drive motor nil1 not be altered. It was convenient to install a 20-tooth gear above the drive motor gear and a 96tooth gear above the 96-tooth pen drive gear. This is accomplished b y first installing two 1/4-inch sleeve couplings on the shafts protruding above the pen drive and motor drive gears, then inserting approyimately 3 inches of inch shafting into each of these two sleeve couplings and finally mounting a 96-tooth spur gear on the pen drive shaft about 3 inches above the other gear and a t a similar position on the drive motor extension mounting a 20-tooth spur gear. It is necessary to work at this elevation in this instrument to obtain the necessary clearances. I n making this installation some slight adjustment of the gear support will be required. With this installation, the drive motor shaft will now turn 4.8 times faster
tlinn the pen drive shaft, giving a n ovcr-all compression of the spectra equal to 7.5. It was convenient to loosen the setscrew on the sleeve coupling of the auxiliary gear and thus remove i t whenever the instrument is to be operatcd normally. This conversion from one gearing to another can be effected in seconds. If both the 48- and the 32-tooth gears are simultaneously removed and the auxiliary gear installed, the wave length drive is inoperative and the abscissa on the recording paper becomes a time scale. With the scanning time dial set a t the number one position, i t takes about 15 minutes for the present carriage to traverse the 14 inches of the recorder paper. The other time scale will double and quintuple the time duration for traverse. The entire installation may be made for less than $20. The necessary ma-
terial was purchased from stock from the P I C Design Corp., 477 Atlantic Ave., East Rockaway, L. I., N. Y. It included the following items; one G41-96 spur gear; one G41-20 spur gear; two D1-3 sleeve couplings and two A3-35 shafting. I ITERATURE CITED
(1) Hiskey, C. F., Young, I. G., -4NAL. CHEM.23, 1196 (1951). (2) Jones, J. H., Clark, G. R., Harrow, L. S., J . Assoc. Ob%. Agr. Chemists 34,135-79 (1951). (3) Morton, A., Stubbs, M., Analyst 71, 348 (1946). (4)Schiaffino, S. S., L o p , H. W., Kline, 0. L., Harrow, L. S., Ibid., 39, 180 (1956). Received for review December 27, 1960. Accepted March 17, 1961. Presented in part Gordon Research Conference on Analytical Chemistry, New Hanipton, N. H., August 1959 and the Eastern Analytical Symposium, New York, N. Y., November 5, 1959.
Infrared Studies of Some New Polycyclic Hydrocarbons and Their Derivatives Containing the CycIopropyI Ring S. A. LIEBMAN and B. J. GUDZINOWICZ Special P rojecfs Department, Research and Engineering Division, Monsanto Chemical Co., Everetf, Mass.
b Data are presented to illustrate the usefulness of previously reported frequency assignments for the cyclopropyl ring structure in some new polycyclic hydrocarbons and their derivatives in the regions of C--H stretching (-3050 cm.-l) and ring deformation (-1 020 cm.-'). From these investigations, it is noted that deviations do occur if one attempts to use the 860-cm.-' as well as these other spectral regions for the identification of the cyclopropyl ring without considering the type of compound in question, the presence of interfering groups, and the resolving power of the instrument.
P
INVESTIGATORS have noted that the cyclopropyl ring structure in organic compounds can be identified by characteristic absorptions in specific infrared spectral regions. Bartleson, Burk, and Lankelma ( 2 ) cited two absorption bands in alkyl cyclopropanes near 1020 em.-' and 860 em.-' as indicative of the presence of the ring system. I n 1952, Wiberley and Bunce ( 1 9 ) ,using lithium fluoride optics to study the absorption of nine cyclopropyl derivatives, showed two characteristic cyclopropyl CH2 absorption frequencies a t 3100 cm.-l and 3012 cni.-l resulting from asymmetric and symmetric CH2 stretching vibrations, respectively. It was concluded that,
REVIOUS
when used with the 1 0 2 0 - ~ m . - ~and 860-cm.-l bands, the CH2 stretching region could provide additional evidence t o substantiate the presence of the cyclopropyl ring. Recently, Wiberley, Bunce, and Bauer (90) extended the range of the two CHz stretching vibrations to 2995 t o 3033 cm.-' and 3072 to 3099 em.-' in a comprehensive study of more than 60 monosubstituted cyclopropanes, some of which had functional groups in their structures. However, all three absorption regions near 3050, 1020, and 860 em.-' have been questioned by investigators as to their usefulness for identification purposes. Derfer, Pickett, and Boord (7) presented data for 14 variously substituted cyclopropane hydrocarbons, utilizing a band centered a t 1010 cm.-l as characteristic of the cyclopropyl ring. The 860-cm.-l region failed to be useful because of its inconsistency. From qualitative studies of 34 cyclopropyl derivatives, Slabey (18) evaluated these three spectral regions and concluded that the 1050- t o lOOO-cm.-l region was most suitable for determining the presence of the cyclopropyl ring. Furthermore, he noted that, when instrumentation with higher resolution is available, the C-H stretching region could offer additional confirmation of the ring's presence. I n 1957 Allen et al. ( I ) , studying heavily substituted
cyclopropyl derivatives with functional groups adjacent to the ring, stated that neither the C-H stretching nor the ring deformation region near 1020 cm.-l was adequate t o characterize the cyclopropyl ring clearly. In more complex polycyclics, Josien, Fuson, and Cary ( I O ) , Barton (S), and Cole (6) utilized either individual or multiple absorption bands at frequencies of 3024 to 3058, 1010, 860, and 800 cm.-' to establish the presence of modified cyclopropyl structures. For nortricyclene compounds, Kaplan, Kwart, and von Schleyer (11) cited the 860-cm.-' frequency to substantiate the presence of substituted cyclopropanes with special reference made to the investigations of Hart and Martin (9) and von Schleyer and O'Connor (16). I n a series of nine monosubstituted nortricyclenes, Hart and coworkers observed that bands mere consistently present a t 860 and 790 cni.-l The failure of the usefulness of the 1020-cm.-l region was reported in 1958 by Paasivirta (15). Nevertheless, he found characteristic 850 to 860-cm.-l and 3050 to 3090-cm.-' absorptions in 10 compounds having the skeletal nortricyclene structure. A literature survey has revealed few recorded spectra of spiranes containing the cyclopropyl ring. Cleveland, Murray, and Gallaway (5) presented the spiropentane spectrum showing strong VOL. 33, NO. 7, JUNE 1961
931
:il,solytions a t 871, 990, :tiicI 1049 tin.-', in addition to hands :it 2085 and 3050 cni.-1 Spiro[2.5]0ctanc (4) absorbed :it 1020 cni.-1 and rs1iil)itcd a series of intense peaks in the 950- to 8 3 0 - ~ n i . - ~ region. liecent'lj,, Moore and Ward (f4) reported :i C---Ii stretcxhing frequency a t 20S8 cni. for 7,i'-spirobi[bicyclo 14.1.O]heptanc. Froin the above studics, it is apparent t h a t discrepancies occur if one attempts to use the three suggcstcd spectral regions for the identification of the cyclopropyl ring without considering the type of compound in question, the presence of interfering groups, and the resolving power of the instrument. EXPERIMENTAL
The infrared spectra were obtained using a Perkin-Elmer hIodel 21 doublebeam spectrophotometer equipped with sodium chloride optics. A standard
polystyrene film was used for wave length calibrations, and the accuracy of the instrunient was *0.01 micron or j=4 c m - l in the C-H stretching region. Reproducibility was estimated a t +0.01 micron or j=4 em.-' The spectra reported in this work for all compounds in the 4000 to 2500 cm.-' and 1111to 909-c1ii.-~ ranges were obtained using the following instrumental conditions : Iiesolu tion Response Chart speed Gain Suppression Source Response time
liquid films ill deniounttiblr cells or in fixed path length cells of 0.0278 or 0.05-nim. thickness as noted on each spectrum. The spectrum for compound V, a solid, was obtaiiied in n potassium bromide pellet. A11 compounds listed in Table I had a minimum 957& purity as determined by gas chromatography, with the exception of compound XII, which contained 19y0 of 4-cyclopropylcyclohesene.
927 1 1 micron per minute 6.0 2 0.3 ampere 3 seconds, full scale
A polystyrene spectrum is included in Figure 1 to show the resolving power and performance of the spectrophotometer a t these selected operating conditions. K i t h the exception of compound V, all samples were examined either RS thin
RESULTS AND DISCUSSION
The following spectral data are presented to illustrate the value of the assignments in the C-H stretching (-3050 cni.-l) and the ring deforniation (-1020 cm.-I) regions for the cyclopropyl ring based on infrared studies of some new polycyclic hydrocarbons and their derivatives. I n the evaluation of the C-H region of these hydrocarbons, ne11 known interfering
WAVE LENGTH IN MICRONS
2.5 3.0 3.5 4.0 2.5 3.0 3.5 4.0 2.5 3.0 3.5-4.02.5 3.0 3.5 4.0 2.5 3.0 3.5 4.0 2.5 3.0 3.5 4.0 100 80
60
z 40 0 5 v)
f 20
m z 4
a
4000
2500 4000
2500 4000
2500 4000
2500 4000
2500 4000
WAVE NUMBERS IN CM.-' Figure 1.
Characteristic cyclopropyl C - H
stretching frequencies in the 4000- to 2500-cm.-' region
See Table
932
0
ANALYTICAL CHEMISTRY
I for identificotion of I-X
2500
groups, surh as aromatic or unsaturated C-H, were cithcr absent or present in nc.gligible amounts. T o investigat further the validity of previous assigninents in the 1020- and SGO-cm.-' regions, compounds XI and XI1 were included in Table I, but excluded from Figure 1 since both contained the or =CH group. =C-H Since polycyclics I through VI1 and X I 1 in Table I are new compounds (12, IS), their spectra are reproduced in Figures 1 and 2 in both the 4000 to 2500 and 1111 to 909-cm.-' re,'mions. Although the syntheses of compounds VI11 (21) and XI (17) have been reported, their spectra were not found in the literature. The spectra of compounds IX and X are shown only in Figure 1 since the other regions of interest have been previously presented ( 8 ) . Table I shows that the two cyclopropyl CH2 stretching frequencies in compounds I through VI fall in the 3077to 2985cm.-' range. Furthermore, only the dispirane, sample VII, exhibited a significant lowering of the cyclopropyl CH2 stretching frequencies. The symmetric cyclopropyl CHe stretching absorption was presumably masked by
100
9
Table 1.
Characteristic Absorptions of Cyclopropyl Ring
Compound
Frequency, Cm.-1 C-H Ring St,retchine deformation
Structure
I Cyclohexyldicyclopropyl methanol
3077, 3003
10'20
3058, 2985
If11.j
3067, 2985
1010
Q
3067, 2991
1020
3067, 2994
1010-20
&
3058, 3003
1006, 1040
3030
1020-30
3003
1000
3012
1025
3003
1015-20
I1 3-Cyclopropylnorcarane QH,
I11 6',6',-Dimethylspiro[cyclopropane-l,2,-norpinane]
&CHI
IV Tricyclo[7.1.0.04~~]decane (low melting isomer) V Tricyclo[7.l.0.O4~~]decane (high melting isomer)
0
4.06qnonane VI Tetracyclo [3.3.1.02-
m
VI1 Dispiro [5.1.5.0]tridecane VI11 Spiro[bicyclo(B.l.O)hexane-6,1'cy clopentane]
@El
I X 7,7-Dichloronorcarane
@e &
X 7,7-Dibromonorcarane X I Tricyclo[3.2.1.0z~4] oct-gene XI1 3-Vinylnorcarane
1010, 1029
CHzCHo 1015
WAVE LENGTH IN MICRONS
IO
II
9
IO
1000
909
IIII
IO00
II
9
IO
II
9
IO
II
9
909
11111
1000
909
IIII
II
IO
ao 60
5 40 v)
I?
5 20 z a a
+
I- 100
z w 80
a 60
40
20 1111
909 .I
1000
WAVE NUMBERS IN CM' Figure 2.
909
1000
Spectra of polycyclic hydrocarbons and derivatives containing the cyclopropyl group in the 1 1 1 1 - to 909-cm.-' region See Table I for identification of I-XI1
VOL. 33, NO. 7,JUNE 1961
0
933
the predominant cyclohexyl CH2 groups. Compound VI1 was also examined with lithium fluoride optics to obtain higher resolution and its spectrum showed a weak absorption band a t 2960 em.-' in addition to that a t 3030 em.-' The compounds VI11 through X, which contain only tertiary cyclopropyl ring hydrogens, showed a single absorption near 3005 em.-' This would be anticipated since two absorptions in the 3000-cm.-' region would not appear if the ring unit C H R or CR2were present rather than the CH2 ring group (20). We noted that the parent compound of compounds IX and X, i.e., norcarane, has the characteristic cyclopropyl CH2 stretching frequencies at 3077 and 3003 em.-' For obvious reasons, samples XI and XII, which show absorptions in this region because of unsaturation, will not be discussed. The data presented in Table I show that significant absorptions appear consistently in the 1040- to 1008-cm.-l range with the majority centered near 1020-cm.-1 A deviation noted in this series is in the spectrum of compound VIII, which contains the cyclopropyl ring in a substituted form as part of a spiro and bicyclic structure. Since similar compounds of this type are not available for comparison, the significance of this deviation is not known. As in other forms of substituted rings, Le., the nortricyclenes, compound VI11 also shows absorption near 850 cm.-l From spectra reported by von Doering (8),compounds IX and X, with heavy ring substitution, exhibit absorptions a t
frequencies lower than 860 em.-' Bands appear a t 840 and 830 em.-', respectively. Likewise, cornpound XI absorbs near 850 em.-' and compound XI1 shows medium absorption a t 835 em.-' Generally, for compounds in this series, the band near 860 em.-' proved to be less useful than bands in the 3050- and 1020-cm.-' regions for the identification of the cyclopropyl ring. From these studies, the usefulness of the assignments for the cyclopropyl ring system in the 3050-cm.-' C-H stretching and 1020-cm.-l ring deformation regions has been confirmed and is in accord with the works of Wiberley et al. (19, 20) and Slabey (18). Although these assignments in some instances have limited value as noted, the benefit derived from their use in certain structural studies involving polycyclic hydrocarbons and their derivatives is well established. ACKNOWLEDGMENT
The authors thank W. R.Smith, J. C. Alm, R.H. Campbell, J. I;.Driscoll, and A. Bekebrede for their contributions to and helpful discussions of this work LITERATURE CITED
(1) Allen, C. F. H., Davis, T. J., Humphlett, W. J., Stewart, D. W., J . Org. Chem. 22, 1291 (1957). (2) Bartleson, J. D., Burk, R. E., Lankelma, H. P., J . Am. Chem. SOC.68,
2513 (1946). (3) ~, Barton. D. H. R.. J . Chem. SOC. 1951, 1444. (4) Bridson-Jones, F. S., Buckley, G. D.,
Cross, L. H., Driver, A. Y . , Ibid., 1951, 2999. ( 5 ) Cleveland, F. F., Murray, &I. J., Gallaway, R. S., J . Chenz. P h y s . 15, 742 (1947). (6) Cole, 9. R. H., IbLd., 1954, 3807. (7)
