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Crystal Structure of Carbonyl-(piperidine-N-carbonitrile)nickel(0).

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The pentacyclic hydrocarbon C14H20, which crystallizes in
optically isotropic octahedra. m.p. 237 "C, on slow sublima(3),
tion, is pentacyclo[]tetradecane
which was recently synthesized [31 and called diamantane [41
(originally songressane [31). The hydrocarbon C14H20 and
authentic diamantane have the same melting point, an undepressed mixed melting point, and the same elution times
on gas chromatography. The mass spectra also are identical
and correspond[**] with the published mass spectrum of
diamantane [31.
Received: October 6th. 1966
[ Z 345 IE]
German version: Angew. Chem. 78, 1060 (1966)
[*I Determined by gas chromatography (capillary column);
mass spectrometry indicates that the impurities are predominantly
hydrocarbons C12H20, C13H22 (alkyladamantanes), and C13H20.
[l] S. Landa and V . MachuCek, Collect. czechoslov. chem.
Commun. 5, 1 (1933).
[2] S. Hula and S. Landa, Erdol Kohle-Erdgas-Petrochem., 19,
727 (1966).
[3] C. Cupas, P . v. R . Schleyer, and D . J . Trecker, J. Amer. chem.
SOC.87, 917 (1965); cf. Angew. Chem. 77, 180 (1965); Angew.
Chem. internat. Edit. 4, 169 (1965).
[4] 0. Vogl, B. D. Anderson, and D. M . Simons, Tetrahedron
Letters 1966, 415.
[**I The ratio of the abundance of the molecule ion to that of
the commonest fragment (m/e = 91) is, however, twice as great
as in the published spectrum [3].
Crystal Structure of Carbonyl-
The dimension of the unit cell are
a = 12.28
b = 9.33
c = 12.31 b,
01 =
p = 109.5
y = 82.4"
Volume (1278 83) and formula weight (196.9) lead to the
density D(ca1c) = 1.54 g/cm3 whereas D(obs) = 1.53 g/cm3.
1594 reflections (CuK,) were registered at room temperature
on film, and intensities were measured photometrically 17-1.
Observable intensities were found only in the range of
0 "-45 "(overall temperature factor Bo N 6 A2). Coordinates
of the Ni atoms could be found from a sharpened Patterson
synthesis. Those of the light atoms (21 C, 6 N, 3 0) were
found on successive Fourier syntheses and refined by leastsquares methods, the R factor decreasing from 45 % to 16 %.
Received: October loth, 1966
[Z 347 IE]
German version: Angew. Chem. 78, 1064 (1966)
By Dr. K. Krogmann and Dr. R. Mattes
Laboratorium fur anorganische Chemie,
Technische Hochschule Stuttgart (Germany)
The crystal structure of carbonyl(piperidine-N-carbonitrile)
nickel(O), Ni(C5HloNCN)(CO), first prepared by H. Bock
and H . tom Dieckcll reveals a new type of r-complex, involving C = N triple bonds.
Six formula units are contained in the triclinic unit cell
(space group P1) as two trimeric molecules. The nickel atoms
of each trimer occupy the corners of a n equilateral triangle, all having the same coordination of light atoms. Two
nickel atoms (Ni-1 and Ni-2) are relatively close to nickel
atoms of the adjacent trimer (3.20 A), but no effect of metalmetal bonds o n the coordination sphere can be detected.
The figure shows a projection of the molecule on the plane of
the three nickel atoms. Essential bond distances and angles
(averaged) are included. All atoms of the CO and N C N
groups are in the plane of the three Ni atoms or deviate
from it by less than 0.3 A. Every Ni atom is linked by o
bonds to a carbonyl-C and a cyano-N. Three of these monomers form the trimer using x-bonds from the cyano groups.
There are no >N=C=NR2 groups; these would be linear
and perpendicular to the line Ni-Ni. Bond distances and
angles are instead in accordance with -N E C - N R ~ groups,
and N and C atoms of the C N groups are equidistant from
the x-bonded Ni atom (1.99 A). The bond angles
might be expected as a result of the displacements of electron density in the x-system of the N = C
group. The N atom of piperidine is not involved in bonding
to Ni. The rings have the chair conformation; two C N
groups are attached axially, and one is attached equatorially.
[l] H . Bock, Angew. Chem. 74, 695 (1962); Angew. Chem. internat. Edit. I , 550 (1962); H . Bock and H . tom Dieck, Chem. Ber.
99, 213 (1966).
[ 2 ] Crystals were kindly supplied by Drs. H . Bock and H. tom
Preparation of Phosphorus Tribromide from the
By Dr. F. Schroder
Institut fur Anorganische Chemie,
Universitat Hamburg (Germany)
Preparation of PBr3 from the elements has hitherto required
white phosphorus and/or use of a solvent[l*zl, as well as
complicated apparatus [21. We have now converted red
phosphorus into PBr3 with bromine in the absence of a
solvent, using a three-necked, round-bottomed flask (1 liter)
equipped with a dropping funnel, a reflux condenser with
drying tube, and a stirrer with a glass precision bearing. Red
phosphorus powder (2 g-atoms) is very gently stirred and
treated dropwise with 3 moles of bromine, slowly at first,
then faster. The PBr3 formed may contain suspended phosphorus and is distilled off. Water cooling can be used until
the liquid PBr3 appears. Previous passage of purified nitrogen
through the apparatus and drying of the phosphorus avoids
formation of small amounts of PzO5.
[ Z 346 IE]
Received: October llth, 1966
German version: Angew. Chem. 78, 1102 (1966)
[l] Gmelins Handbuch der anorganischen Chemie. 8th. Edit.,
Verlag Chemie, Weinheim 1965, System No. 16, Part C.
[2] Inorg. Synth. 2, 147 (1946).
Angew. Chem. internat. Edit. / VoI. 5 (1966) / No. I2
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crystals, nickell, structure, carbonyl, piperidines, carbonitrile
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