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Infrared Spectroscopic Investigations on Methylenetriphenylphosphoranes.

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tenfold amounts of methanol and 30 % acetic acid and left
for 4 h in order to remove the trimethylsilyl groups. This
mixture is then shaken with chloroform, and the aqueous
phase is evaporated to a sirup in vacuum. The latter is
dissolved in five times its weight of 10 sodium hydroxide.
The solution is cooled in ice, and 10% of its volume of 3 0 %
hydrogen peroxide is added. After 3 h at room temperature,
the sodium ions are removed with a Dowex 5 0 cation exchanger, and a trace of platinum oxide is added to decompose
the excess peroxide. The aqueous solution is evaporated to
dryness and the boric acid is removed by repeated distillation
with methanol. The residue, which begins to crystallize, is
taken up in a little hot ethanol; on cooling, (3) crystallizes out.
The mother liquor is chromatographed on Whatman No. 4
paper with n-butanol/propionic acidlwater (142:71: 100 v/v,
descending), and the zones of (3) and (4) at Rf 0.50 and 0.65
are cut out and eluted with water. The overall yield of (3)
plus (4) is 85-90 %. The solution containing (4) is concentrated to a sirup and heated for 6 h with 1 N sulfuric acid on
a steam-bath. Removal of the acid with an Arnberlite IR 45
anion exchanger and concentration of the aqueous solution
leads to [5-3H]-~-idosan,which has the same paper- and gaschromatographic properties as D-idosan [3]. It was proved
by degradation [4]of ( 3 ) that the tritium is located on C-5.
formula (2). The type of bonding between the phosphorus
and the methylene-carbon should be recognisable on comparison of the P-C stretching frequency in the vibration
spectrum with that of methyltriphenylphosphonium ion
(P-CH3 single bond).
Received: July 22nd, 1965
[Z 36/862 IEI
German version: Angew. Chem. 77, 863 (1965)
Table 1. P-C stretching frequencies [cm-11 for compounds (3)-(6).
[ I ] B. Hererich and E. Himmen, Ber. dtsch. chern. Ges. 61, 1825
[2] Here 3H implies a mixture of tritium with ordinary hydrogen.
[3] A sample of methyl a-D-idoside was kindly supplied by Prof.
T. Reichsfein, and a sample of D-idosan triacetate by Dr. N . K.
[4] H. Simon, Z . Naturforsch. 18b, 360 (1963); H. Simon and
J. Sfefens, Chem. Ber. 95, 358 (1962).
Synthesis and Properties of Tantalum Oxide
Nitride, TaON
We have studied the infrared spectra of methyltriphenylphosphonium iodide (3), methylenetriphenylphosphorane
(4), phenacyltriphenylphosphonium bromide (5) and
phenacylidenetriphenylphosphorane. In order to recognize
the P-C stretching frequency among the multiplicity of
bands [(4) has 37 atoms and thus 105 normal vibrations],
we labeled the compounds (3)-(6) in the methylene group
with 13C or D. Thereby the frequencies of those vibrations in
which the labeled atoms partake are shifted whereas the
frequencies of all the other vibrations of the molecule remain
almost unchanged [I]. The labeled compounds were crystallized and were examined spectroscopically as suspensions
in Nujol with careful exclusion of air and moisture. Table 1
shows the results. These indicate that the PC bond orders
(3) Ph3P@CH@
( 4 ) Ph3PCH2
(5) Ph3P@-CHz-CO-PbBr@
(6) Ph3PCH-CO-Ph
of the methylenephosphoranes (4) and (6) are only slightly
higher than those of the corresponding quaternary salts
(3) and (5).
Among P-0 and P-N compounds, substantially larger
differences are found between compounds with single and
double bonds than among the P-C compounds (Table 2).
By Prof. Dr. G. Brauer and Dr. J. R. Weidlein
Chemisches Laboratorium
der Universitat Freiburg (Germany)
During the preparation of red tantalum nitride Ta3Ns [ l]
from Ta205 and NH3, intermediates of various colors are
encountered. We have now found that the changes in color
are due to the transient formation of tantalum oxide nitride
TaON. This compound is also formed in high purity by
heating Ta2O5 or Ta3Ns in a current of ammonia containing
a little moisture at about 800 ‘C.
Tantalum oxide nitride TaON is a yellow-green solid with
d = 10 g/cm3. Its monoclinic crystal structure is probably of
the Baddeleyite (zirconium dioxide) type [2]; its lattice parameters are a = 4.966, b = 5.034, c = 5.185 A, andp = 99.65 O .
Received: July 28th, I965
[Z 421868 IEI
German version: Angew. Chem. 77, 913 (1965)
[ l ] G. Brauer and J. R. Weidlein, Angew. Chem. 77, 218 (1965);
Angew. Chem. internat. Edit. 4, 241 (1965).
[2] D. K. Smith and H. W . Newkirk, Acta crystallogr. 18, 983
I X=O[2]
I X=NHf3]
I 1350-1200
I X=OH[41
1 X=NHz[51
The remarkably small differences in frequency of the P-C
vibrations of methylenephosphoranes and the corresponding
quaternary salts show that the bond between phosphorus
and methylene-carbon in methylenephosphoranes has only
slight double-bond character. With the equation for a
diatomic harmonic oscillator, the following force constants
were calculated from the P-C frequencies: (31, 3.6 mdyne/A;
(4), 4.9 mdyne/A. From H. Siebert’s rules [6] a rough
estimate leads to 1.3 for the bond order in (4).Thus, if one
assumes resonance between the ylene form ( I ) and the ylide
form (2) of methylenephosphoranes, then according to the
spectroscopic findings the latter form preponderates.
Received: August 2nd, 1965
[Z 431867 IEI
German version: Angew. Chem. 77, 867 (1965)
Infrared Spectroscopic Investigations on
By Prof. Dr. W. Liittke and Dipl.-Chem. K. Wilhelm
Organisch-Chemisches Institut
der Universitat Gottingen (Germany)
For an understanding of the Wittig reaction it is important
to know the type of bonding present in methylenetriphenylphosphoranes, and in particular whether the substances are
better described by the ylene formula ( I ) or by the ylide
Angew. Chem. internat. Edit.
Vol. 4(I965) / No. 10
111 R. Kiibler, W. Liiftke, and S. Weckherlin, Z . Elektrochem. 64,
650 (1960); S. Weckherlin and W. Liiffke,ibid. 64, 1228 (1960);
R. Kiibler and W. Liiftke, Ber. Bunsenges. physik. Chem. 67, 2
(1963); S. Weckherlin and W . Liiftke, Tetrahedron Letters I964,
171 1 ; G. Schroeder, DiplomaThesis, Universitat Gottingen 1964.
[Z] M . Halman and S . Pinchas, J. chern. SOC.(London) 1958,3264[3] W. Wiegrube, Dissertation, Universitat Miinchen, 1964.
141 L . C.Thomas and R . A . Chittenden, Spectrochim. Acta 20,
467 (1964).
[5] H. Sisler and N. L . Smith, J. org. Chemistry 26, 611 (1961).
161 H . Siebert, Z . anorg. allg. Chem. 273, 170 (1953).
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investigation, spectroscopy, methylenetriphenylphosphoranes, infrared
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