Nov., 1961
EFFECTSOF RADIATION ON SOME ORGANIC INCLCSIOK COMPOUNDS
2029
ZFFECTS OF HIGH EXERGY RADIATION O S SOME INCLUSION COMPOUNDS OF UREA, THIOUREA AND HYDROQUIKOSE BYWILLIAMSEAMAN’ Department of Chemistry, King’s College, University of Durham, Newcastle-upon-Tyne 1, England Received Mav 1.8, 1961
The following inclusion compounds were irradiated with cobalt-60 y-rays: urea with 1,4-dichlorobutane (I), l-chlorododecane (11), 1,bdibromopentane (111), 1-bromodecane (IV), n-octadecane (V), sebacic acid (VI), cetyl alcohol (VII) and stearic acid (VIII) ; thiourea with 2-bromo-n-octane (IX), dicyclohexylamine (X), cyclohexanol (XI), cyclohexene (XII) , cyclohexanone ( X I I I ) , 2,3-dimethylnaphthalene (XIV), 2-methylna hthalene (XV) and camphene (XVI) ; and hydroquinone with sulfur dioxide (XVII) and hydrogen sulfide (XVIII). drnparisons were made with the corresponding irradiated physical mixtures in cases where the guest compounds were solid. From infrared absorption spectral evidence, explanations are suggested, based on spatial and chemical factors, for the occurrence or absence of interactions between host and guest and between components of the physical mixtures.
Organic inclusion compounds are characterized by a definite spatial relationship between the host and guest molecule^.^^^ It would be expected that if such compounds were irradiated, the occurrence or absence of interactions between host and guest, the nature of such interactions if they occur, and the differences in these respects between an inclusion compound of two substances and a random physical mixture of the same substances might depend upon the contiguity or lack of contiguity of certain groups and atoms as well as upon their chemical characteristics. The aim of the work reported here was to survey several classes of inclusion compounds in order to see what the nature of such effects was. It was thought that such a study should make a contribution to the field of solid state irradiation reactions and serve as a guide for a more detailed study of individual inclusion compounds. The polymerization by irradiation of a number of substances bound as channel compounds with thiourea and urea has been r e p ~ r t e d . That ~ work was not concerned, however, with interaction betmeeii host and guest but only with stereospecific effects on the polymerization of the included monomers. X study also has been reported on the radiolysis of pentane adsorbed on synthetic zeolite^.^ I n this work the inclusion compounds listed in the Abstract were irradiated with cobalt-00 y-rays in a nitrogen atmosphere to dosages of from 8.5 to 76 megareps. Corresponding to the compounds containing solid guest constituents (V, T’I, VII, VIII, XIV, XI- and XTI), physical mixtures of the guest and host compounds also were made and irradiated. Some of the compounds and mixtures, before and after irradiation, were separated into their components by treatment with water and solvent extraction. Infrared absorption spectra were obtained in order to determine whether interactions had occurred between host and guest and between the components of the physical mixtures and, where possible, to interpret the nature of the interaction. (1) On leave from Research Laboratories, Organic Chemicals Division, ilrnerican Cyanamid Company, Bound Brook, New Jersey (present address). ( 2 ) W. Sohknk, Ann. 566, 204 (1049). (3) H. M. Powell and J. H. Rayner. Nature, 163, 566 (1949). (4) J. F. Brown, Jr.. and D. W. White, J . Am. Chem. Soc., sa, 5671 (1960); D. M. White, rbzd., 8Z, 5678 (1960). ( 5 ) J. W. Sutherland and .4. 0. Bllen. abzd., 83, 1040 (1961).
Results In Tables I, I1 and I11 are listed those infrared absorption bands of the irradiated and unirradiated samples and, where applicable, of the physiral mixtures, for which irradiation caused a change in intensity, or a change in frequency of no less than 5 cm. -l, or caused the appearance or disappearance of a band, except that the appearance or disappearance of weak shoulders was not listed. For XJ-11 (see text) and XVIII the absorption band changes are given for the solids recovered by evaporating an aqueous solution of the clathrates before and after irradiation, as well as for the irradiated and unirradiated clathrates. For T-, J-111 and I X absorption band changes also are given for the watersoluble and ether-soluble or carbon tetrachloridesoluble fractions obtained from the irradiated and unirradiated compounds and mixtures after heating with water. (The fact that for V, VIII, IX, XVII and XT’III infrared absorption differences ascribable to irradiation are present even after solution and separation by solvents precludes the possibility of explaining the results that follow as being due to polymorphic modifications brought ahout by irradiation.) The symbols s, m, and w in the tables refer. respectively, to strong absorption bands (peak height from baseline equal to 50 to 100% of the strongest band in the spectrum); medium (20 to 50%) ; and weak (less than 20%). The symbol sh refers to “shoulder.” Absorption band frequencies are in em.-’. Urea Channel Compounds.-The oxygenated compounds VI, VI1 and VI11 show few changes (Table I), possibly because the presence of oxygen in the guest molecules minimizes the tendeiicy for transfer of electrons from (oxygen-containing) urea. On the other hand, the corresponding physical miutures are much more reactive, which emphasizcs the significance of spatial factors. The data for the ether-soluble and water-soluble fractions of the water-treated irradiated and unirradiated mixtures and compounds V and VI11 indicate that some irradiation effects persist even after sepnratioit of the compound and mixture into their componeiits. : t i i d that these effects are not identical for the compouiid and the mixture. The compounds TI, I11 and IV (Table I) show varging degrees of change. It might be expected
WILLIAMSEAMAN
5’01. 65
TABLE I INFRARED ABSORPTION BANDSOF UREACOMPOUNDS A N D MIXTURES (Cw-1) 1,5-Dibromopentane compound (111) Before After irradiation irradiation (68 mrep.)
1,4-Dichlorobutane compound (I) (15.0 mrep.)a
3262 w 3225 w 2817 w 1675 w 1667 w 1626 w 1486 w, sh 1464 s 1453 w,sh 1290 w 1269 w 785 m
(See text) 1-Chlorododecane compound (11) Before After irradiation irradiation (18.4 Inrep.)
3400 s 3218 s 2981 w 1634 w, 1618 w, 1468 w, 1379 R,
3413 s 3226 s 2994 w 1629 w, sh 1613 w,sh 1460 w, sh 1379 TV
sh sh sh sh
n-Octadecane (,V) Ether-sol., after irradiation and -hydrolysis ofMixture Compound
r 7 -
Before irradiation
hlixtureb After irradiation (26.8 mrep.)
3414 s 3221 m 1070 w
3428 m 1661 w 1626 w 719 m
3401 s 3215 m 1058 w Compound
3390 s 3218 m 1471 w, sh Mixture--
Sebacic acid (VI)
3413 s 3333 m 3218 m 2928 s 1484 w 1462 s 1410 w 1321 w 1302 s 1253 w 1238 s 1186 m 1163 w, sh 115ti s 1011 w 1004 w 930 m 75:; w 721 w 656 w
1408 w, 1321 w, 1300 m 1250 w, 1238 w 1186 w, 1163 s
Before irradiation
3419 s 3248 w, sh 3661 s 1464 s 1323 w 1161 s 1053 w IO00 w, sh 789 w,sh 784 s 715 m
Before irradiation
Compound-After irradiation (21.8 mrep.)a
3367 w 1466 w, sh 1453 w, sh 943 w
3401 s 3356 s 3211 m 2928 m 1709 w 1486 s
3367 w, sh 1471 w, sh 1460 w, sh 952 w
sh sh
3226 s 1250 w 1070 w
3221 s 1250 w, sh 1064 w
2930 w 1669 m 1613 m 1543 w, sh 1527 w, sh
2912 w 1678 m 1618 m 1538 w, sh 1520 w, sh
-
-Cetyl
alcohol (V11)Mixturee After irTadiation (15.3 m r e ~ . ) ~
c
Before irradiation
3410 s 3342 w, sh 3262 w, sh 3226 m 2915 s 1630 w 1488 m 1462 m
3425 s 3342 m 3262 w 3229 w, sh 2921 s 1613 w 1486 w 1460 s 1339 w 1157 s 1117 TT, sh 1087 w 1062 w 1044 w 1000 m
1163 m 1117 R 1099 w 1060 m 1039 w 955 w 729
sh sh
1013 m
UT
Compound
1681 w, sh
942 w
1681 R
721 w, sh
r r
3410 w 1656 w 1618 w 717 s
7
,
After irrndiation (21.8 mrep.P
1-Bromodecane compuund ( I Y ) Befpre After irradiation irradiation (7G nirep.)
Water-sol., after irradiation axid hydrolysis of Mixture Compound
3410 s 3226 m 1466 w, sh
r -
Before irradiation
3262 w, sh 3226 s 2790 w 1675 w, sh 1661 s 1616 w 1486 w 1464 w, sh 1453 s 1290 w, sh 1274 w 787 s
Mixturec 7 After irradiation 18.5 mrep.)a
3410 m 3255 w, sh 1661 w 1466 m 1330 w 1156 s 1064 w 1000 w 788 s 784 w, sh 718 w
Stearic acid (VIII) Ether-soluble after hydrolysis of -Mixture-Unirradiated Irradiated
1645 w 1464 w
Water-soluble after hydrolysis of 7 Mixtur-Unirradiated Irradiated
1645 w, sh 1464 m
3431 m 3339 m
2912 m 803 w 727 w
2845 w, sh 2795 w 1592 w, sh 1466 s 1156 s 1042 w
Compound
2916 s 725 w, sh
3448 m 3344 w 2912 w 2845 w 2804 w 1592 s 1458 s 1149 m 1047 w
Compound
3346 w
3333 w
2795 w
2793 m
EFFECTS OF RADIATION ON SOME ORGANIC INCLUSION COMPOUNDS
Nov., 1961
2031
Stearic acid (VIII)
r
Mixture c After irradiation (8.5 mrep.ja
Before irradiation
Water-soluble after hydrolysis of Mixture Unirradiated Irradiated
