Organic Compounds: hydrocarbons and derivatives just C and H C, H, N, O, X, etc Hydrocarbons: just C and H atoms alkane: C-C alkene: C=C alkyne: C≡C H H H H H H C C HCCH H C C H HCC H CC aromatic: H H sp CC 2 H H 3 2 sp sp sp H H 3 Alkanes are saturated: all C atoms are sp , with four bonds to four atoms, CnH2n+2 All other hydrocarbons are unsaturated: multiple bonds or rings, fewer than 2n+2 H atoms Representing Organic Compounds chemical formula CH4 C2H6 C3H8 C4H8 C6H6 condensed CH CH CH CH CH CH CH CH CH=CH structural formula 4 3 3 3 2 3 3 2 2 H H H H H H H H H H H C C structural formula HCH HCC H HCC C H HCC C C H C C H (Lewis) H CC H H H H H H H H H H H line structure ––– Line structure: each C-C bond is a line, H atoms on C are omitted – always four bonds to C! Note: groups can rotate about a C-C single 9 8 bond (σ only), but not a C=C double (σ + π)! same molecule different molecules Isomers Isomers: compounds with the same molecular formula, but different structures • Structural Isomers: isomers that differ in the bonding arrangement and connectivity of atoms. Such isomers can differ in terms of: carbon backbone (skeletal isomers): CH3(CH2)3CH3 CH3CH(CH3)CH2CH3 C(CH3)4 pentane 2-methylbutane 2,2-dimethylpropane OH functional group position OH CH3(CH2)2OH CH3CH(OH)CH3 1-propanol 2-propanol (positional isomers): functional group type CH3CH2OH CH3OCH3 ethanol dimethylether (functional isomers): • Stereoisomers: isomers that have the same connectivity, but differ in the B B spatial arrangement of atoms. There are two classes: D A A D C C • Geometric isomers: stereoisomers that differ CH3 CH3 CH3 H CC CC not in the relative orientation of substituents HHHCH 3 super- B e.g. cis- and trans-alkenes cis-butene trans-butene imposable! C A • Enantiomers (or optical isomers): D stereoisomers that are chiral, non-superimposable on a mirror image (Eğe Ch6) Organic Functional Group List Functional IUPAC Name Compound Prefix/Suffix Example Group (Common Name) R-H alkane -ane CH3CH3 ethane CC alkene -ene H2C=CH2 ethene (ethylene) CC alkyne -yne HC≡CH ethyne (acetylene) R-X haloalkane halo- CH3Cl chloromethane -ol R-OH alcohol CH OH methanol (hydroxy-) 3 -amine ethylamine R-NH amine CH CH NH 2 (amino-) 3 2 2 aminoethane ether R-O-R ether CH OCH dimethyl ether (alkoxy-) 3 3 O O ethanal C aldehyde -al CH3CH (acetaldeyde) RH O O propanone C ketone -one RR CH3CCH3 (acetone) O O ethanoic acid R C carboxylic acid -oic acid OH CH3COH (acetic acid) O O methyl ethanoate RC ester -oate OR CH3COCH3 (methyl acetate) O O ethanamide RC amide -amide NH CH3CNH2 (acetamide) 2 R = alkyl group, an unfunctionalized saturated chain; X = halogen Organic Common Names H H O O ethylene CC formaldehyde acetaldehyde HCH CH3CH H H O O acetylene HCCH formic acid acetic acid HCOH CH COH 3 O OH benzene phenol acetone CH CCH 3 3 O toluene aniline NH2 benzaldehyde CH O xylene styrene benzoic acid COH .