Aug. 5, 1964
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COMMUNICATIONS TO T H E
EnmoR
3167
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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.
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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. at 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 at 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).
