CHEM 213 Lecture Notes - Lecture 5: Hydrogen Bond, Ketone, Double Bond
Document Summary
Double bond equivalents: ring unsaturation next week ideas. C=o stretch about same place quite easily distinguish ketone from aldehydes. Low enough so its separated from spy stretches. C=o around same place as aldekydes and ketones ~1710 two oxygens huge -o-h 3400-2400 almost covers all c-h stretches. Ester has no broad o-h feature not really carbonyl that does distinguishing. ~1690, which is below other c=o primary amides have two n-h peaks. Acids: fairly easy to spot from these two n-h stretches (symmetric/assymetric) amides can hydrogen bond, so they are a little bit broadened secondary amide replaced one hydrogen, thus, only one n-h stretch one peak n-h. May be minor contributor but it has c-o character. Thus c=o stretching frequency goes down a little bit. Doesn"t work for esters because there are two competing e ects. Pulling electrons entity away from the carbon strengthens the bond. Dont quite get to 1700 because esters start at 1735cm-1.