Aug. 5, 1964
-
COMMUNICATIONS TO T H E
EnmoR
3167
-
The observed values for several perfluoroalkylmethylenes are D 0.72 and E 0.021 cm.-l indicating an angle of 150-160° a t the divalent carbon atom." Comparison should be made with the corresponding linear structure which would have D 0.75 cm.-1,12in fair agreement with Zadependence. An interaction between the unpaired electrons, similar in magnitude to those observed in the alkyl nitrenes, was determined for methylsulfonylnitrene which has D = 1.581 cm.-', E = 0.0036 cm.-'. In contrast, the values for phenylnitrene (D = 0.99 cm.-l, E < 0.002 cm.-') indicate significant delocalization of one unpaired electron into the aromatic system. Acknowledgments.-We are grateful to Mr. R. M. R. Cramer and Mrs. B. I. Feuer for their assistance.
-
Figure 1
PZ1, a = 9.56 A., b = 17.2 A., c = 8.01 A., and B = 67.5O, with the polymer chains parallel to b' Weissenberg photographs of partially converted monomer E. WASSERMAN crystals showed that the following crystallographic G. SMOLINSKY planes of monomer and polymer are parallel to each W. A. YAGER 0th- : 1IZ,. II 20%.1; l12mon I I 202,1; 004mm I I
(11) Prom work with L. Barnrh, to be published. (12) 1. Higuchi I. C k m . Phyr., 8%. 1338 (1883). W e employ the calculated change io D 6 t h change in angle to correct the observed value
BELLTELEPHONE LABORATORIES MURRAY HILL, KEW JERSEY RECEIVED JUNE 4. 1964
oo2,01.
Preparation of Biaxially Oriented Polycapramide by the Solid State Polycondensation of a Single Crystal of e-Aminocaproic Acid' Sir : The possibility of preparing oriented polymer chains by polymerization in single monomer crystals was first demonstrated by the conversion of trioxane to p l y oxymethylene.2 Later it was shown that the polymer chains are oriented not only in the direction of the fiber axis but also in the plane perpendicular to The relationship of the orientation of the polymer crystallites to the crystallographic directions of the parent monomer has been fully clarified.' More recently, it has been shown that the heating of a single crystal of phthalanilic acid a t temperatures 50" below its melting point leads to highly oriented crystallites of N-phenylphthalimide.' This example of topotaxy is remarkable in view of the fact that the water split off in the reaction has to diffuse out of the crystal. U'e have now shown that an analogous phenomenon is possible in a polycondensation. Single crystals of caminocaproic acid (m.p. 204-205") heated in vacuo for 16 hr. a t 173' yielded highly oriented polycapramide as indicated by the X-ray diffraction photograph (rotation around b-axis of monomer) on Fig. 1. Weissenherg photographs proved that biaxial orientation was involved. The monomer crystal belongs to space group P2,/c, a = 8.56 A,, b = 5.90 A., c = 15.13 A,, and 0 = 103.13°,8 while the polymer has space group (11 Abstracted from the Ph.D. thesis to be submitted by N. Morosoff ofthe Polytechnic lnrtifute of Brooklyn in June,196s. This work was supported by grants fmm the National Seience Foundation and the U.S. Atomic Energy Commirrion. (21 H. W. Kohlrhuetfer and L. Spreoger, 2. P h w C h m . , Blb. 284 (1932); S. Okamura. K. Hayashi, and V. Kitsnishi, J. P d y m n S r i . , 58, 825 10 t h e Graduate School
(19621. (3) J. Lando. N . MorosoR, H. Morawetz, aod B. Post. ibid., (0. S24 (1962); S. Okamura. K. Hayashi. sod M . Nirhii, i b i d . , 80, S26 (1862). (4) G. Carazrolo. S. Leghirsi. and M. Mammi, Mobomnol. Chcm., eo, 171 (1863). ( 5 ) H. Morawetz. S. Z. lakabhnzy, J. B. Lando, and B. Post. P m . No!,. A m d . Sri. U .S.,49, 788 (1963). The paper refers to the reaction product e r m n M u S l Y PI
h'-phen~lphtlialamide.
(6) F. Guntber, Kallaid-Z., 108. 182 (1844): P.DLWolfe, ASTM Povder Diffraction Pilc Card 7.882.
These data indicate that the polymer chains grow parallel to the intersection of the 004 plane with the 110 or 170 plane of the monomer. The polymerization involves a contraction of 17% in the direction of the chain axis and an 18% reduction of volume; i t is remarkable that this may be accomplished with retention of chain orientation. (7) D. R. Holmu, C. W. Buon. and D. I. Smith, 1. Pdymrr Sci.. 17. 169 (186s). (8) On leave from the Institute of Maeromoleeulsr ChcmiotrY, Czecbodwatian Academy of Science%, Prague, Czeebo~lovakia. (e) To whom mmmunieatioon should be addressed.
DEPARTMENT OF CHEMISTRY
POLYTECHNIC INSTITUTEOF BROOKLYN BROOKLYN 1, NEW YORK RECEIVEDJUNE 12. 1964
N. MOROSOFP D. LIM* H. MORAWETZS
The Photochemical Reduction of Rare Earth Ions in Fused Halides1 Sir: The reduction by X-rays2 and y-rayss~'of rare earth ions incorporated in crystalline halide hosts to lower oxidation states is well known. Recent studies a t these laboratoriess have shown that only the locally uncompensated rare earth ions are capable of being photoreduced, and, in addition, the divalent rare earths so produced are readily reoxidized by thermal and optical processes. The instability of the divalent state is due to interstitial halogen atoms which remain in the crystal after irradiation and which eventually recapture their electrons. Irradiations of molten halides containing rare earths, which would eliminate most of the inherent difficulties associated with the solid-state irradiations, were therefore carried out. In preliminary studies, molten solutions of dried and brominated BaBrz with 0.2 mole 70 (1) T h e raenrch reported in t h i s p a p s was sponsored by the Air Force Materiels Laboratory, Research and Tlcchnology Division. Air Force Spfemr Comrnaod, Wright-Patterson Air Force Barr. Ohio. under Contract No. AF33(067)-11221. (2) W . Hayes and J. W. Twidcll, 3. Chrm. Phyr., 36. IS11 (18611. @) J. R . OConoer and H. A. Bontick, J. A P P l . P h y s . , SS, 1868 119621 (a) 2. Kiss and R. Duocan. Pror. I . R . B . (Inrt. Radio Engrr I , SO, 1631 (1962). ( 5 ) P . K . Pong, 1.C h r m . Phyr., 11. 245 (1904).
3168
COMMUNICATIONS TO THE EDITOR
Tm3+ were irradiated with (1) y-rays, (2) the output of a low pressure mercury lamp, or (3) with a low pressure hydrogen discharge produced within the quartz reaction tube itself. The oxidized anionic species were swept out or trapped out of the reaction tube. Cpon cooling the molten bromides, each of the three radiation treatments showed significant quantities of divalent thulium. A typical spectrum of T m Z f in BaBrz taken a t 77'K. is shown in Fig. 1.
Vol. 86
Acknowledgment.-The help of Mr. R. Bailey in the y-ray work is gratefully acknowledged. RCA LABORATORIES PRINCETOS, XEWJERSEY 08540 RECEIVED J U N E5 , 1964
H . L PINCH
1,6-Oxido [ 101annulene and 1-Benzoxepinl
Sir :
We have found that base treatment of 2,3,6,7-tetrabromo-9,lO-oxidodecahydronaphthalene(11) gives rise to 1,6-oxido[10]annulene (IV), as well as to l-benzoxepin ( V I ) . 2 This synthesis of I V resembles the recently described synthesis of the related 1,G-methano[lO] annulene by Vogel and Roth. The tetrabromide I1 was prepared by addition of bromine to 9,10-oxido-1,4,5,8,9,10-hexahydronaphthalene (I)4in chloroforn solution, whereby one isomer (m.p. 160-1G2°) was isolated by crystallization in ca. 45% yield. Dehydrobromination of this substance with ethanolic potassium hydroxide a t 50-55', followed by chromatography on alumina, produced first the oxepin VI (ca. 205?&yield) and then the annulene I V (ca. 50% yield). l,&Oxido[10]annulene (IV), CloHsO, formed lightI yellow crystals, m.p. 53-54', infrared band (KBr) a t I I I Ik-Y-rI I I I \ ! P l J I 6.51 p. The ultraviolet spect.rum [XFSH255 mp, 299, 1.06 1.09 1.12 1.15 1.18 1.21 and complex band a t ca. 392 ( e 72,000, 6900, and 240)] WAVELENGTH IN MICRONS resembled that of the corresponding 1,6-methanoFig. 1.-Fluorescence of y-ray reduced (in t h e fused state) Tm2' c ~ m p o u n dand , ~ pointed to the fully conjugated strucin BaBrz ( T = 77°K.). ture I V rather than to the alternative tricyclic formulation 111. The n.m.r. spectrums showed an AzBz In the case of the y-ray treatment, a dosage of less pattern in the 2.23-2.81 region (centered a t r 2 . 5 2 ) , than lo4 rads was used. Generally, dosages of up to similar to that of naphthalene ( T 2.05-2.71, centered lo7rads were found to be necessary for similar reduction a t 2.38). in the solid.5 The light from the quartz mercury vapor The annulene IV is a ten r-electron system, and therelamp was focused on the surface of the melt from outfore complies with Hiickel's rule. Moreover the carbon side the furnace and the reaction tube. Illumination skeleton is presumably not seriously distorted from a was carried out for about 1 hr. The low pressure hymean plane, and the substance should consequently be drogen discharge was obtained by placing a Tesla coil aromatic.6 That the compound in fact is aromatic is on the reaction tube with about 0.1 mm. pressure of shown by the n.m.r. band positions a t low field, demhydrogen flowing through the tube. The discharge was onstrating the existence of a ring current. The annumaintained for about 30 min. lene is best represented by the expression V , indicating The intensity of the T m 2 +fluorescence obtained from delocalization of the r-electron system. the low pressure hydrogen discharge material indicates 1,G-Oxido[ 10lannulene can be made to undergo eleca level of reduction much greater than that possible trophilic substitution reactions. For instance, nitrathrough reduction by solid-state irradiation. The extion with cupric nitrate and acetic anhydride for 5 tent of reduction in the solid-state irradiation is limited min. a t room temperature produced two isomeric by the site-selection mechanism mentioned a b ~ v e . ~ ,mononitro ~ compounds, C K I H ~ N Oeach ~ , in ca. 30% In the molten state, the ionization of the anions by yield. The more strongly absorbed on alumina [ni.p. radiation and their subsequent removal from the 48-49'; 242 mp, 279, and 349 ( e 21,500, 26,500, solution should permit the reduction of all the rare and 7500)] proved to be the &nitro isomer VII, since earth ions present. The BaBrz-Tm2+ crystals were the lowest field bands in the n.m.r. spectrums consisted fused and regrown several times with little or no loss of a one-proton singlet (HI) a t 7 1.22 as well as a oneof the divalent state. This is indicative of the stability proton doublet (H3) a t r 1.40 ( J = 10 c.P.s.). The of the reduced rare earth ions produced by radiation in (1) P a r t X X X I I I in the series "Unsaturated Macrocyclic Compounds." the fused state to thermal reoxidation. No optical F o r part X X X I I , see 4.E. Beezer, C T. Mortimex. H . I ) . Springall, F. Sondheimer. and R Wolovsky, J . C h e m . S O L .in , press. reoxidation experiments were done, but in the absence ( 2 ) T h e isomeric 3-benzoxepin has been reported previously [ R . Dimroth of known electron traps, such processes are not expected and G. Pohl, A n p e w , Chem., 75, 436 (1981), for derivatives of 3-benzoxepin. to occur. see K . Dimroth and H. FI-eyschlag. Brv. 90, 1623 (1957)). ( 3 ) E . Yogel and H . D Roth. A n g ~ wC. h m . , 76, 145 (1964). Further work on other halide hosts containing various ( 4 ) This substance is readily available from naphthalene in high yield by rare earth ions and on the mechanism of the reduction a t w o ~ s t e psequence [ W . Hbckel and H Schlee, Be r... 88, 346 ( 1 9 5 5 ) : e . .4. process is in progress and will be described more fully Grob and P. W. Schiess. H d z f . Chim. Acta, 43, 1546 (1960) 1. ( 5 ) All n.m.r. spectra were determined in deuteriochloroform solution a t a later date.
I
(6) P . M. Heyman and Z Kiss, private communication.
a t 60 Mc. 'sec. (6) Sre F. Sondheimer. P U Y PA p p l . C h e w . . 7 . 383 fl963)
