Organic Chemistry: Determining Carbon Oxidation States and Electronegativities, Study notes of Organic Chemistry

Download Organic Chemistry: Determining Carbon Oxidation States and Electronegativities and more Study notes Organic Chemistry in PDF only on Docsity! Chem 30A F’07 Organic Oxidation States Electronegativities (Pauling scale) H 2.20 C 2.25 I 2.66 Br 2.96 N 3.04 Cl 3.16 O 3.44 F 3.98 To determine the oxidation state of carbon in an organic molecule: • attached hydrogen atoms contribute -1 to the oxidation state of carbon • attached carbon atoms contribute 0 to the oxidation state of carbon • attached heteroatoms (N, O, halogens) contribute +1 to the oxidation state of carbon • multiple bonds to carbon (e.g., C=O) are counted twice (+2) or three times (+3), as appropriate. Examples (bold name at left indicates type of molecule) alkane (saturated hydrocarbon) alkene (unsaturated hydrocarbon) aldehyde ketone carboxylic acid Looking ahead: We’ll see that oxidation reactions often increase the O/C ratio, while reduction reactions often increase the H/C ratio. CH4 H3C CH3 Cl methane ethane 2-methylbutane (a branched alkane) 2-chloropropane (a haloalkane) -4 -3 -3 -2 -1 0 H2C CH2 ethene (ethylene) -2 O H H formaldehyde H3C H O acetaldehyde 0 +1 O dimethylketone +2 OH O acetic acid +3 (CH3COOH)