SPECTROSCOPY

7.71

7.6RAMAN SPECTROSCOPY

TABLE 7.30 Raman Frequencies of Single Bonds to Hydrogen and Carbon

Abbreviations Used in the Table

m, moderately strong m–s, moderate to strong

m–vs, moderate to very strong s, strong

vs, very strong

vw, very weak w, weak

w–m, weak to moderately strong w–vs, weak to very strong

Group	Band, cm 1					Remarks
	Saturated C9H and C9C
9CH3	2969–	2967		(s)
	2884–	2883		(s)
	ca 1205		(s)			In aryl compounds
	1150–	1135				In unbranched alkyls
	1060–	1056				In unbranched alkyls
	975–	835	(s)			Terminal rocking of methyl group
	280–	220				CH2 9CH3 torsion
9CH2 9	2949–	2912		(s)
	2861–	2849		(s)
	1473–	1443		(m–vs)		Intensity proportional to number
	1305–	1295		(s)		of CH2 groups
	1140–	1070		(m)		Often two bands; see above
	888–	837	(w)
	425–	150
	500–	490				Substituent on aromatic ring
9CH(CH3)2	1350–	1330		(m)
	835–	750	(s)			If attached to C"C bond, 870–
						800 cm 1. If attached to aryl
						ring, 740 cm 1
9C(CH3)3	1265–	1240		(m)		Not seen in tert-butyl bromide
	1220–	1200		(m)		Not seen in tert-butyl bromide
	760–	685	(vs)			If attached to C"C or aromatic
						ring, 760–720 cm 1
Internal tertiary
carbon atom	855–	805	(w)
	455–	410
Internal quaternary
carbon atom	710–	680	(vs)
	490–	470

7.72

SECTION 7

TABLE 7.30 Raman Frequencies of Single Bonds to Hydrogen and Carbon (Continued)

Group		Band, cm 1				Remarks
		Saturated C9H and C9C (continued)
Two adjacent tertiary
carbon atoms		730–	920			Often a band at 530–524 cm 1
		770–	725			indicates presence of adjacent
						tertiary and quaternary carbon
						atoms.
Dialkyl substitution at
-carbon atom		800–	700	(m–s)
		680–	650	(vs)
		605–	550
Cyclopropane		3101–	3090
		3038–	3019
		1210–	1180 (s)			Shifts to 1200 cm 1 for mono-
						alkyl or 1,2-dialkyl substitution
						and to 1320 cm 1 for gem-1,1-
						dialkyl substitution
Cyclobutane		1001–	960	(vs)		Shifts to 933 cm 1 for monoalkyl,
						to 887 cm 1 for cis-1,3-dialkyl,
						and to 891 cm 1 plus 855 cm 1
						(doublet) for trans-1,3,-dialkyl
						substitution
Cyclopentane		900–	800	(s)
Cyclohexane		825–	815	(vs)		Boat configuration
		810–	795	(vs)		Chair configuration
Cycloheptane			ca 733
Cyclooctane			ca 703
CH3		1392–	1377
"C		450–	400	(vw)
		270–	250	(m)
CH3
CH3	H	1380–	1379
C "C		492–	455	(vw)
		220–	200	(m)
H	CH3
CH3	CH3	1372–	1368
C "C		970–	952	(m)
		592–	545	(vw)
H	H
		420–	400	(m)
		310–	290	(m)

SPECTROSCOPY

7.73

TABLE 7.30 Raman Frequencies of Single Bonds to Hydrogen and Carbon (Continued)

	Group		Band, cm 1				Remarks
			Saturated C9H and C9C (continued)
CH3		CH3	1385–	1375
C "C
			522–	488 (w)
CH3		H
CH3		CH3	1392–	1386
C "C			690–	678 (m–s)
			510–	485 (m)
CH3		CH3
			424–	388 (w)
C 9C 9C			1170–	1100	(w–m)
			600–	580 (m–s)
O
C 9C 9			1120–	1090	(m–vs)		Tertiary or quaternary carbon ad-
							jacent to carbonyl group low-
O
							ers the frequency 300 cm 1.
			600–	510 (w–m)
9CH2 9CO9			1420–	1410	(s)
9CHO			2850–	2810	(m)		Often appears as a shoulder
			2720–	2695	(vs)
			Unsaturated C9H
9C#C9H			3340–	3270	(w–m)		Alkyl substituents at higher fre-
							quencies; unsaturated or aryl
							substituents at lower frequen-
							cies
	H		3040–	2995	(m)
C "C
	H		3095–	3050	(m)		Asymmetric "CH2 stretch
C "C
			2990–	2983	(s)		Symmetric "CH2 stretch
	H
H		R	1419–	1415	(m)		Plus "CH and "CH stretching
C "C			1309–	1288	(m)		bands

HH

H	R	1	1413–	1399 (m)	Plus "CH2 stretching bands
			909–	885 (m)
	C "C
			711–	684 (w)
H	R2

7.74

SECTION 7

TABLE 7.30 Raman Frequencies of Single Bonds to Hydrogen and Carbon (Continued)

	Group	Band, cm 1		Remarks
		Unsaturated C9H (continued)
R1	R2
	C "C	1270–1251 (m)		Plus "CH stretching band

HH

R1	H
C "C	1314–1290 (m)	Plus "CH stretching band

HR2

R1	R3	1360–	1322		(w)	Plus "CH stretching band
C "C		830–	800	(vw)
R2	H
			Hydroxy O9H
Free 9OH		3650–	3250		(w)
Intermolecularly bonded		3400–	3300		(w)
Aromatic 9OH		ca 3160		(s)
9OH		1460–	1320		(w)	Common to all OH substituents
		1276–	1205		(w–m)	Primary
		1260 (w–m)				Secondary
C9C9OH primary		1070–	1050		(m–s)	CCO stretching
		1030–	960	(m–s)
		480–	430	(w–m)		CCO deformation
C9C9OH
Secondary		1135–	1120		(m–s)
		825–	815	(vs)
		500–	490	(w–m)
Tertiary		1210–	1200		(m–s)
		755–	730	(vs)
		360–	350	(w–m)
9CO9O9H		1305–	1270			CO stretching
		N9H and C9N bonds
Amine	N 9H
Associated		3400–	3250		(s)	Primary amines show two bands.
Nonbonded		3550–	3250		(s)
Salts		2986–	2974			Often obscured by intense CH
						stretching bands
9NH2		1650–	1590		(w–vs)	Bending

SPECTROSCOPY

7.75

TABLE 7.30 Raman Frequencies of Single Bonds to Hydrogen and Carbon (Continued)

Group	Band, cm 1				Remarks
	N9H and C9N Bonds (continued)
Amides
Primary	3540–	3500	(w)		Both bands lowered ca 150 cm 1
	3400–	3380	(w)		in solid state and H bonding
	1310–	1250	(s)		Interaction of NH bending and
					CN stretching; lowered 50 cm 1
					in nonbonded state
	1150–	1095	(m)		Rocking of NH2
Secondary	3491–	3404	(m–s)		Two bands; lowered in frequency
					on H bonding and in solid state
	1190–	1130	(m)
	931–	865 (m–s)
	430–	395 (w–m)
9CO9N	607–	555 (m)			O"CN bending
C 9N 9C	1070–	1045	(m)		Stretching
9
C
C 9N
Primary carbon	1090–	1060	(m)		CN stretching
Secondary carbon	1140–	1035	(m)		Two bands but often obscured.
					Strong band at 800 cm 1
Tertiary carbon	1240–	1020	(m)		Two bands. Strong band also at
					745 cm 1