFESSOR OF CHEMISTRY

DEPARTMENT OF CHEMISTRY

BRAHMANANDA KESHAB CHANDRA COLLEGE

KOLKATA – 700108

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E-Mail: kmnandi@gmail.com

Mob.No. : 9433425083

Website:https://sites.google.com/view/kartiknandi

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Organic Chemistry

  • > 95% of All Known Compounds Composed of Carbon
  • Organic Chemistry Crucial to Our Way of Life: Clothing, Materials (Polymers), Petroleum, Medicine, OUR BODIES , ...
  • > 50% of Chemists Are Organic

Chemistry is the study of matter, and all matters are made up of atoms.

Organic chemistry is the study of the structure, properties, composition, mechanisms, and reactions of organic compounds

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Organic Chemistry: What is it?

  • 1780: Organic compounds very complex and only obtained from living sources (vitalism) Vitalism: Belief that a "magic" vital force, present in plants and animals, is necessary for the synthesis of organic compounds.
  • 1789: Antoine Laurent Lavoisier observed that organic compounds are composed primarily of carbon and hydrogen.
  • 1828: Friedrich Wohler synthesized an organic compound (urea) from inorganic compounds. (lead cyanate and ammonium hydroxide).

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Modern organic chemistry is the chemistry of carbon compounds.

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�Organic chemistry is a growing subset of chemistry. �

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Organic Chemistry

  • STRUCTURE;

Determining the Way in Which Atoms Are Put Together in Space to Form Complex Molecules

  • MECHANISM;

Understanding the Reactivity of Molecules: How and Why Chemical Reactions Take Place

  • SYNTHESIS;

Building Complex Molecules From Simple Molecules Using Chemical Reactions

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Why Carbon?

  • Carbon forms a variety of strong covalent bonds to itself and other atoms.
  • This allows organic compounds to be structurally diverse.

Carbohydrates /Amino Acids /DNA Bases /Hormones , etc.

  • Over 10 million compounds have been identified
    • about 1000 new ones are identified each day!
  • Why Does Carbon Bond in This Way?

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Why Carbon?

# C is a small atom, it forms single, double, and triple bonds,

# C is intermediate in electronegativity (2.5)

it forms strong bonds with C, H, O, N,

# C has a special property; CATENATION: Catenation is the linkage of atoms of the same element into longer chains.

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This is the reason for the presence of the vast number of organic compounds in nature.

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Rules for Drawing

• Bonds are represented by lines

(one line = two shared electrons)

• Do not draw carbon or hydrogen atoms, except at termini (for aesthetics)

• Assume carbon atoms are at ends of lines and where they meet

• Assume enough C–H bonds to give each carbon atom four bonds (an octet)

• Draw hetero-atoms and attached hydrogen atoms (N,O,S,P,F,Cl,Br,I, etc.)

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Molecules Are Not Flat!

  • Methane, Ethane, Propane
  • Cyclopropane, Cyclohexane, Benzene

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Why Does Carbon Bond in This Way?�----- Chemical bonding -----

  • Lewis Bonding Theory ;Atoms transfer or share electrons to gain a filled valence shell of electrons.
  • A. IONIC BONDING : Between atoms of widely different electronegativity (ΔEN>2); usually a metal and a non-metal; atoms held together by electrostatic attraction, not electron sharing
  • B. COVALENT BONDING (Electron Sharing)

Very important in organic molecules! • Between atoms of similar electronegativity; usually non-metallic . [LONE PAIR: unshared electron pair; non-bonding pair of electrons ]

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SYLLABUS: Major (Core Course) for HONOURS in CHEMISTRY

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SEMESTER-I

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DS-1: (Credits: Theory-03, Practicals-02)

Theory: 45 Lectures Marks: 50: All Units carry equal marks

Unit-2: Basics of Organic chemistry

(15 Lectures)

Nomenclature for acyclic compounds only (trivial and IUPAC), DBE, hybridization(sp", n= 1,2,3) of C, N, O, halogens, bond distance, bond angles, VSEPR, shapes of molecules, inductive and field effects, bond energy, bond polarity and polarisability, dipole moment, resonance, resonance energy, steric inhibition of resonance, hyperconjugation, π-M.O diagrams of ethylene, butadiene, 1,3,5- hexatriene, allyl cation, allyl anion, allyl radical, HOMO and LUMO in ground and excited states, orbital pictures of allene, carbene(singlet and triplet), vinyl cyanide, Huckel's rule for aromaticity and antiaromaticity (neutral systems 4,6,8,10 annulene, charged systems 3,4,5,7 rings, Frost-diagram, melting point, boiling point, heat of hydrogenation, heat of combustion, hydrogen bonding (intra- and inter-molecular), crown-ether, concepts of acidity, basicity. Reaction intermediate, carbocation, carbanion, radicals, carbene & stability and generation.

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BOOKS FOR ORG-CHEMISTRY I[H]

  • TEXT BOOKS FOR B.Sc. Hons COURSES:
  • A Guidebook to Mechanism in Organic Chemistry by Sykes, Prentice Hall.
  • Organic Chemistry --- [Vol-I & II] I. L. Finar.
  • Organic Chemistry ----- By Morrison & Boyd
  • Organic Chemistry ----- Pathak & Saha [1-3]
  • Organic Chemistry-A Modern Approach-N.Tewari [1-3]
  • Basic Stereochemistry of Organic Molecules --- by S. Sengupta.

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  • Nasipuri, D. Stereochemistry of Organic Compounds,Wiley Eastern Limited .
  • Stereochemistry, Oxford Chemistry Primer, Oxford University Press, 2005
  • Organic ChemistryOrganic Chemistry by Clayden, Greeves and Warren, Oxford University Press, 2012 (ISBN 978-0199270293)
  • Fleming, I. Molecular Orbitals and Organic Chemical Reactions, Reference/Student Edition, Wiley, 2009.

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Learning Resources

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