7.76

SECTION 7

TABLE 7.31 Raman Frequencies of Triple Bonds

Abbreviations Used in the Table

m, moderately strong m–s, moderate to strong s, strong

s–vs, strong to very strong vs, very strong

Group		Band, cm 1				Remarks
R9C#CH		2160–	2100		(vs)	Monoalkyl substituted; C#C stretch
		650–	600	(m)		C#CH deformation
		356–	335	(s)		C#C9C bending of monoalkyls
R1 9C#C9R2		2300–	2190		(vs)	C#C stretching of disubstituted alkyls; sometimes two bands
9C#C9C#C9		2264–	2251		(vs)
9C#N		2260–	2240		(vs)	Unsaturated nonaryl substituents lower the frequency and en-
						hance the intensity.
		2234–	2200		(vs)	Lowered ca 30 cm 1 with aryl and conjugated aliphatics
		840–	800	(s–vs)		CCCN symmetrical stretching
		385–	350	(m–s)
		200–	160	(vs)		Aliphatic nitriles
H9C#N		2094 (vs)
Azides
		2170–	2080		(s)	Asymmetric NNN stretching
9N9N#N
		1258–	1206		(s)	Symmetric NNN stretching; HN3 at 1300 cm 1
Diazonium salts
		2300–	2240		(s)
R9N #N
Isonitriles
		2146–	2134			Stretching of aliphatics
9N#C
		2124–	2109			Stretching of aromatics
Thiocyanates
9S9C#N		2260–	2240		(vs)	Stretching of C#N
		650–	600	(s)		Stretching of SC

		SPECTROSCOPY				7.77
TABLE 7.32 Raman Frequencies of Cumulated Double Bonds
	Abbreviations Used in the Table
	s, strong			vw, very weak
	vs, very strong			w, weak
Group	Band, cm 1				Remarks
Allenes
C"C"C	2000–	1960	(s)		Pseudo-asymmetric stretching
	1080–	1060	(vs)		Symmetric stretching
		356			C"C"C bending
Carbodiimides (cyanamides)
9N"C"N9	2140–	2125	(s)		Asymmetric stretching of aliphatics
	2150–	2100	(vs)		Asymmetric stretching of aromatics; two bands
	1460				Symmetrical stretching of aliphatics
	1150–	1140	(vs)		Symmetric stretching of aryls
Cumulenes (trienes)
C"C"C"C	2080–	2030	(vs)
		878
Isocyanates
9N"C"O	2300–	2250	(vw)		Asymmetric stretching
	1450–	1400	(s)		Symmetric stretching
Isothiocyanates
9N"C"S	2220–	2100			Two bands
	690–	650			Alkyl derivatives
Ketenes
C"C"O	2060–	2040	(vs)		Pseudo-asymmetric stretching
	1130 (s)				Pseudo-symmetric stretching
	1374 (s)				Alkyl derivatives
	1120 (s)				Aryl derivatives
Sulfinylamines
R9N "S"O	1306–	1214	(w)		Asymmetric stretching
	1155–	989 (s)			Symmetric stretching

7.78

SECTION 7

TABLE 7.33 Raman Frequencies of Carbonyl Bands

Abbreviations Used in the Table

m, moderately strong m–s, moderate to strong s, strong

s–vs, strong to very strong vs, very strong

w, weak

Group		Band, cm 1		Remarks
Acid anhydrides
9CO9O9CO 9
Saturated		1850–1780	(m)
		1771–1770	(m)
Conjugated, noncyclic		1775
		1720
Acid fluorides	9CO9F
Alkyl		1840–1835
Aryl		1812–1800
Acid chlorides	9CO9Cl
Alkyl		1810–1770	(s)
Aryl		1774
		1731
Acid bromides	9CO9Br
Alkyl		1812–1788
Aryl		1775–1754
Acid iodides	9CO9I
Alkyl		ca 1806
Aryl		ca 1752
Lactones		1850–1730	(s)
Esters
Saturated		1741–1725		Alkyl branching on carbon adjacent to C"O
				lowers frequency by 5–15 cm 1.
Aryl and , -unsaturated		1727–1714
Diesters
Oxalates		1763–1761
Phthalates		1738–1728
C#C9CO9O 9		1716–1708
Carbamates		1694–1688
Aldehydes		1740–1720	(s–vs)
Ketones
Saturated		1725–1700	(vs)
Aryl		1700–1650	(m)
Alicyclic
n 4		1782	(m)
n 5		1744	(m)
n 6		1725–1699	(m)

	SPECTROSCOPY		7.79
TABLE 7.33 Raman Frequencies of Carbonyl Bands (Continued)
Group	Band, cm 1		Remarks
Carboxylic acids
Mono-	1686–1625 (s)		These -substituents increase the frequency:
			F, Cl, Br, OH.
Poly-	1782–1645		Solid state; often two bands
	1750–1710		In solution; very broad band
Amino acids	1743–1729
Carboxylate ions	1690–1550 (w)
	1440–1340 (vs)
Amino acid anion	1743–1729		Often masked by water deformation band near
	1600–1570 (w)		1630 cm 1
Amides (see also Table 7.30)
Primary
Associated	1686–1576 (m–s)
	1650–1620 (m)
Nonbonded	1715–1675 (m)
	1620–1585 (m)
Secondary
Associated	1680–1630 (w)		Both cis and trans forms
	1570–1510 (w)		Trans form
	1490–1440		Cis form
Nonbonded	1700–1650		Both cis and trans forms
	1550–1500		Trans form (no cis band)
Tertiary	1670–1630 (m)
Lactams	1750–1700 (m)

TABLE 7.34 Raman Frequencies of Other Double Bonds
		Abbreviations Used in the Table
	m, moderately strong		vs, very strong
	m–s, moderate to strong		w, weak
	s, strong		s–vs, strong to very strong
	w–m, weak to moderately strong
Group		Band, cm 1			Remarks
		Alkenes C "C
C "C		1680–1576 (m–s)			General range

HR1

	C "C	1648–	1638 (vs)		C"C stretching
	H	H
	H	R1		(vs)	C"C stretching
	C "C	ca 1650
		270–	252	(w)	C"C9C skeletal deformation

HR2

7.80			SECTION 7
TABLE 7.34 Raman Frequencies of Other Double Bonds (Continued)
	Group		Band, cm 1			Remarks
		Alkenes	C "C		(continued)
R1	R2	ca 1660		(vs)		C"C stretching
C "C
		970–952		(w)		Asymmetric CC stretching

HH

R1	H
C "C	1676–1665 (s)	C9C stretching

HR2

R1

R3

1678–

1664

(vs)

C"C stretching

C "C

522–

488 (w)

C"C9C skeletal deformation

R2

H

R1

R3

1680–

1665

(s)

C"C stretching

C "C

690–

678 (m–s)

Symmetrical CC stretching

510–

485 (m)

Skeletal deformation

R2

R4

424–

388 (w)

Skeletal deformation

Haloalkene

X fluorine

X chlorine

X bromine

X-iodine

C "C stretch of haloalkanes

H2C"CHX

1654

1603–1601

1596–1593

1581

HXC"CHX

cis

1712

1590–1587

1587–1583

1543

trans

1694

1578–1576

1582–1581

1537

H2C"CX2

1728

1616–1611

1593

X2C"CHX

1792

1589–1582

1552

X2C"CX2

1872

1577–1571

1547

1465 (solid)

Group

Band, cm 1

Remarks

C "N 9 bonds

Aldimines (azomethines)

H

1673–

1639

Dialkyl substituents at higher

C "N 9R2

1405–

1400

(s)

frequency; diaryl substituents

R1

at lower end of range

Aldoximines and Ketoximes

C "N 9OH

1680–

1617

(vs)

1335–

1330

(w)

Azines

C "N 9N "C

1625–

1608

(s)

SPECTROSCOPY

7.81

TABLE 7.34 Raman Frequencies of Other Double Bonds (Continued)

Group	Band, cm 1	Remarks

C "N 9 bonds (continued)

	Hydrazones
	H		H
	C "N 9N			1660–	1610		(s–vs)
	R1		R2
	Imido ethers
	O			1658–	1648			NH stretching at 3360–3327
	C "NH
								cm 1
	Semicarbazones and thio-
	semicarbazones
	H			1665–	1642		(vs)	Aliphatic. Thiosemicarbazones
	C "N 9N		NH2					fall in lower end of range.
				1620–	1610		(vs)	Aromatic derivatives
	C
	O (or S)
				Azo compounds 9N"N 9
	9N"N 9			1580–	1570		(vs)	Nonconjugated
				1442–	1380		(vs)	Conjugated to aromatic ring
				1060–	1030		(vs)	CN stretching in aryl com-
								pounds
				Nitro compounds N"O
	Alkyl nitrites			1660–	1620		(s)	N"O stretching
	Alkyl nitrates			1635–	1622		(w–m)	Asymmetric NO2 stretching
				1285–	1260		(vs)	Symmetric NO2 stretching
				610–	562	(m)		NO2 deformation
	Nitroalkanes
	Primary			1560–	1548		(m–s)
				1395–	1370		(s)	Sensitive to substituents attached
				915–	898	(m–s)		to CNO2 group
				894–	873	(m–s)
				618–	609	(w)
				640–	615	(w)		Shoulder
				494–	472	(w–m)		Broad; useful to distinguish
								from secondary nitroalkanes
	Secondary			1553–	1547		(m)
				1375–	1360		(s)
				908–	868	(m)
				863–	847	(s)
				625–	613	(m)
				560–	516	(s)		Sharp band