CHM247H1 Lecture 1: CHM247 Lectures 1-5
Document Summary
Degrees of unsaturation e(cid:448)ery loss of (cid:1006) h"s = (cid:1005) dou. Cnh2n+2 cnh2n ring = 1 dou double bond = 1 dou triple bond = 2 dou (cid:2160)(cid:2171)(cid:2177)=[(cid:4666)(cid:2779)(cid:2159)+(cid:2779)(cid:4667) (cid:4666)(cid:2164)(cid:4667)+(cid:2163)(cid:2200)(cid:2197)(cid:2203)(cid:2198) (cid:2178) (cid:2163)(cid:2200)(cid:2197)(cid:2203)(cid:2198) (cid:2178)(cid:2165)(cid:2165)] (cid:2160)(cid:2171)(cid:2177)=[(cid:4666)(cid:2779)(cid:2159)+(cid:2779)(cid:4667) (cid:4666)(cid:2164)(cid:4667)+(cid:4666)(cid:2170)/(cid:2172)(cid:4667) (cid:4666)(cid:2162)/(cid:2159)(cid:2194)/(cid:2158)(cid:2200)/(cid:2165)(cid:4667)] (cid:2779) (cid:2779) *in a molecule, count rings & double/triple bonds. Ir radiation has lower frequency, longer wavelength than red light warmer object more ir emitted used in thermography for diagnosis of tumours (cid:2161) (cid:4666)(cid:2187)(cid:2196)(cid:2187)(cid:2200)(cid:2189) (cid:2197)(cid:2188) (cid:2198)(cid:2190)(cid:2197)(cid:2202)(cid:2197)(cid:2196)(cid:4667)=(cid:2190)(cid:2188)=(cid:2190)(cid:2185) (cid:2205)(cid:2183)(cid:2204)(cid:2187)(cid:2196)(cid:2203)(cid:2195)(cid:2184)(cid:2187)(cid:2200)=(cid:2778) Ir causes increased bond stretching vibrations (and bending, but stretching more important) Ir active: vibrational stretching that changes the dipole moment. * no change in dipole = no ir signal stronger bonds, higher frequency lighter atoms, higher frequency. Ir light absorbed if in resonance with bond vibration or exact multiple (2x, 3x, 4x) H-bonding little, a lot, varies more h-bonds, weaker o-h bond, (-) frequency, broad signal conjugated (-) s-character (-) k, (-) wavenumber than other c=c. Cl-ch=o, electro(-)ve atom moves e- from o to strengthen c=o.
