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Detection of Aryl(vinyl)nitroxides by ESR Spectroscopy.

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It is thus proved that oxophosphoranesulfenyl chlorides
\
P(0)SCI
<P-0-R(H)
and
esters
of
tervalent
phosphorus
acids
give first the thiol form (3) of the monothiopyrophosphate system [31.
The second step in the reaction is blocked if the starting
material is a nitrile with a secondary $-carbon atom, as ( I ) ,
R = C6Hs or CH3; but even then the reaction proceeds
beyond the nitrone stage ( 3 ) , giving the aryl(viny1)nitroxides
(5), which can be detected by their ESR spectra.
Synthesis of bis(5,5-dimethyt-2-oxo-l,3,2Pv-dioxaphosphorinanyI)sulfide ( I ) :
1
1
I I
H
A solution of sulfur dichloride (2.06 g, 0.02 mole) in benzene
(20 ml) was added dropwise to a solution of 5,5-dimethyl-2oxo-1,3,2-dioxaphosphorinane (3) (6.0 g, 0.04 mole) and
triethylamine (4.04 g, 0.04 mole) in benzene (50 ml) at 20 to
30°C (ice cooling). The whole was stirred at room temperature for 1 h and the crystal mass was filtered off with suction, washed with benzene (2 x 50 ml) and water (2 x 50 ml),
and dried. Yield, 4,O g; m.p. 162-167 "C; m.p. 185-188 "C
after recrystallization from benzene/chloroform.
Received: September 19th, 1967
[ Z 627 IE]
German version: Angew. Chem. 79, 1069 (1967).
[*] Prof. J. Michalski, Dr. M. Mikolajczyk, B. Mkotkowska,
and Dr. A. Zwierzak
Institute of Organic Synthesis,
The Technical University (Politechnika),
and the Institute of Organic Chemistry of the Polish
Academy of Sciences
Lodz 40 (Poland)
[l] R. S . Edmundson, Chem. and Ind. 1963, 784.
[**I Note: The compound ( I ) is not produced in the reaction of
bis(5,5-dimethyl-2-oxo-1,3,2-P~-dioxaphosphorinanyl~ disulfide
with triphenylphosphine IR. S. Edmundson, J. chem. SOC.(London) B 1967, 16351.
[2] J. Michalski and B. Phzka-Krawiecka, Chem. and Ind. 1296,
1052.
[3] J . Michalski, M . Mikolajczyk, and A . Rarajczak, Chem. and
Ind. 1962,819;J. Michatski, M . Mikolajczyk, and A . Skowronska,
Chem. and Ind. 1962, 1053.
Fig. 1 .
Detection of Aryl(viny1)nitroxides by ESR
Spectroscopy
If 2,3-diphenyIpropionitrile ( I ) , R = H, is treated with an
aromatic nitroso compound (2) in methanol containing
sodium methoxide, the expected nitrone ( 3 ) , R = H, is not
obtained because it reacts at once with further nitroso compound, giving the a,a',N,N'-tetraphenyldinitrone [benzoin
bis(pheny1imide N-oxide)] (4) by dehydrogenation [I].
H 5 7 6 pH5
A
iA r - N O
-HCN-
R = C6H5,CH,
I R IAr
1
Coupling constants (gauss)
aN
aH (o,p-Ar)l OH (m-Ar)
2.37
2.37
2.33
2.62
2.64
1080
(Sc), and (5e).
A solution of a nitrile ( I ) (1 mmole) and a nitroso compound
(2) (1 to 2 mmoles) in t-butyl alcohol (20 ml) is added to a
solution of potassium t-butoxide (5 mmoles) in t-butyl
alcohol (20ml) under nitrogen. The dark red mixture is
stirred for 45 min at room temperature. Glacial acetic acid is
added to give a weakly acid reaction, the solvent is distilled
off in a rotary evaporator, and the solid residue is taken up
in benzene (50 ml) and water (50 ml). The benzene phase is
separated, washed several times with water, and dried. For
determination of the ESR spectra samples of the benzene
solutions were further diluted.
In accord with the coupling of the unpaired electron with the
nitrogen atom, the ESR spectra of these nitroxides consist of
three line groups of about the same intensity [21. Quadruplet
splitting of the individual line groups (approximate intensity
ratio 1 :3 :3 : 1) in the spectrum of (5c) is caused by the three
equivalent 0- and p-protons of the phenyl nucleus on the
nitroxide group. In the spectrum of (5a) each of these lines is
additionally split three-fold by the m-protons of this phenyl
nucleus.
The density of the unpaired electron in the vinyl group and
the three neighboring phenyl nuclei is apparently too small
for visible splitting by these phenyl protons to arise. O n the
By H . G . Aurich and F. Baer[*l
H-C-7-H
CN
ESR spectra of the aryl(viny1)nitroxides (5a),
0.82
0.82
-
0.95
-
I aH ('333)
0.6
0.62
Angew. Chem. internat. Edit.
/ Vol. 6 (1967) No. 12
other hand, coupling with the protons of the methyl group in
(5d) and (Se) increases the number of lines. Although the
spectrum of (5d) is thus rendered very complex, the quadruplet splitting by the methyl protons can be readily recognized
on comparison of the spectra of (5.) and (Sc).
Received: September 20th, 1967
[ Z 628 IE]
German version: Angew. Chem. 79, 1070 (1967)
[*] Doz. Dr. H. G. Aurich and Dr. F. Baer
Institut fur Organische Chemie der Universitat
Bahnhofstr. 7
355 Marburg (Germany)
[ l ] H. G. Aurich, Chem. Ber. 98, 3917 (1965).
[2] For the nitroxides studied here, the intensity of the outside
group of lines at the high field side is somewhat decreased. This
phenomenon has often been observed in the ESR spectra of
nitroxides: K . Umemoto, Y . Deguchi, and H . Takaki, Bull. chem.
SOC.Japan 36, 560 (1963).
In benzene, filtration, and removal of the solvent. After
renewed drying in a vacuum 139 mg [32% calc. o n Cr(CO),]
of the reddish-violet complex was isolated.
2. p-Cyanogenbis(pentacarbonylmo1ybdenum): Preparation
as for 1, but benzene was used as solvent for the irradiation.
Yield : 115 mg (22 %).
3. p-Cyanogenbis(pentacarbony1tungsten): Preparation as
for 1. Yield: 252 mg (36 yo).
Received: September 25th, 1967
[ Z 629 IE]
German version: Angew. Chem. 79, 1071 (1967)
[*] Dr. J. F. Guttenberger
Institut fur Physikalische Chemie der Universitat
Marcusstr. 9/11
87 Wurzburg (Germany)
[I] H . T. Knight and J. P. Rink, J. chem. Physics 35, 199 (1961).
[2] L. BurneNe, Theoret. chim. Acta 2, 177 (1964).
[3] W. Strohmeier and K . Cerlach, Chem. Ber. 94, 398 (1961).
[41 G. Brnuer: Handbuch der Praparativen Anorganischen Chemie. Enke-Verlag, Stuttgart 1954, p. 502.
pCyanogenbis(pentacarbonylmeta1)Complexes
By J . F. Guttenberger [*I
Cyanogen reacts photochemically with hexacarbonylmetals
with formation of intensely colored compounds of composition [(OC)sMNC] ( I ) , that are not attacked by oxygen.
Determination of the molecular weights of these products
gives values that correspond t o twice the molecular weights
of ( I ) . It is therefore assumed that the C-C bond in (CN)z
remains intact and that this substance links two pentacarbonylmetal fragments as a bifunctional donor, so that pcyanogenbis(pentacarbonylmeta1) complexes
(0C)sMNC -CNM(C0)5
(2)
are formed. This behavior is in agreement with the high
dissociation energy (145 kcal/moleIll) of the C-C bond in
cyanogen and is supported by calculations of electron density
distribution
according t o which the external bonds in
(CN)z are barely changed by conjugation. Further, the
spectroscopic data given in the Table accord with structure
(2).
Preparation of the Complexes:
An apparatus described by Strohmeier[31 was used for irradiation of the substances. Cyanogen was prepared and purified
as described in [41. It was carried into the irradiation cuvette
in a slow N2 stream that passed through the (CN)2 production apparatus and the cuvette during the irradiation.
1. p-Cyanogenbis(pentacarbony1chromium): 2 mmoles (440
mg) of Cr(C0)6 in 25 ml of tetrahydrofuran was irradiated
for 2 11 under a stream of Nz and (CN)2. Then the solvent was
removed in a rotary evaporator at 40°C/40mm, and the
residue was dried in a vacuum at 40°C/10-2mm. The compound was freed from decomposition products by dissolution
Preparation and Properties of Diammonium
Dioxodiselenomolybdate(vr)
By A . Miiller, B. Krehs, and E. Diemannr*J
If hydrogen selenide is led into a saturatedsolution of molybdenum trioxide in 2 5 % aqueous ammonia until a deep red
color appears, and the solution is then saturated with oxygenfree carbon dioxide with strong cooling (ice-salt mixture),
olive-green crystals of the compound (NH&Mo02Se2 (Z)
separate after a short time. The MoO2Se:- ion has not been
previously observed either in solution or in the crystalline
state. Substance ( I ) was identified by elemental analysis and
by its IR and UV spectra.
Compound ( I ) dissolves in water with an intense orange-red
color and is almost insoluble in ether or alcohol. Like the
corresponding tetraseleno salt it is extraordinarily sensitive
t o oxygen, and all operations with it must therefore be carried
out in a closed system with an atmosphere o f a protecting gas.
The IR spectrum of the solid between 4000 and 250cm-1
shows the internal vibrations of the NH4'ion at ca. 3200 cm-1
[v3(F2)] and 1395 cm-1 [ v 4 ( F 2 ) ] . The absorption frequencies
o f t h e dioxodiselenomolybdate(v1) ion can be assigned appoximately on the basis of point group C2": 8 3 0 cm-1: vS(MoO)h
vl(A1); 790 cm-1: va,(MoO) rfi vg(B1); also 362, 344, and
285 cm-1: vs(MoSe) * v2(A1), vas(MoSe) A vg(Bz), and
S(Mo02) ~3(A1).? The assignment vs(MoO) > vas(MoO)
can be regarded as certain since the bands of higher vibration
in the I R spectrum occur with lower intensity and since only
this assignment leads t o a reasonable value for the lengthlength interaction force constant. Not much can be said
about the series VZ(AI), v3(Al). and vg(B2); exact assignment
is not possible without a knowledge of the Raman spectrum.
IR [a] vCN(cm-1)
vcO(cm-9
Mol. wt. [b]
2263 vw, 21 18 vw
2067 w, 2038 m, 1980 s, 1959 m
2261 vw
2075 w, 2043 m, 1985 s, 1960 m
2267 vw. 2107 vw
2069 w, 2027 m, 1975 s, 1955 m
425 (436)
cu. 600 (524)
cu. 900 (700)
Color
Reddish-violet
Dark brown
Violet
Stability
Solubility
M.p.
tal In CCII; accuracy j r3 cm-1; vw
=
very weak; w
=
weak; m
=
medium; s = strong.
[bl Osmometric i n benzene. The low solubility of the molybdenum and tungsten compounds prevented accurate measurement.
The theoretical values are given in parantheses.
Angew. Chem. internat. Edit.
1 Vol. 6 (1967) / No. 12
108 1
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