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Novel Polycyclic Phosphanes and Arsanes P11(SiMe3)3 and As7(SiMe3)3.

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Pi,(SiMe& and As7(SiMe&
By Hans Georg von Schnering, Dieter Fenske, Wolfgang
Honle, Michael Binnewies, and Karl Peters"]
From the products formed on reaction of Na/K alloy with
white phosphorus and chlorotrimethylsilane in monoglyme
Fritz and Holderich['l were able to isolate polycyclic phosphane derivatives such as P7R3,
and P13R5 ( R = SiMe,)
in yields of up to 40% P. We have now found that reaction of
the pure phosphides Na3Pll and Cs3Pt1and of the arsenide
Rb3As7with chlorotrimethylsilane in toluene leads in a surprisingly simple way and in high yields to Pl,(SiMe3), and
A s ~ ( S ~ Mrespectively.
P,,(SiMe3)3: When a suspension of 20 g of Na3Pl1121
Cs3PtI [3.41(previously finely ground under inert conditions)
in 02-free toluene is treated with an excess of Me3SiC1 and
the vigorously stirred mixture is heated under reflux for two
days, deep yellow-orange solutions are obtained from which
NaCl and CsCl, respectively, separate out. After filtration,
removal of Me3SiC1and half of the toluene, and cooling to
O"C, Pll(SiMe& crystallizes in ca. 60% yield (based on P,
not optimized).-In the preparation of Na3Pl and Cs3Pl
often Na3P7 and CS~P,[~I
are also formed; in this case large
amounts of P7(SiMe3)3are also obtained.
As,(SiMeJ,: An analogous reaction is carried out with
about 30 g of Rb3As7 (described in the system Rb/As as
though at room temperature and in the absence of
light. A deep-red solution is obtained. After 24 hours, removal of RbCl by filtration, concentration of the filtrate to 50%
of its original volume and cooling to 0 "C leads to crystallization of A ~ , ( s i M e ~in) ~
70% yield.
4,7,11 -Tris(trimethylsilyl)pentacyclo['0.05~9]~ndecaphosphane, P1,R3, forms bright-yellow flat rhombic
(lentil shaped) crystals which are much more reactive (H20,
than P7R3,both under the mother liquor as well as in the
isolated form. The mass spectrum (QMS) at 150°C shows
fragments differing from one another by P2 or P4 units [rn/e;
abundance]: PIIR: [560; 661, P,R; [498; SO], P7RZ [436; 181,
P7R; [363; 771, P,R: [312; 201, P'R; [301; 1001, P4R; [270;
301, PR; [250; 451, P3R; [239; 951, P,R; [208; 951.
Of these, P,R; seems noteworthy to us as a possible derivative of a P, prism[''; it has also already been observed by
Frirz and Holderichl''. At T>200"C we also found a small
amount of Pt6R; [rn/e= 6421. PItR3crystallizes monoclinically in the space group P2,/c (No. 14) with a = 1912.8(8),
b = 1137.8(5), c = 1227.3(9) pm, p =90.73(4)", Z = 4 . The
structure determination is not yet complete, since the isolated
crystals rapidly decompose. The molecular structure is, however, confirmed (390 hkl; R =0.15). The asymmetrically substituted enantiomers of the "ufosane" polycycle Pi; ['] are
present with mean P - - P distances of 221.5 pm (Fig. 1,
3,5,7-Tris(trimethylsilyl)tricyclo[2.2.1 .02,6]heptaarsane,
As7R3, forms bright-yellow rhombohedra1 crystals up to 2
mm in length which are astonishingly air-stable in the isolated state. On exposure to moisture, air, and light, arsenic
separates out after a few hours (in the mother liquor, immediately). Its solubility in toluene is lower than that of PlIR3.
The mass spectrum at 80°C shows As7R; [744; 711, As4Rf
[519; 291, As3R; [444; 1001, and As: [300; 851. As7R3crystal[*I
Fig 1 Structures of the silyl-substituted polycyclic undecaphosphane P, ,R, and
of the heptaarsane As7R3(R=SiMe?)
lizes rhombohedrally in the space group R3 (No. 148) with
aR= 1298.9(3) pm, a = 50.29(1)', Z= 2 (aH= 1103.8(3),
cH= 3395.4(9) pm, Z = 6). The structure determination (1721
hkl; R = 0.05) confirms the expected configuration of the homologs P7R3['](Fig. 1, below). The As As bond lengths are
A=244.4(2), B=242.7(2) and C=240.7(1) pm [As Si
= 239.7(3) pm]; the sequence A > B > C corresponds to that
observed in P7R3l7]and differs from the sequence A >C > B
in the anion As:-[81.
Received June t 1. 1979 (Z 274b IE]
German version Angew Chem 91, 755 (1979)
G. Fritz, W. Hblderich, Nalurwissenschaften 62, 573 ( 1 975).
W. Wichelhaus, H. G. u. Schnering, Natunvissenschaften 60, 104 (1973).
W. Bues, personliche Mitteilung ( 1 978).
H. G. v. Schnering el al., to be published.
H. G. u. Schnering "Catenation of Phosphorus Atoms" in A. L. Rheingold:
Homoatomic Rings, Chains and Macromolecules of Main-Group Elements.
Elsevier, Amsterdam 1977.
[6] S. Lohmeyer. Dissertation, Universitat Munster 1962.
[7] W Honle, H. G. u. Schnering, Z . Anorg. Allg. Chem. 440, 171 (1978).
181 W Schmelrow, H. G. u. Schnering, Angew. Chern. 89, 895 (1977); Angew.
Chem. Int. Ed. Engl. 16, 857 (1977).
Synthesis, Resolution, and Characterization of an
Aminophosphane Rotamer Pair[**]
By Otto J. Scherer and Michael Piittmann["
On introduction of two different bulky substituents R', R2
of the kind X(CH3), (X = C, Si, Ge), in addition to sterically
active groups R, into aminophosphanes['"l and -arsanes[lbI
(EI=P, As), a pair of rotamers can be detected by NMR spectroscopy[']; however, their resolution has
so far proved impossible.
On reaction with a N,N'-bismetalated diaminosilane
R/ 'YLi
- 2 I.,( I
c R, ,P;(CR,)SiR3
y ,ps
R = CH,
Prof. Dr. H. G . von Schnering, Dr. W.Honle, Dr. K. Peters
Max-Planck-Institut fur Festkorperforschung
Heisenbergstrasse I , D-7000 Stuttgart 80 (Germany)
Priv.-Doz. Dr. D. Fenske. Dr. M. Binnewies
Anorganisch-chemisches Institut der Universitat
Gievenbecker Weg 9, D-4400 Miinster (Germany)
I**] This work was supported by the Fonds der Chemischen Industrie.
Angew. Chem. Int. Ed. EngI. 18 (1979) No. 9
Prof. Dr. 0. J . Scherer, DipLChem. M. Piittmann
Fachbereich Chemie der Universitat
Postfach 3049, D-6750 Kaiserslautern (Germany)
0 Verlag Chemie, GmbH, 0940 Weinheim, 1979
$ 02.50/0
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p11, as7, arsanes, phosphane, novem, sime, polycyclic
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