COMMUNICATIONS TO THE EDITOR
4116
ON THE STRUCTURE OF TETRABORANE
Sir: We have reinvestigated gaseous tetraborane by electron diffraction. The butane-like model with tetrahedral bond angles as reported by Bauerl is incompatible with our data; values of L B-B-B = 90" and LB-B-H = 133.5' do bring i t into agreement, but the latter angle is out of the question, especially for the "methylenic" hydrogen atoms. No exhaustive investigation of the butane-like structure was attempted, however, because a structure (Fig. 1) plausibly related to the known boron hydride structures' was discovered and shown
Vol. 75
established by Nordman and Lipscomb by the crystal structure investigation reported in the following Communication. The atomic arrangement is closely similar t o that of the apical groups in decaborane and is comparable to the arrangements in diborane and stable pentaborane. Approximate values for the numerous parameters of the Czv model are BI B2 = 18.5 A , B1 BZ = 1 7 6 b B? B i = 2 8 8 a (Dihedral LB1B3Ba-BIB3B,= 123'32') U i Ha = B2-11; = B2Hs = 1 19 A B1-H6 = 133 ii , BI-Hs = 1 13 H, in plane of BIB2B3 LE4-BI-€& = 118"20' arid LB1,~-B2-H7,s= 117"6'
A,
These values were obtained primarily from the radial distribution curve (Fig. 2 ) ; they were refined by a (necessarily incomplete) correlation treatment. The He parameters aFe highly uncertain, but the B-H distance 1.19 A. and the B-B bond distances warrant comparison with the crystal values. \?'e are indebted to Professor A. B. Burg and Mr. E. S. Kuljian for the samples of tetraborane and to the Office of Naval Research (Contract N6onr 24-1.123)for support during this investigation. l R I B U l I ~ \ \ U 18% A \ D C R E L L I V LABORATORIES M O R T O V E JO\IES OF CHEMISTRY, CALIFORVIA KEUVETHHEDBERC I\STITUTE OF TECHNOLOGY \-ERYER SCHOMAKER I'4541SE\A 1,C A L I F O R N I A cO\
Fig. 1.-The
(:ALE5
B4Hlostructure.
to be in excellent agreement with the diffraction pattern early in our and has since been
VISUAL
'TU 2,
1,
RADIAL
3,
4.
THEORETICAL
INTENSTY
DISTRIBUTION
A
6,
INTENSITY Cev
I
BUTANE-LIKE
eo,
40.
60,
80.
100,
q
Fig. 2.---Visual, radial distribution a n d theoretical intenThe theoretical intensity curves are for thc butane-like model with L R-B-B = 90" and L R-B-H = 133.5" and for the CzY model dewribed in the text. sity curves.
RECEIVED JUUE 30, 1953
THE MOLECULAR STRUCTURE OF B4Hlri
Sir: As a result of a complete analysis of 616 observed reflections from a single crystal of BdH10, we have determined the molecular structure. There are four molecules in a monoclinic unit cell having parameters a = 8.68, b = 10.14, c = 5.78A. and 0 = 105.9". The space group P21/n is unambiguous, and the twelve independent positional parameters of the boron atoms were determined from three-dimensional Fourier analysis. The hydrogen atoms were readily observable, and were also located more preciseIy from a threedimensional Fourier series from which the boron atoms had been subtracted. The molecular structure of B4H10 is shown in Fig. 1. No molecular symmetry elements are required by the space group of the crystal, but the molecular dimensions indicate that the symmetry of the isolated molecule is CZv. For brevity, we n n
Y
Y
_ I _ _ ~
(1) S. H. Bauer. THISJOUXNAL, 60, 805 (1838). (2) For references and discussion see K . Hedberg, hl. E. Jones, and V. Schomaker, Pmc. A ' d Acad. Sci. t'.S., 38, 679 (1952). (3) K. Hedberg, V. Schomaker and M. E. Jones, Paper E.D. 17, Second International Cungess of Crystallography, Stockholm, June 27-fuly 5 , 1951 The structure. althongh not mentioned i n the Ahstract, was presented at the meeting. (4) Quarterly Progress Report, October 23, 1951, Contract NBonr 24423.
d 6 .
Fig. 1.-The
molecular structure of B ~ H I O .
Aug. 20, 1953
COMMUNICATIONS TO THE EDITOR
4117
record average bond distances with their average deviations on the assumptions that the molecular symmetry is Czvand that the two B'-H and the four BU-H distances are all equal. Molecular parameters' are four B'-B" = 1.845 f 0.002&, B'-B' = 1.750A., B"-B" = 2.786A.) six B-H = 1.11 0.04, four B'-Hb (bridge) = 1.21 f 0.03A. and four B"-Hb = 1.37 f 0.108. Assuming a boron radius of 0.75i%., and therefore ?ingle bond distances of 1.50A. for B-B and 1.lOA. for B-H, bond orders are 0.27 for B'-B", 0.38 for B'-B', 0.01 for B"-B", 0.96 for B-H, 0.65 for B ' - H b and 0.35 for B r ' - H b . The total bond order for the molecule is thus 11.2, close to the expected value of 11. The assumed boron radius is smaller than that calculated for BzHe (O.79Ai.), BbHg (0.788.) and &OH14 ( O H ) ,and as in B6H9 the over-all size of the molecule is smaller than that reported in the preceding electron diffraction study by Jones, Hedberg and Schomaker. A similar effect has been observed in BsHg and in hexamethylenetetramine. It is of interest that the B"B'B" bond angle is 98" which is a value about midway between the corresponding angle of 90" in the octahedron and 108" in the icosahedron. Thus the boron arrangement may be regarded as a fragment from either the octahedron or the icosahedron. The relatively open structure of this, the first member of the B,H,+e series compared with the relatively compact higher B,H,+d structures, probably is a factor relating to the comparatively greater reactivity. Support of this research by the Office of Naval Research is gratefully acknowledged. All of the three-dimensional Fourier syntheses were carried out on the X-Ray Analogue Computer a t Pennsylvania State College through the courtesy of Professor R. Pepinsky. We are also indebted to Dr. L. V. McCarty of the General Electric Company for supplying us with a sample of pure B4H10. Details of this investigation will be submitted elsewhere.
adrenal cortical hormones, especially in view of the report by Ehrenstein' that an amorphous product, believed to be a 19-nor-desoxycorticosteroneisomer and obtained by a lengthy degradation from strophanthidin, was devoid of biological activity. In this communication we record the synthesis and physiological activity of 19-nor-desoxycorticosterone (IIIb), which possesses the same configuration a t all asymmetric centers as does desoxycorticosterone.
(1) Sterolds. XLWI, C. Djerrssf, L. Mirarnontes and G. Xosenkrane, 73118JOVRNAL, 'le, November (1958). (2) L. Miramontea, G. Rosmkran2 and C. Djmad, (bdd., 78, 25-40
Nelson, T H I SJOURNAL, in press. (6) Cf.L. Ruzicka and P. M(iller, H c k Chim. Acto, 38, 765 (1989). (7) Cf.A. Serini and W. LogemPnn, B e . , 71, 1882 (1938). ( 8 ) Inter al. A. Serini, W. Logemann and W. Hndcbrand, ibid., ?P, 391 (1939); 6 ;D ~ W U Bpad S ~ C. a.Scholdc, Trim I o ~ ~ A71, AL 8982 ., (1949).
OH
I
I1 CHzOR
I c=o I
Chromic acid oxidation of 19-nor-testosterone6 yielded 19-nor-A4-androstene-3,17-dione [m.p. 171172", [ a ] " ~+139" (CHC13)) XE2H 240 mp, log E 4.24. Calcd. for CleHz40z: C, 79.37; H, 8.88. Found: C, 79.39; H, 8-99] which upon conversion [m.p. to 19-nor-3-etho~y-A~~~-androstadien-17-one ~ (pyridine), XEzH 242 mp, 141-143O, [ a l Z o-87" log E 4.26. Calcd. for CzoHzsOz: C, 79.95; H, 9.39. Found: C, 79.80; H, 9.151, ethinylation with potassium in t-amyl alcohol and acid hydrolysis furnished 19-nor-17-ethinyltestosterone(I) [m.p. 203-204", [(rlZoD -25' (CHC13), hz\:H 240 mp, log E 4.24. Calcd. for CZOHZ~OZ: C, 80.49; H, (1) Where the distance is observed more than once we record 8.78. Found: C, 80.83; H, 8.801. Partial hydroaverage deviations, which are comparable with estimated probable genation in pyridine solution over a 5% palladiumerrors, except for B'-B" for which a probable error of *0.01 A. is calcium carbonate catalyst6 led to the correspondestimated. ing vinyl carbinol I1 [m.p. 169-170", [ ( r I z 0 ~$25" SCHOOL OF CHEMISTRY :\ 240 mp, log E 4.25. Calcd. for UNIVERSITY OF MINNESOTA CHRISTERE. NORDMAN(CHC13), XzH MIXNEAPOLIS 14, MINNESOTA WILLIAMN. LIPSCOMB CZOHZSOZ: C, 79.95; H, 9.39. Found: C, 79.64; RECEIVED JUNE 30, 1953 H, 9.271. This latter compound was hydroxylated with osmium tetroxide,' and the product without purification was acetylated and subjected to 3 XLIX.' 19-NOR-DESOXYCORTICOS- Serini reaction in toluene solution.8 The resulting STEROIDS. TERONE, A POTENT MINERALOCORTICOID HOR- 19-nor-desoxycorticosterone acetate (IIIa) [m.p. MONE 169-171", [ a I z 0 D $153' (CHC&), 240 mp, Sir : log E 4.26, infrared bands (chloroform) at 1744 and 19-Nor-progesterone, 19-nor-17-methyltestos- 1718 cm.-' (21-acetoxy-20-ketone) and 1668 cm.-' teronej3 and 19-nor-17-ethinyltestosterone (I)3 (A4-3-ketone). Calcd. for C22H3004:C, 73.71; have all been shown to possess biological activity H, 8.44. Found: C, 73.88; H, 8.231 was saponiof a higher order than the parent hormones. It fied with sodium bicarbonate in aqueous methanol was therefore of considerable interest to make avail(4) M. Ehrenstein, J . #g. Chm., 8, 485 (1944). able for biological testing the 19-nor analogs of (5) A. J. Birch, J . Chem. Soc., 367 (1950); A. L. WildsandN. A. (1951).
(3) C. D j 4 , 1. Mh.5unte.8 pad 0.Izasaakrnaz, Alastracts, 121st Meeting of the Am. 6hem. Bee., MUnaulm, 195%
