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Ge38P8I8 and Ge38As8I8 a New Class of Compounds with Clathrate Structure.

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figuration of the central atom exceeds the inert gas configuration by one electron in the paramagnetic complex studied.
This electron could have a weakening effect on the bonding. Further structural studies are in progress to clarify
these questions.
Received: August 25,1971 [Z 517 IE]
German version: Angew. Chem. 84, 29 (1972)
G . E . Herberich, G . Greiss, and H . F. Heil, Angew. Chem. 82, 838
(1970); Angew. Chem. internat. Edit. 9, 805 (1970).
[2] A J . Ashe and P . Shu, J. Amer. Chem. SOC.93, 1804 (1971).
Fig. Molecular structure of bis(methoxoborinato)cobalt.
Table. Interatomic distances and angles in bis(methoxoborinato)cobalt.
Distances (8,)
B -C(1)
B -0
c o -C(1)
co 4 2 )
c o -C(3)
B -(C(5)
0 -C(11)
C o -C(5)
Co -C(4)
Co -B
1.525 k0.007
1.394 +0.009
1.418 0.009
2.248 iO.005
2.164 i0.006
2.057 k 0.006
2.141 +0.006
2.348 kO.007
Angles (‘)
114.8 k0.5
B -0-C(l1)
[3] G . E. Herberich, G. Greiss, H . F. Heil, and J . Muller, Chem. Commun. 1328, 1971; single crystals were kindly provided by Dipl.-Chem.
H . F . Heil, Munchen.
[4] Measurements by DipLChem. H . F . Heit.
[S] M . R. Churchill and F. R . Schoter, Inorg. Chem. 8,1950 (1969).
[6] A review is to be found in ref. [S].
[7] D. S t . Clair, A . Zalkin, and D. H . Templeton, Inorg. Chem. 8, 2080
[8] H . Hess, Acta Crystallogr. B 25, 2334 (1969), found a value of
1.583 8, for the B,,,-C,,,
single bond length in 1,3,5-tris(dimethylamino)-l,3,5-triboracyclohexane. The difference of 0.03
the covalent radii of C,,, and C,,, leads to an estimate of 1.55 for a
single bond length which is in good agreement with the
B-C distance in p-bromophenylboronic acid of 1.54 .&: Z . V: Zuonkova
and P . Gluskoca, Kristailografia, USSR, 3, 559 (1958) (Engl. Edzt. :
Crystallography 3, 564 (1958)).
[9] V: F . Ross and J . 0. Edwards in E. L. Mutterties: The Chemistry of
Boron and its Compounds. Wiley, New York 1967, p. 196.
Torsion angles (“)
B -C(5)-C(4)-C(3)
- 5.6
C(1)-B -C(5)-C(4)
The cobalt-ligand bond lengths vary systematically : The
distance from the metal to the “central” carbon atom
co-c3 (2.05710.006 A) is the shortest, the bonds to the
atoms C 2 and C 4 (mean value 2.153k0.011 A) are considerably longer but still shorter than the distance to the
“terminal” carbon atoms C 1 and C 5 (mean value 2.240
+O.OOSA). This pattern of distances arises because the
metal atom is displaced away from the boron atom toward
the carbon atom C3. Added to this effect is the slight
puckerin? of the ring. The cobalt-boron distance (2.348
kO.008 A) is the longest metal-ring distance in the complex. Although considerably longer than the Co--B distances in carborane complexes[71it is certainly still within
the range of a strong cobalt-boron interaction and thus
indicates participation of the boron in complex bonding.
The distance between the boron and the ring carbon atoms
C 1 and C 5 has a mean value of 1.523k0.008 A and is
therefore only slightly shorter than a Bsp2-Csp2 single
bondca1.The B-0 distance of 1295 +0.007 A corresponds
to the bond length of 1.37i0.02 A that is typical for trigonal
berates['], thus indicating considerable double bond
The bonding in complex (1) is not necessarily typical for
the complexing behavior of a borinato ligand : The
methoxo substituent on the boron atom could exert a
significant influence on the structure; the electronic conVol. I1 (1972) 1 No. i
Ge,,P,I, and Ge,,As,I,, a New Class of
Coqpounds with Clathrate Structure
2.3 ; in cyclohexadienyl-metal complexes the corresponding angle is about 40”[61.It therefore appears that the boron
atom, in contrast to the methylene group in cyclohexadienyl complexes, participates in metal-ligand bonding.
Angew. Chem. internat. Edit.
By Hans-Georg von Schnering and Heinz Menke“’
Preparations of germanium phosphides under the conditions of chemical transport reactions with I, as transport
vehicle[’] yielded small amounts of cubic crystals whose
X-ray structure analysis showed them to be Ge,,P,I,.
In order to prepare pure samples of the isotypic compounds Ge,,P,I, ( I ) and Ge,,As,I, (Z), stoichiometric
amounts of the elements are heated in a quartz ampoule,
the starting materials being kept at 900°C. After a few
days the products (1) and (2) respectively deposit as
well formed crystals in the colder part of the ampoule
(800°C). The hard and brittle crystals, which have a
silvery metallic sheen, are stable to attack by water and
dilute acids and alkalis ; they rapidly dissolve, however, in
oxidizing alkaline melts. The synthesis is favored by a
small excess of iodine because slight amounts of GeI,
are invariably formed (readily removed with H,O).
Otherwise crystals are obtained which have a yellow, red,
green, or blue tint.
In a vacuum, compound ( I ) is degraded to germanium
between 550 and 650°C. No information could be obtained
about possible intermediates such as germanium phosphides”]. In the mass spectrum the fragments I + , P;,
and P,‘ are not recorded at temperatures below U0°C[31.
Compounds (1) and (2) form cubic cry2tals of space
group P43n-T: witha= 10.507and 10.611 A, respectively.
The atoms of Ge,,P,I, occupy the following positions :
24 Ge(1) in 24(i) with x = -0.0027, y=0.1190, z=0.3069;
6Ge(2) in 6(c); 8Ge(3) in 8(e) with x=O.1841; 8 P in 8(e)
with x=O.8148; 61(1) in 6(d) and 21(2) in 2(a) [225
Prof. Dr. H.-G. v. Schnering and H. Menke
Anorganisch-chemisches Institut der Universitat
44 Miinster, Gievenbecker Weg 9 (Germany)
reflections hkl, diffractometer data, Mo,, radiation,
R =0.068]. The 38 Ge atoms and the 8 P atoms together
form a tetrahedral skeleton having (6 + 2) large cavities
that are occupied by I atoms. The structure is thus completely analogous to those of the gas hydrates of type
Xe.5.75 H,O D<es(H,0)46] or the correspondingly built
phases K,Ge,,, etc.I4] in which the cavities are occupied
by Xe and K respectively. The Ge and P atoms are arranged
regularly in the E46 skeleton: Every P and every Ge(2)
is bound to four Ge neighbors, every Ge(1) and Ge(3)
to three Ge and one P neighbors (Ge-Ge= 2.45 - 2.50 A ;
Ge-P = 2.38 - 2.40 A). The distances 10 the I atoms are
3.57-3.9OA for I(1) and 3.35-3.46A for I(2). On the
basis of their tetrahedral coordination and electron
balance the P atoms can be regarded as phosphonium
ions P+ and the two compounds ( I ) and ( 2 ) characterized
by the formulas Ge,,P:I,
and Ge,,AszI; (compare
also the large distances between the iodine atoms). If
these views are correct then the compounds should be
semiconductors. Conductivity
and attempts to extend this novel class of compounds by
variation of the main group elements are currently in
Received August 30,1971 [Z51 X IE]
German veision: Angew. Chem. 84,30 (1972)
[I]H . Schufer: Chemische Transportreaktionen. Verlag Chemie,
Weinheim 1962; Academic Press, New York 1964.
[2] Experiments by C . Brendel, Miinster
[3] Experiments by K . Rinke, M. Binnewies, and H . Rubeneck, Miinster.
[4] J . Gallmeier, H . Schufer, and A . Wezss, Z. Naturforsch. 246, 665
[5] Jointly with A . Rabenuu, Stuttgart.
analogous fluorene derivativesl41: They are transformed
into isomeric hydrocarbons only after several hours' heating at 100°C.
The NMR spectrum in CS, at 38°C exhibits peaks at
z= 2.90 (4H/m) ; 3.49 (1 H/d), J = 5.4 Hz ; 3.72 (4H/m) ;
3.90 (1H/d), 3=5.4 Hz; 5.88 (2H/m). The peaks at z=2.90,
3.49, and 3.90 are due to the aromatic protons and the
protons on C-3 and C-2 in the indene part of the molecule.
The signals at z=3.72 and 5.88 are the time-averaged
signals of the B,y-protons and the a-protons, respectively.
The position of the a-proton signal itself evidences a
fluctuating norcaradiene-cycloheptatriene sy~tem[~I.
multiplet at r=5.88 is shifted downfield by a rise in temperature and upfield by drop in temperature, as expected
for a low-energy norcaradiene component. Marked broadening is observed, above all for the signals at T = 5.88 and
3.72, below -80°C; at - 105°C the signal at highest field
is only just recognizable. The individual isomer spectra,
which could provide information about the stereochemistry
of ( 2 a ) , could not be observed.
The position of the averaged a-proton peak (z=5.88) at
room temperature and the expected position of the aproton signals in ( 2 a ) and ( 2 b ) (r=4.8 and 7.0)[41afford
a ratio of ca. 1: 1 for the valence tautomers. In contrast, the
equilibrium lies predominantly on the norcaradiene sidec6]
in the corresponding cyclopentadiene system at room
temperature, and preponderatingly on the cycloheptatriene side in the fluorene system[41.The preference for the
cycloheptatriene form with increasing degree of ring fusion
can be explained in terms of likewise increasing steric
hindrance in the norcaradiene form.
1-Diazoindene ( I ) :
A mixture of indene (58 g) and diethylamine (100 ml) are
treated at 0°C with tosyl azide (98.5g) and allowed to
stand for ca. 70 h at 0°C. To the deep red mixture is added
By Dieter Rewicki and Christian Tuchscherer"]
water (250ml) and the mixture is extracted with light
Unlike 5-diazo~yclopentadiene[~~
and 9-diazofl~orene[~~, petroleum (40-80°C) until the extract is only yellow. The
I-diazoindene ( I ) has not hitherto been isolated. We have
combined extracts are washed with water ( 5 x), dried over
now prepared ( I ) by reaction of tosyl azide with indene in
Na,S04, and concentrated in vacuum. The resulting deep
diethylamineL3! Diazoindene is stable indefinitely below
red liquid is fractionally distilled under N, in 50-ml por0°C and can be chromatographed and distilled without
tions over a short Vigreux column: At a bath temperature
of 50--70°C unreacted indene distills over under oilpump vacuum, and on evacuation with a Hg-diffusion
pump diazoindene ( 1 ) (b. p. 80-95 "C) is collected in the
receiver. (Caution! At a bath temperature in excess of
120°C the contents of the distillation flask, predominately
tosyl azide, decompose explosively.) Distillation over a
10-cm Vigreux column furnished 10.3 g of ( I ) as a dark-red
oil of b. p. 67°C/10-3 torr; yellow-red crystals of m.p.
23-25"C(frompetroleum ether), yield 15%.NMR(CC1,):
~=2.1-3.1 (4H/m); 3.23 (1 H/d), J=5.5 Hz; 3.78 (1 H/d);
J = 5.5 Hz. IR (in CCl, and CS,) : 3660,3075 (w),2068 (vs),
1469 (w), 1420 (s), 1380, 1307, 1212, 1207, 1088 (w), 761,
750, 702 cm-' (m). UV/visible (in n-heptane): 490 (1.27),
328 (4.066), 265 (4.261) nm (log&).MW: 142 (determined
by mass spectrometry).
1-Diazoindene and Spiro[indene-l,7'-norcaradiene]
Photolysis of diazoindene (1) in benzene gives a 45% yield
[based on reacted ( I ) ] of spiro[indene-I,7'-norcaradiene]
(2 a ) which is in rapid equilibrium with spiro[2,4,6-cycloheptatriene-1,l'-indene] ( 2 b ) . The valence tautomers
( 2 a ) C ( 2 6 ) have comparable thermal stabilities with the
Prof. Dr. D. Rewicki and Ch. Tuchscherer
Institut fiir Organische Chemie der Freien Universitat
1 Berlin 33, Thielallee 63/67 (Germany)
Spiro[indene-l,7'-norcaradiene] + spiro[2,4,6-cycloheptatriene-l,l'-indene] ( 2 a ) ( 2 b ) :
Diazoindene ( I ) (6.6 g) in anhydrous benzene (300 ml) is
irradiated in a quartz recycling apparatus for 20 h with a
150-W high-pressure mercury arc lamp. During this period
60% of the calculated amount of N, is evolved. The benzene
is evaporated off under vacuum and the residue chromatoAngew. Chem. internat. Edit. Val. 11 (1972) 1 No. 1
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class, structure, compounds, clathrate, ge38p8i8, new, ge38as8i8
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