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Anionic Heterosiloxanes.

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A combination of plant materials, discussed in ancient
Indian medical literature, blocks the estrogen-induced
increase in enzyme activity [172]. Experiments with mice
have shown that nidation can also be prevented by upsetting the endocrine equilibrium needed for this process [173]. Induction of unphysiological motility of the
genital tract before nidation has occurred greatly decreases the viability of the embryo (cf. Table 5).
The question remains whether the anaerobic metabolism
which prevails at the beginning of the second regulatory cycle
and which provides an optimum milieu for fertilization can
be affected in any way. This in turn would modify some of the
functions in the female genital tract needed to effect conception; for example, the production of antiagglutinins and“fertilisins” needed for capacitation of the sperm might be affected.
It has been possible to produce an antigen from sperm
and also antiserum against spermatozoa of different
species [174].
It is not yet possible to foretell the practical significance
of the many measures discussed in this article. As yet
there is competition on the one hand between contraceptive measures that interfere with certain of the mechanisms of conception and mechanical devices, and, on
the other, between these and attempts t o determine the
nonfertile period in the second regulatory cycle (e.g. by
means of the Knaus and Ogino calendar, by measuring
the vaginal temperature in the morning in order to determine the postovulatory rise in temperature caused by
progesterone, or by pregnanediol determination according to Reimann - Hunziker and Wild [175]). On
the basis of statistics, it can be asserted that, when
properly used, gestagens that inhibit the sex center and thereby prevent ovulation have the greatest
contraceptive potentialities and reliability (practically
100 %).
Received, January 24th. 1962 [A 225/47 IE]
[I721 H . S. Chakravarti, J. Indian med. Assoc. 37,322 (1961).
11731 H. M . Bruce, J. Reprod. Fertility 2, 138 (1961).
[I741 A . S.Parkes, J. Reprod. Fertility 3, 158 (1962).
[I751 R . Reimann-Hunziker and W Wild,Med. Klinik 57, 440
(1962).
COMMUNICATIONS
Anionic Heterosiloxanes [ l l
By Dr. H. Schmidbaur and Prof. Dr. Max Schmidt
Institut fiir Anorganische Chemie
der Universitat Marburg/Lahn (Germany)
The siloxyl groups forming coordination bridges between
two metal atoms in the dimeric tris-trimethylsiloxy compounds (I) of Al and Ga [2] account for the great readiness
with which these compounds add on metal siloxides (11).
Even at room temperature, equimolar mixtures of solutions
of { [(CH3)3SiOl3A1}2 or { [(CH3)3SiO]3Ga)z and NaOSi(CH&
or KOSi(CH3)3 in CC4 yield white precipitates of the
sodium or potassium tetrakis-trimethylsiloxy-alanates (111)
or -gallanates (IV) in an exothermic reaction, e.g.
SiR,
RsSi
I
‘o\AI/o\A,/o
/ \o/ \o
RaSi/ O
S~R,
I
PR3
+ 2 R,SiOeM@ 4
'Sib
(11)
(1)
(M = Na or K ; R = CH3). These sodium and potassium salts
are insoluble in organic solvents, and begin to decompose
slowly at temperatures above 250 “C. Their infrared spectra
in Nujol show bands, whose positions prove the existence of
discrete anions (v Si-0-A1 at 10.35 p and v Si-0-Ga at
10.80 p). Analogously prepared lithium salts are soluble in
organic solvents, are fusible, sublime in vacuo, and have
infrared spectra unlike those of the Na and K salts. The
spectra of the Li compounds indicate a strong homopolar
linkage of the metal to the anion, as well as the presence
of molecular association, which is further confirmed by
molecular weight determinations. The proton magnetic
Angew. Chem. internat. Edit. / Vol. I (1962)/ No. 10
resonance spectra in CC4 show only one sharp resonance
singlet, which is an impressive proof of the equivalence of all four siloxyl groups (chemical shift for
Li(Al[OSi(CH3)3]4),-0.125 ppm; for Li(Ga[OSi(CH&I4),
-0.165 ppm [3].
The anions of 111 and IV are isosteric with the neutral siloxanes Si[OSi(CH3)3]4 and Ge[OSi(CH3)314, for example:
R3Si
/SIR3
‘0
\cia/’
\o
- R3Si/O
‘SiR3
(JW
I‘
R3Si
PiR3
O
\
and
\Ge/O
/
R3Si/ O
\o
‘SiR,
B.p. 59-6O0C/1 mm.; m.p. -59°C [41
Their infrared and proton magnetic resonance spectra show
the complete structural identity of the tetrahedral ionic and
neutral siloxane compounds. With analogous “complex
silicones”, where iron was the heteroatom, we obtained
similar results [l].
Received, June 22nd. 1962
[Z 305/139 IE]
[I] Heterosiloxanes,Communication X.-Communication IX : H.
Schmidbaur and M . Schmidt, J. Amer. chem. SOC.,in press.
[2J H. Schmidbaur and M . Schmidt, Angew. Chem. internat.
Edit. I, 328 (1962).
[3] Varian A 60 (60 Mc); solutions of all substances in CC14 at
c = 5 i 1%, with tetramethylsilaneas internal standard.
[4] First prepared by us from GeC14 and four moles of
NaOSi(CH3)s in anhydrous ether.
Bis(tripheny1phosphe)-ethylene-nickel
and Analogous Complexes
By Priv.-Doz. Dr. G. Wilke and Dip1.-Chem. G. Herrmann
Max-Planck-Institut fur Kohlenforschung
Mulheim/Ruhr (Germany)
By the interaction, at approx. 20 “C,of nickel acetylacetonate
with (CzH&AIOC2Hs in the presence of triphenylphosphine
(TPP) (Ni: P = 1 :2) in benzene, bis(tripheny1phosphine)ethylene-nickel, (TPP)ZNi.C2H4) is produced in yellow
549
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