Organic chemistry General outline

BOND POLARIZATION Electron shifts in σ- bonds Permanent sigma bond polarization : static inductive effect constant bond polarity C O 2. Temporary sigma bond polarization : ( dipole – induced dipole) Dynamic inductive effect temporary polarity

electron interactions in p-bonds BOND POLARIZATION electron interactions in p-bonds (tautomer effect) 1. Static conjugation effect: C=O σ+ σ- 2. Dynamic conjugation effect: C=C σ- σ+ - +

Formulas of organic chemistry Empirical formula : the atomic composition of the compound The ratio of the atoms only. not informatic! e.g. C2H6O 2. Condensed formula: contains the main structure details CH3-O-CH3 or CH3-CH2-OH 3. Expanded formula or full formula: shows all of the structure details

Structures of organic compounds linear/branched Cyclic/aromatic Saturated Unsaturated II. We can distinguish the substituent and non-substituent part Substituent: everything (a group or an atom) which is attached to the carbon, except Hydrogen Non-substituent: all C and H atoms substituted compounds (the H and/or C atoms are substituted by hetero atoms - like O, S, N, halogens or metals

Structures of organic compounds III. Functional groups In organic chemistry, functional groups (or moieties) are specific groups of atoms. Functional groups are attached to the carbon backbone of organic molecules. They determine the characteristics and chemical reactivity of molecules. Functional groups are less stable than the carbon backbone and are likely to participate in chemical reactions. - The same functional group will undergo the same or similar chemical reaction(s) regardless of the size of the molecule it is a part of.

Structures of organic compounds III. Functional groups Halogen atom containing compounds Oxygen containing compounds Alcohols : hydroxyl group –OH Ethers : ether group : C-O-C Aldehydes : aldehyde group (terminal carbonyl group): -HC=O Ketones: keto group( carbonyl group ) Carboxylic acids: carboxyl group

characterizes the following types of compounds A carbonyl group (C=O) characterizes the following types of compounds Compound: Aldehyde Ketone Carboxylic acid Ester Structure:                                         General formula: RCHO RCOR' RCOOH RCOOR'

3. Nitrogen containing compounds Amines: R-NH2 Nitro compounds 4. Sulfur containing compounds Thiols:

IV. Isomeres Isomeric form: identical atomic composition, diffrent structure Geometric isomerism e.g. cis-trans isomerism optical isomerism …. 2. Functional isomerism

Nomenclatures of organic compounds Trivial names 2. Official names, given by IUPAC – rule of numbering C atoms - rule of naming the isomer and the normal forms e.g. : alcohol = ethanol propanol = propane-1-ol acetic acid = etanoic acid aceton = propanon or propan-2-one 

Reaction types in organic chemistry Substitution Elimination Addition 1. Substitution Replacement of an atom ( mostly H) CH4 + Cl2 = CH3Cl + HCl Chloromethane or Methyl chloride CH3-CH2-Cl + NaOH CH3-CH2-OH + NaCl Sigma bond reaction

2. Elimination - withdrawal of a molecule from the compound a. intramolecular e.g. CH3-CH2-CH2-Cl CH3-CH=CH2 + HCl Pi-bond forms b. intermolecular = condensation e.g. CH3-OH + OH-CH3 CH3-O-CH3 + H2O No pi-bond forms Dimethyl ether

3. Addition the opposite to elimination two or more molecules combine to form a larger one CH2=CH2 + H2O CH3-CH2-OH ethene CH2=CH2 + Cl2 Cl-CH2-CH2-Cl ethene Pi bond is eliminated

Reaction types - Only 3 reaction types : substitution, elimination, addition - These 3 main reaction types include all other reactions e.g. oxidation, hydrolysis, condensation……. e.g. oxidation of the methane 1 2 3 4 Methane methanol formaldehide formic acid carbon dioxide Oxidation – substitution Elimination of H2 Substitution

Reaction mechanism 2 reaction mechanism in organic chemistry 1. Ionic mechanism a. Nucleophylic b. electrophylic 2. Radical mechanism The reaction mechanism is definite by the nature of the attacking agent

Reaction mechanism 1.a Nucleophylic substitution: SN Static inductiv effect C-O

Reaction mechanism 1.b Electrophylic addition: AdE CH2=CH2 + Br2 CH2Br-CH2Br 1,2 dibromo ethane ethene Unequal spliting of the Br-Br bond – heterolytic cleavage results ions

Reaction mechanism 2. Radical mechanism radical :atom or molecule with unpaired electron the attacking agent contains a free radical that was formed as the result of homolytic bond cleavage In organic chemistry during the reactions we get more than one product Redical mechanisms give mixture of products as well

Reaction mechanism 2. Radical mechanism Radical chain reaction 2 ways for spliting chemical bonds: Unequal spliting of the bond – heterolytic cleavage the result is ions 2. Equal spliting – homolytic cleavage the result is radicals