Table Ill.
(310,- taken, mmoles X lo3 5 0 IHC10,i
Determination of Perchlorate in Samples"
Other inn taken, mmoles X 103
ClOr- found
mmoles Diff. mmoles Absorbance X lo3 x 103 hTone 0 452 5 0 0 0 5 0 tHC10;) 500 (HTSO,) 0 450 5 0 0 0 0 453 5 0 0 0 5 0 (HC10,) 100 (HCI) 2 85 -0 15 500 (H2SOr) 0 272 3 0 (HClO,) 2 9 -0 1 100 ( S a O H ) 0 276 3 0 IHCIO,) 6 9 -0 1 500 (HLSOI) 0 616 7 0 (HC10,) 0 625 7 0 0 0 7 0 (HClOr) 100 (TaOH) a Conditions. Sample volume 2 ml , 1 ml of ferroin, 3 ml of acetate buffer, and 4 ml. of n-butyronitrile added to sample
Extraction of 0.004 mmole of perchlorate in the presence of varying amounts of chlorate s h o w an increase in abqorbance once the chlorate concentration exceeds that of the perchlorate. Amounts of chlorate below 0.004 mmole have no effect. T'sing values from Figure 6, corrections in absorbance can be made for amounts of chlorate up to 0.1 mmole. .\bove this, the correction factor i. too large. Of courae, this requires a knowledge of the approximate amount of chlorate present. The effects of other foreign anions were studied in less detail. In Table I the qualitative effect of various anions is given. I n each case a n approximately
neutral solution containing ferrous-1 ,10-phenanthroline sulfate and the anion in question was equilibrated with n-butyronitrile. RESULTS
The analysis of sodium perchloratesodium chlorate mixtures is reported in Table 11. Corrections for the extraction of chlorate were obtained from Figure 6 and applied. Results for the determination of perchlorate in other samples of varying composition are given in Table 111. h sodium acetate-acetic acid buffer was used and the pH was adjusted to
5.0 before extraction. Good results were obtained for samples containing varying amounts of foreign anions and for samples that were originally acidic or basic. ;\n evaluation of all quantitative analyses prformed shovc-ed an average recovery of 99.0% u;ith a relati\-e standard deviation of d~2.07,. Ysing 0.004 mmole of perchlorate, the amount of complex extracted in one estraction is reproducible to 0.00005 mmole, from day to day. However. over a period of time with different lots of $ol\-ent, different pipets, etc.. it is advisable to repeat a standard plot. LITERATURE CITED
(1) illley, B. J., Dykes, H. W. H.. ASAI.. CHEM. 36, 1124 (1961). 12) Burns, E. A . , Sluraca. R. F.. Ibid.. 32, 1316 (1960). ( 3 ) Johannesson, J. K., Ibid., 34, 1111 11982) -\ -
(4) Xlargerum, D. TT., Banks, C. V,, Ibid.,26, 200 (1954). ( 5 ) Nebar, G. XI., Ramachandran, C. R., Ibzd., 31, 263 (1959).
RECEIVEDfor review June 4, 1963. Resubmitted SIay 4, 1964. Accepted July 29, 1961. Work performed in Ames Laboratoyy of U. S. Atomic Energy Commission.
infrared Spectra-Structure Correlations of Aliphatic Amides in the 700- to 250-Cm. Region -1
J. E. KATON, W. R. FEAIRHELLER, Jr., and J. V. PUSTINGER, Jr. Monsanto Research Corp., Doyfon 7, Ohio
b Spectra of 78 aliphatic amides of varying structure have been recorded and analyzed in the range of 700 to 250 cm.-' Most amides have three haracteristic absorptions in this region. The ronges at which these absorptions occur depend on the detailed structure in the vicinity of the amido grouping, but appear to be specific for a given structural class. Spectra-structure correlations and the nature of the vibrations giving rise to these absorptions are discussed.
T
1s A GREAT INTEREST in aliphatic amides because of their connection with the biologically important polypeptides and proteins. Therefore, the infrared spectra of this class in the 4000- to 700-cm.-' region have been well studied. Bellaniy (1) summarized published data on this class previous to about 1958 and disc u s e d spectra-structure correlations and asignments in this higher frequency HERE
2 126
ANALYTICAL CHEMISTRY
region. Little work has been carried out a t lower frequencies. Xiyazawa, Shimanouchi, and AIizushiina (10) studied several amides in the 700- to 400-crn.-l region, but many of these were not typical amides. More recently, several authors studied individual amides and assigned simple formamides (5,f 4 ) , acetamides ( 5 , 8 , 1 6 ) ,acrylaniide ( 4 ) , diketopiperazine ( 9 ) , and 2-pyrrolidone (2-pyrrolidinone) ( 2 2 ) . Much disagreement remains concerning assignment of the low frequency bands of these compounds, however. Previous publications from these laboratories ( 2 , 6, 13) have shown that other classes of carbonyl-containing compounds possess characteristic absorption frequencies below 700 em.-', whose positions depend on the detailed molecular structure in the vicinity of the carbonyl group. Amides behave in a similar fashion ( 7 ) . This paper reports the detailed results of an infrared spectral study of 78 aliphatic amides of varying structure in
the 700- to 250-cm.-1 region and shows that these compounds possess characteristic frequencies in this range similar to those previously reported for other carbonyl-containing compounds. EXPERIMENTAL
The majority of the samples used in this study are commercially available. Aifew were synthesized by conventional means. Samples of questionable purity were subjected to gas liquid chromatography, and if found impure were redistilled, recrystallized, or collected as chromatograph fractions to yield high purity material. The qpectra were recorded on a Perkin - Elmer 421 spectrometer equipped n i t h a midrange dual grating interchange for the 2000- to 2 5 0 - ~ n i . - ~ region. Ceqium iodide windows were used in the thermocouple and as cell materials. ; i special foam rubber-gasketed lucite dry box over the sample area permitted the instrument to be flushed with dry nitrogen while recording the
16 PRilMARY
2,o
18
25
30
40
L: Y
0
20
AMIDES
ALIPHATIC ( n > 3 ) a - B R A N C H E D ALIPHATIC
B - B R A N C H E D ALIPHATIC SECONDARY
AMIDES
ALIPHATIC N-METHYL ALIPHATIC (OTHER THAN N-METHYL)
6
-BRANCHED
2
N-CYCLOHEXYI
4
FORMAMIDES
3
u
TERTIARY
23
AMIDES
FORMAMIDES
4
OTHER
15
ANlLlDES
4
L A C TA MS DIAMIDES
600 Figure 1.
14
460
200
Spectra-structure correlation chart for amides in the 700- to 250-cm.-1 region
16
18
20
25
30
40 50
spectra. This dry box has a lucite air lock over the source compartment. Frequency error is considered to be k3 cin.-l maximum. Liquid samples were recorded in thicknesses from capillary film to 0.10 nim., and solid samples as mulls (Sujol and hexachlorobutadiene) and occasionally in solution. RESULTS
0 Figure 2 .
Partial infrared spectrum of lauramide
A spectra-structure correlation chart for amides in the 700- t o 250-cni.-1 region is presented in Figure 1 and the ranges of absorption are given in Table I. Talile I1 lists the major absorption bands and their estimated relative intensities for the 78 amide; studied. These intensities are relative in a given class and are for the 700- to 250c m - l region only. All hands are weak relative to bands in the higher frequency region. Figure 2 shows a relircsentative amide spectrum. VOL. 36, NO. 11, OCTOBER 1964
2127
Table I.
Range of Correlation Frequencies
Aliphatic (no a-branching or a-unsat uration) Aliphatic ( n > 3)
PRIMARY AMIDES 632-570 em.-' (s), 478-450 em.-' (m-s)
632-570 em.-' (s), 478-450 em.-l (m-s), 360-322 crn. (na-s) 66j-583 c 1 n - l (s), .520-495 em.-' (s), 320-305 e m - ' ( m - s ) . 585-570 c n (s), ~ 4~12-465 c111.-~ ( s j ,
a-Branched aliphatic p-Branched aliphatic
Aliphatic S-methyl .4liphatic straight chain (other than *Y-methyl) A\--Cyclohexyl
330-315
CIIi.-'
(m)
SECOXD.IRY il1r1oss 610-590 cIn. -I (m-s), 478-432 em. -l ( sj 610-590 (mi.-' (m-s), 478-432 cm.-' (s), 380-330 ~111. ( m-s) 575-352 cni.-' (s), 465-455 mi.-' (m-s), 380-330
CIII.
-' ( 7n-s j
672-628 em.-' ( m ) , 520-508 ern.-' (s), 350-330 cni.-' ( s ) T o definite correlation
a-Branched Formamides. AY-substituted
TERTIARY A4MIDES Other than formamides Formamides IXamides .Y-substituted anilides Lactams
598-572 (711.-l (s), 478-442 em.-' (m-s), 388-322 em.-' ( m ) 700-645 mi.-' (s), 390-342 cm.-' (m-a) 675-598 cni. -I (s), 595-540 cm.--I (m-s) 628-612 c m - ' ( m j , 570-532 (8). 450-440 cni.-I ( m ) ,408-308 (sin.- I ( s j 695-655 c m - ' (m-si, 497-470 cm-' ( s )
18
20
25
500
400
ACIDS STRAIGHT C H A I N ALIPHATIC a-BRANCHED
ALDEHYDES STRAIGHT C H A I N ALIPHATIC e - BRANCHED
KETONES STRAIGHT C H A I N ALIPHATIC 01-
BRANCHED
CVCLIC
AMIDES STRAIGHT C H A I N ALIPHATIC 0-IRANCRED LACTAMS
600
Figure 3. Spectra-structure correlation chart of the CC=O deformation vibration for acids, aldehydes, ketones, and amides
2128 *
ANALYTICAL CHEMISTRY
Figure 1 shows that the ranges of characteristic absorption maxima are generally quite narrow within a given structural class. This indicates that these correlations could be quite useful for diagnostic purposes. With the exception of forniamides, diamides, and anilides, which will be separately discussed, the amides shox three general areas of absorption. These are 695 to 550, 520 to 430. and 390 to 304 cm.? These general areas may then be broken down into much narrower ranges which depend on the more detailed structural characteristics of the coniiiounds. 695- to 55O-Crn.-' Region. ,111 amides have a t least one band in this region. T h e range for a specific structure, however, is never so great as the region, being only 75 em.-' at a niaxiniuni and usually much smaller. The primary amides tend to absorb over larger ranges than do any of the other structures. I n some cases more than one band i 5 observed in the region and the ahsorlition noted is often very tiroad. Figure 1 shows that the Scyclohexyl secondary amides absorb at the lower frequency end of the region and the lactanis at the higher frequency end. 520- to 430-Crn.-' Region. T h e straight chain amides absorb consistently in this region a t 480 t o 450 e m - ' On a-branching this band shifts to 520 to 495 c m - l , and 8-branching causes a smaller shift in the same direction. The latter shift is not of much diagnostic use because the range overlalis the straight-chain range, but the former is quite characteristic. This hand also shifts upward in the lactanis; h o w v e r , other correlation bands helow 700 ~111.-1 allow differentiation of lactams and amides. 390 to 305 Crn.-' Region. -is with thc other regions. the ranges noted here for specific qtructures are smaller t h a n the complete region. T h e r e are some minor exceptions to this correlation. A c et a mi d e, 11r o pi o n a mi d e, S-methylarnides, and lactams do not conqiqtently possess absorption bands in this region. Formamides, Diamides, and Anilides. Formamide has only one band helon. 700 c m - l This occurs as a .strong. very h a d ahsorption over the range 700 to 500 c m - ' The secondary forniamides do not possess any clonsistent absorption below 700 c i n - l , but the tertiarv formamides do ilossess a strong, l m a d band extending upward from ahout 650 c m - ' to above 700 and a second medium to strong hand at 390 to 340 c m - l A third hand occurs at 405 to 420 cm-'. hut the intensity varies greatly. The diamide; lmssess two consistent bands at 675 to 598 e m - l and at 595 to 540 e m - ' The anilides have four possible cor-
relation bands: 628 to 612, 570 to 532, 450 to 440, and 408 to 398 cm.-' The first, third, and fourth bands are near the charact,eristic ranges for other amides, but Jakobsen ( 3 ) has shown that monosubstituted benzenes absorb a t 625 , t o 606 and 560 to 420 em.-' This would indicate that' only the bands a t 570 to 532 and 408 to 398 em.-' are truly characteristic of anilides. DISCUSSION
Three major regions of absorption are noted in the aliphatic abmides. Although the specific position o f absorption depends on the detailed structure under consideration, absorption is noted near 600 and 500 cm.-l in all compounds, and near 350 cm.-I in nearly all compounds. Previous investigators who have assigned simple molecules are mostly in agreement that the band near 600 em.-' is caused by the S-C=O deformation and this assignment seems well founded. However, the assignment of the band near 500 cm.-' has variously been ascribed to a CO out-of-plane bending motion (9, fa),a CO deformation (fl), a CC deformation if 5 ), a CCO deforniaand a NCO deformation ( 4 ) . tion (j), The band near 350 cm.-' does not occur in the acetamides and has therefore not, been previously considered. The present results show that the band near 500 c m - l is almost certainly the C-C=O deformation. I t occurs in the same region as the C-C=O deformation in ketones (6), aldehydes (f3), and acids ( 2 ) . Furthermore, it hehaves in the same manner in t h a t a-branching shifts ii: to higher frequencies. Finally, there is no band in this region in formamides, a class of compounds which ca:nnot possess this vibration. The C-C=O deformation possesses the characteristics of a good group frequency. I n the classes ketones, aldehydes, acids, and amides it occurs in the region 430 to 565 em.-' This range of 135 em.-' may be favorably compared with the range of 110 cm.-l that is generally accepted for the carbonyl stretching frequency for these classes ( I ) . The C-C=O deformation vibration has the further characteristic that its range may be subdivided into much smaller ranges for specific structures. The carbonyl stretching vibration possesses this same characteristic, but it does not reflect a-branching as does the C-C=O deformation. Figure 3 is a brief correlation chart which shows the variation in the CC=O deformation vibration with structure. The figure represents the d a t a for 123 aliphatic carbonyl-containing comI)ounds, all of which possess this characteristic band. KO exceptions have been noted. Although no correlation for diamides in this region is given in Figure 1, all of the diamides possess a
Table II. Major Absorption Frequencies of Amides (Crn.-l) 700-615 (m, o b ) , 568 (s), 460 ( 5 ) Acetamide ( S ) 700-620 (s, vb, max. a t 690), 565 (s, ob), 475 (s, b ) Propionamide ( S ) 675-630 (5, v b ) , 575 ( m ) ,463 (s), 345 ( m ) Butyraniide ( 8 ) 585 (s, ob), 502 (s), 456 (s), 352 (s), 310 ( m ) Valeramide ( S ) 635 (s, v b ) , 515 (s), 488 ( m ) ,458 (s), 416 (s), 325 (s) Hexanamide ( S ) 635 (us, b ) , 525 (s), 472 ( m ) ,421 ( m ) ,355 ( m ) Nonamide ( S ) 641 ( u s , b ) , 530 (s), 495 ( m ) ,464 (s), 420 ( m ) ,360 ( m ) Lauramide (S) 621 (w), 508 (s), 491 (s), 309 (s), 280 ( m ) Acrylamide ( 8 ) 3-Methylbutyramide ( S ) 625 ( m ) ,572 (w), 510 (s), 343 (s), 306 (s) (isobutyramide) 675 (m, v b ) , 583 (s, b ) , 505 ( m ) , 464 (s), 425 ( m ) , 4-Methylvaleramide ( 8 ) 368 ( m ) ,330 ( m ) 2-Ethylbutyramide ( S ) 635 (s, v b ) , 500 (s), 435 ( m ) ,344 ( m ) ,306 ( m ) 2-Methylbutyramide ( S ) 620 (s, ob), 508 ( m ) ,495 (s), 425 ( m ) ,335 ( m ) ,308 ( m ) 615 (s, ob), 572 (s), 513 (s), 365 (s), 307 ( m ) Trimethylacetamide ( S ) 670 (s, v b ) , 620 (s, v b ) , 572 (s), 495 (s), 407 ( m ) ,379 3,3-l)imethylbutyramide ( 8 ) (81,315 ( m ) Cyclohexylcarboxamide ( S ) 665 (s, b ) , 524 (s), 502 (s), 380 ( m ) ,319 ( m ) ,295 ( m ) 2-Methylacrylamide ( S ) 620 (s, ub), 580 (s), 520 (s, b ) , 405 (m, b ) , 350 (w,b ) , 313 (s, b ) N-methylacetamide (1) 632 ( m ) ,598 (s), 438 (s) 2V-ethylace t amide ( I ) 620 (s, sh), 600 (s, b ) , 465 (s), 384 (s) 603 (s, b ) , 503 ( m ) , 486 ( m ) , 436 ( m ) , 335 ( m , b ) , iY-n-butylacetamide (1) 307 ( m , b ) N-t-butylacetamide ( I ) 622 (s, s h ) , 610 (s), 477 (s), 425 ( m ) ,338 (s, b ) N-cyclohexylacetamide ( 8 ) 637 ( m ) ,607 (s), 552 (s), 479 ( m ) ,450 ( m ) ,371 ( m ) , 302 ( m ) X-methylpropionamide (1) 694 (s, ob), 593 (s, sh), 579 (s), 440 (s), 315 (s, ob) X-t-butylpropionamide ( S ) 665 (s, b ) , 590 (s, b ) , 490 (s), 467 ( m ) ,333 ( m , v b ) N-cyclohexylpropionaniide ( S ) 570 (s, v b ) , 455 (s), 373 ( m ) ,353 ( m ) ,308 ( m ) S-cyclohexylbutyramide ( 8 ) 625 (s),605 (w, s h ) , 564 (s), 483 ( m ) ,453 ( m ) ,383 ( m ) , 350 ( m ) N-t-butylhexanamide ( 2 ) 675 ( 8 , ub), 595 ( s ) , 488 ( m , sh), 473 (s), 424 ( m ) , 332 (s) N-methyloctanamide (S) 692 ( m ) , 597 (s, b ) , 497 ( m ) , 432 (s), 393 (w) N-cyclohexyl-3-methylbutyr650 (w),588 (s), 456 (w),393 ( m ) ,347 ( m ) ,305 (s) amide ( S ) N-methyl-2-ethylhexananiide ( 8 ) 639 ( m ) ,516 (s), 445 ( m ) ,420 ( m ) ,332 (s) h'-t-butyl-3-methylbutyramide 670 (s, v b ) , 510 (s), 480 (s), 424 ( m ) ,400 ( m ) ,362 ( m ) , ( S ) (S-1-butylisobutyramide) 332 (s), 306 (s) N,X-dimethylacetamide (1) 592 (s), 474 (s), 420 ( m , b ) , 335 ( m , b ) N,S-diethylacetamide ( I ) 664 ( m ) , 613 (s), 595 (s), 502 ( m ) , 450 (s), 330 (m, u b ) iV,l'V-dipropylacetamide ( I ) 637 ( m ) , 598 ( s , sh), 590 (s), 525 ( m ) , 471 ( m ) , 433 ( m ) ,340 ( m ) N,N-diisopropylacetamide ( 1 ) 613 (s), 600 (s), 566 (w),515 (s), 500 ( m ) ,483 ( m ) , 444 ( m ) ,359 ( m ) N-cyclohexyl-N-ethylacetamide 635 (s), 610 (s), 588 (s), 570 ( m ) , 550 (w),517 (s), 505 ( m ) ,463 (s), 423 (s), 385 ( m ) ,350 ( m ) (1) N,N-dimethylpropionamide ( I ) 592 ( m ) , 576 (s), 490 (s), 448 ( m ) ,400 ( m ) ,348 (s) N,N-diethylpropionamide ( I ) 680 (w), 578 (s), 515 ( m ,sh), 503 ( m ) ,495 (s), 347 (s) N,N-di-n-propylpropionamide ( 1 ) 600 ( m ) ,580 (s), 523 ( m ) ,446 ( m ,sh), 435 (s), 413 ( m ) , 350 ( m , b ) N,N-diisopropylpropionamide ( 1) 650 (w),600 (s), 52,i (s), 497 ( m ) ,482 (s), 450 (w), 432 ( m ) , 368 (s), 310 (s), 298 ( m ) A',N-di-n-butylpropionamide (1) 620 ( m , sh), 583 (SI, 520 ( m , v b ) , 452 ( s ) , -380 ( m , v b ) , 345 ( m , b ) N,N-di-3-methylbu tylpropion638 ( m ) , 588 (m, b ) , 538 ( m ) , 463 (s), 438 ( m , s h ) , amide (1) -380 ( m , b ) , 365 ( m , b ) , -320 ( m , v b ) N,N-dimethylbutyramide (1) 700 ( m ) ,615 ( m ) ,602 (s),576 (s),475 (s, v b ) , 411 ( m ) , 385 (s), -330 (TU, u b )
(Continued)
VOL. 36, NO. 1 1 , OCTOBER 1964
2129
~~
Table II.
~
Major Absorption Frequencies of Amides (Cm.-l)
(continued)
N,N-diethylbutyraniide ( 1 )
595 (s, b ) , 502 ( s ) , 447 (s), 407 ( m ) , 376 (vi),325
N,1Z’-dimethyloctananiide ( I )
615 ( s , sh), 606 (s), 577 (s), 470 ( s ) , 430 (w),387 ( m )
(m,z b ) N,N-diniethyl-2-heptanamide ( I )
695 (s), 578 (s), 555 (s), 448 ( m , b ) , 405 ( m , b ) , 350 ( 8 )
Formamide ( 1 ) N-methylformamide ( I )
General abs. 500-700, no definite hands 700 (m, ob), 620 ( m ) ,361 (s, ob), 310 ( m ) , 297 (w)
N-cyclohexylformaniide ( I )
667 ( m ) ,640 (w),538 ( m ) ,509 (w),476 (s), 412 ( s ) 388 (s), 341 (w)
N-ethylformaniide ( I ) N,~V-diethylformaniide( 1 )
610 (s), 471 (s), 308 ( ~ nb,)
N-methyl-n-butylformaniide ( I )
700 (s), 660 (s), 645 (s, s h ) , 536 ( m ) ,518 ( m ) ,485 ( m ) , 408 ( m ) ,362 (s, vb), 345 ( s h ) ,320 ( m , s h )
N,N-dimethylformamide ( I ) N,N-diphenylacetamide ( S ) N,N-diphenylformamide ( S )
645 ( s ) , 503 (s, b ) , 419 (w,b ) , 347 ( m ) ,318 ( m )
657 (s), 353 (s), 321 ( m ) 702 (s, sh), 697 (s), 648 (s), 633 ( m ) ,616 (w), 585 572 ( m ) , 500 ( m ) , 463 ( m ) ,405 ( m )
(8)’
697 ( s ) , 681 (s), 615 (tu), 578 (s), 528 ( m ) , 440 (s), 408 ( m ) ,391 ( m ) ,321 ( m ) ,287 ( m )
n-Butyranilide ( S )
694 (s), 640 ( m ) ,617 (w),546 (s), 509 (s), 444 (w)) 361 ( n i ) ,297 ( m )
N-n-butylacetanilide ( I )
635 ( m ) , 623 ( m ) , 600 (s), 570 (os), 511 ( m ) , 450 ( m , b ) , 403 ( s ) ,390 (wj b)
Methylurea ( S ) Acetanliide ( S ) N-methylforliianilide ( I )
660 ( m ) , 400-625
(ab-max. a t 529, 506), 309
695 (s), 607 (s), 535 (s), 510
(8,
(8)
s h ) , 506 (s), 347 ( m )
698 (s), 678 ( s ) , 669 ( m ) ,619 ( m ) ,537 (s), 441 ( m ) , 415 ( m , sh), 407 (s), 350 ( 8 )
N-ethylacetanilide ( 8 )
702 ( v a ) , 630 ( m ) ,620 ( m ) ,600 ( m ) ,561 ( a ) , 477 ( w ) ~ 450 ( m ) ,404 (s), 363 (w)
N-methylacetanilide ( S )
625 ( m ) ,622 ( m , s h ) , 592 ( m ) ,559 (s), 452 ( m ) ,446 ( m , s h ) , 403 (s), 372 (w)
Carbanilide ( 8 )
698 (a), 675 ( m , v b ) , 644 ( m ) ,524 ( m ) , 508 (s), 498 ( m ) ,377 ( m )
Oxamide ( 8 )
615 ( u s , u b ) , 468 ( s ) , 340
blalonamide ( 8 )
675 (8, o b ) , 600 ( s , b ) , 578 ( s ) , 545 ( m , b ) , 448 (s), 404 (s), 353 (w)
Succinamide ( S )
(8,
b)
678
(8,
u b ) , 598 ( s , b ) , 547
Adipamide ( 8 )
650
(8,
o b ) , 552 (s), 485 (s), 365
Maleamide ( 8 )
600 (s), 576 (s), 562 ( m , sh), 420 ( m , b ) , 312 ( m , b )
Fumaramide ( 8 )
-650
N,,Z”-diethyl adipamide ( S )
675
hcetoacetanilide (S)
690 i s ) , 635 (s), 615 ( m ) , ,563 ( m , s h ) , 534 ( m ) , 523 (s), 503 (s), 463 (w),413 (w),393 (mj, 355 ( m )
2-Pyrrolidinone ( S )
686 (s), 680 ( a ) , 627 ( m ) ,537 ( m ) ,490 ( m , s h ) , 473 ( s )
Oxindole ( 8 )
674 ( a ) , 597 ( m ) ,554 ( a ) , 490 ( a ) , 410 (s), 333 (s), 296 ( m ) ,280 ( m , s h )
N-methyl-2-pyrrolidinone ( I )
656 (s), 615 ( m ) ,559 ( m ) ,4 i 0 (s), 308
AT-cyclohexylacetoacetamide ( S )
637 (s), 566 (s), 537 ( a ) , 485 (w))469 (w),452 ( m ,ah), 448 ( m ) ,379 (w),369 ( m )
N ,A7’-diallylmaleaniide ( S )
657 (s), 593 (s), 555 (w),524 (s), 460 (s), 405 (s), 3i3 (m)
Caprolactam ( S )
695 ( m ) ,583
Valerolactam ( I )
660 (s), 555 (w),497 ( s ) , 455 (s), 425
(3,
(8)
(8)
o b ) , 603 ( s ) , 566 ( s )
( 8 , bj, 590 (s, b ) , 457 (s), 380 (w), 365 Cm), 305 ( m , b )
(8))
band in the 430- to 5 6 5 - c n r 1 region, but the position is not very con;.i>tent. Although the frequency of the C-C=O deforniation does de1)end on the presence or absence of a-branching, it does not, to a first al)l)roxiniation, depend on branching a t ~)osition-:bpyond the a-carbon, lengthening the a-branch, or further a-substitution. Conjugation of the carbonyl group with a double bond tends to raise the frequency of the C--C=O deformation. The number of conipounds htudied is small, however, and this concluqion must be considered only tentative. The vibration giving rihe to the band near 350 em.-’ in aniides is not known but it is probably an out-of-plane vibration involving the amide grouping. The two distinct bands occurring near 600 ern.-’ in diamides are anomalous and their came i,s not knon-n. In the simple compounds they might be attributed to the two S-C=O deformations: these being coupled together. I t is unlikely that these two vibrations could be significantly coupled in the higher members of the series, however-e.g., adipamide.
(8)
505 ( a ) , 490 (s), 398 ( m ) ,323 ( m ) (8)
C-Methylmalonamide ( 8 ) 675 (3, v b ) , 570 ( a ) , 470 ( m ) ,425 ( m ) ,305 (w) S = solid; l = liquid; s = strong; ah = shoulder: m = medium; b = broad; w weak; vb = very broad: us = very strong.
ACKNOWLEDGMENT
The authors thank E. R. Lippincott for several helpful discusaions. LITERATURE CITED
(1) Bellamy, L. J., “The Infrared Spectra of Complex Molecules,” 2nd ed., TViley, New Turk, 1958. ( 2 ) Bentley, F. F., Ryan, 11. T., Katon, J. E., Spectrochim. dcta 20, 685 (1964). (3) Jakobsen, R. J., Bentley, F. F., A p p l . Spectr. 18, 88 (1964). (4) Jonathan, I., J . J l o l . Spectroscopy 6, 205 (1961). (5) Jones, R. L., Ibid., 11, 411 (1963). (6) Katon, J. E., Bentley, F. F., Spectrochim. d c t a 19, 639 (1963).
(7) Katon, J. E., Bentley, F. F., Pustinger, J. V., Jr., Ryan, >I. T., Paper A347, YIIth European Congress on llolecular Spectroscopy, Budapest, 1963. (8) Kutzelnigg, JT., Necke, R., Spectroc h m . =Icta 18, 549 (1962). ( 9 ) >IiyazaFaj T., J . M o l . Spectroscopy 4, 155 (1960). (10) LIiyazawa,
T., Shinianouchi, T., Ilizushima, S., J . Chem. Phys. 24, 408
(1956). (11) Nizushima, S., Simanouti, T., Xaga-
kura, S., Kuratani, K., Tsuboi, ll., Baba, H., Fujioka, O., J . Am. Chem.
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RECEIVEDfor review June 10, 1964. .Iccepted July 22, 1964 Work was supported bv the Research and Technology Division, I’nited States Air Force, under contract AF 33(616)-8465. 21 30
ANALYTICAL CHEMISTRY
