Introduction to Organic Chemistry Bettelheim, Brown, Campbell and Farrell Chapter 10

Organic Chemistry Compounds that contain carbon –Other elements: H, O, N, Cl, F, Br, I, P, S Most compounds known are organic (> 85 %) NOT just from living systems (biochemistry) Wohler synthesized urea from inorganic compounds Vital Force Theory disprove

Biochemistry: Chemistry of Living Systems Biochemical MoleculesBiochemical Molecules –Carbohydrates –Lipids –Proteins and enzymes –Nucleic acids –Hormones –Vitamins –Almost all chemicals in living systems are organic compounds Biochemical molecules are BIG organic molecules

Organic vs. Inorganic Compounds

Table 11.1

Organic Structures & Formulas Molecular Formula: Molecular Formula: shows only the number of each type of atom Structural Formula: Structural Formula: shows atoms and the bonds that connect them Lewis Structure: Lewis Structure: shows the atoms, bonds and unshared electron pairs (valence electrons only)

Organic Compounds—Atoms & Bonds For neutral (uncharged) organic compounds –carbon: –carbon: four covalent bonds and no unshared pairs of electrons –hydrogen: –hydrogen: one covalent bond and no unshared pairs of electrons –nitrogen: –nitrogen: three covalent bonds and one unshared pair of electrons –oxygen: –oxygen: two covalent bonds and two unshared pairs of electrons –a halogen: –a halogen: one covalent bond and three unshared pairs of electrons

Number of bonds formed Carbon4 bonds Nitrogen3 bonds Oxygen2 bonds Hydrogen1 bond Halogen1 bond

Organic Structure VSEPR model: VSEPR model: the most common bond angles are 109.5°, 120°, and 180°

Organic Chemistry Chemistry of compounds containing C –Over 95% of known compounds are organic What makes C special? –Forms stable bonds with other C atoms Can form bonds to up to 4 other atoms Can form chains, rings, many shapes –Can form stable bonds with H, O, N, F, Cl, Br, I

Bonding of Carbon C has 4 valence electrons Would expect 2 s and 2 p electrons Actually see 4 “equivalent” bonds for tetrahedral C Explained by “hybrid orbitals”

Methane – Tetrahedral geometry

s and p Orbitals Orbitals have definite shapes and orientations in space (insert Fig 2.11 of text) (if it will not all fit on one screen, put part (a) on one screen and part (b) on the next)

Hybrid Orbitals—s and p combinations

Functional Groups Part of an organic molecule that undergoes chemical reaction –“Business end” of molecule Functional groups are important –Undergo the same types of chemical reactions no matter in which molecule they are found –Determine chemical and physical properties of compound –Basis for organizing organic compounds into families –Used in naming organic compounds

Some Important Functional Groups

Alcohols Alcohol:Alcohol: contains an OH (hydroxyl) group bonded to a tetrahedral carbon atom –may be primary (1°), secondary (2°), or tertiary (3°)

Amines Amine:amino groupAmine: a compound containing an amino group –the amino group may be primary (1°), secondary (2°), or tertiary (3°)

Aldehydes and Ketones C=O (carbonyl) groupBoth contain a C=O (carbonyl) group –aldehyde: –aldehyde: contains a carbonyl group bonded to a hydrogen; in formaldehyde, the simplest aldehyde, the carbonyl group is bonded to two hydrogens –ketone: –ketone: contains a carbonyl group bonded to two carbon atoms

Carboxylic Acids Carboxylic acid: a compound containing carboxylCarboxylic acid: a compound containing a - COOH (carboxyl: carbonyl + hydroxyl) group –in a condensed structural formula, a carboxyl group may also be written -CO 2 H.

Biochemical molecules –are just BIG organic molecules –react like organic molecules Need to understand organic chemistry in order to understand and appreciate biochemistry