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Methyleneaziridine-Cyclopropanimine Valence Isomerization.

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containing B-H or P-H. B2H6 is slowly evolved from
the ethereal solution of the boron hydride product (1)
above 0°C; evolution of B2H6 is complete (0.32 mmol,
87%) after 100h at room temperature. Neither PH, nor H,
was found to be formed during this decomposition.
(3a) decomposes slowly above 120°C and rapidly at
19OoC,( 5 a ) and (6a) being formed quantitatively. These
products can, however, arise only by cheletropic decomposition of the cyclopropanimine intermediate ( 4 a ) ; and
this is indicated especially by the fact that the cyclopropanimine ( 4 b ) also thermolyzes quantitatively in this manner
above 140°C[2.61.If the thermolysis of ( 3 a ) is followed
by NMR spectroscopy, transient signals appear that belong
to the isomer (3'a) (3.84, 4.06 ppm, >C=CH2) and,
very probably, to the cyclopropanimine ( 4 a ) (at 1.1
1.3ppm).
Received. February 2, 1973 [Z 802 IE]
German version: Angew. Chem. 85,410 (1973)
[I] H . 1. Schlesinger. D. M. Rirrer, and A. B. Burg, J . Amer. Chem.
SOC.60, I296 (1938).
[2] A . B. Burg and H . Heinen, Inorg. Chem. 7, 1021 (1968); 1. B. Mtsha
and A. B. Burg, ibid. 11, 664 (1972).
[3] C . R. Earon and W. N . Lipscomb: NMR Studies of Boron Hydrides
and Related Compounds. W. A. Benjamin, Reading, Ma. 1969.
[4] H . 1. Schlesinger, D . M. Rirrer, and A. B. Burg, J. Amer. Chem.
SOC.60, 2297 ( 1938).
[5] E. M a w and A. W Luubenguyer, Monatsh. Chem. 101, 1138 (1970).
[6] We thank Dr. M. N.S. Hi[l, University of Newcastle-upon-Fyne, for
measuring the "B-NMR spectrum.
Methyleneaziridine-C yclopropanimine
Valence Isomerization ['*I
R'
By Helmut Quast and Wolfgang Ris/er[*]
As part of our study of the thermal reorganization of
nitrogen analogs of methylenecyclopropane", we report
here the synthesis of a methyleneaziridine substituted at
the double bond and also the first proof of the methyleneaziridine-cyclopropaniminevalence isomerization that has
been repeatedly postulated[31.
Methyleneaziridines unsubstituted on carbon have been
known for a long time, but more highly substituted representatives of this class of compounds have not yet been
de~cribed'~].
By reaction of the bromoallylamine (2) [readily accessible by prolonged heating of ( I ) with tert-butylamine at 150°C[5'; yield 67-69%, b. p. 89-89.S°C/15 torr]
with NaNH, in liquid NH, we obtained 1-tert-butyl-2-isopropylideneaziridine (3a) (yield 50--60%;
b. p.
R3
RZ
Whereas in the case of ( 3 a ) there is in principle a threecomponent system [(3a), (Ya), ( 4 a ) ] , the kinetics of
the thermolysis of the C-unsubstituted methyleneaziridines
(3c)-(3e)
are expected to be simpler since there the
possible transformation (3) + (3') degenerates to a valence
topomerization. We therefore studied the thermolysis of
(3c)-(3 e) by NMR spectro~copy['~.The intensities of
the olefinic proton signals of (3c)-(3e)
decreased in
Table 1. Rate constants k, and activation parameters (for 150°C) of the isomerization ( 3 ) - ( 4 )
105
f3c)
f3d)
(3ei
150.0"C
170.0 'C
3.50 20.03
1.561 +0.008
21.4
0.085&0.002
IS- '1
20.1
0.510~0.006
48 T / 1 4 torr), whose structure follows from elemental analysis and spectroscopic results. IR (CCI,): 3025 (CH,),
1792cm- (=
' )'.
NMR ("I4,
90 MHz):
(9H/s)1
124 (M-CH3,
1.70-1.77 PPm(8H/m). MS: 139 (',40%),
ll%), 83 (M-CIHS, 55Yo), 82 (M-C,Hg, 100%).
[*] Doz. Dr. H. Quast and Dip].-Chem. W. Rider
Institut fur Organische Chemie der Universitat
87 Wurzburg, Landwehr (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft.
The results are taken from the Diploma Thesis of W Rider, Universitat
Wbrzburg 1973.
414
k,
190.0 "C
AH*
[kcal mol-
127.5 fO.8
34.1 fO.8
3.29 f0.04
34.8 ~ 0 . 2
'1
AS'
[cal mol- I deg-
'1
1.0+1.7
-4.8f0.5
a first-order reaction during several half-lives, with
[(3)] = [(3)],exp[ - klt] (Table 1).
The cyclopropanimines ( 4 c)--(4 e) were always the primary products, undergoing slow conversion into ethylene
and the isocyanides (6c)-(6e) (maximal yield 20-25%)
and, as thermolysis proceeded, further into unidentified
products[s1. For example, from (3c) we obtained after
5.5min at 190°C (half-life 9min) a mixture containing
71% of (3c), 28% of (4c), 1% of ethylene, and 1%
of (6 c) which remained unchanged at room temperature.
The structure of the cyclopropanimine (4c) is proved
by the AABBX, spectrum (AA'BB part at 1.2ppm, X3
part at 3.24 ppm) and decoupling experiments.These results
show that the experimentally determined rate constants
are to be assigned to the isomerization ( 3 ) - + ( 4 ) and
that here k , $k2[9], as also for (4b)f2-6!
Considering the notorious instability of cyclopropanones["], it is surprising how stable the corresponding
Angew.
Chum. infernat. Edit. Vol. 12 ( 1 9 7 3 ) 1 No. 5
imines ( 4 c ) - ( 4 e )
accessible.
are and that they are now readily
Received: February 12, 1973 [Z 803 IE]
German version: Angew. Chem. 85,411 (1973)
[ I ] H . Quast and E . Srhmitf, Chem. Ber. 103, 1234 (1970); Angew. Chem.
82, 395 (1970); Angew. Chem. internat. Edit. 9 , 381 (1970).
[2] H . Quasr, E . Schmitt, and R . Frank. Angew. Chem. 83, 728 (1971);
Angew. Chem. internat. Edit. 10, 651 (1971).
[3] J . A . Dryrup and R . B. Grrenwaid, Tetrahedron Lett. 1966, 5091;
J . C. Sheehan and M . M . Nafissi-V, J. Amer. Chem. SOC. 91, 4596
(1969); cf., however, E. R . Tafary, A . E. Dupuy, j r . , C . K . Johnson, 7:
P. Pirottr, W A . Fietcher, and R . E . Thompson, Tetrahedron Lett. 1970,
4435, and [2].
[4] 0.C . Drrmrr and G . E . H a m : Ethylenimine and Other Aziridines.
Academic Press, New York 1969; J . E. Den Besten and R . C. Wengrr,
J. Amer. Chem. SOC.87, 5500 (1965). however, obtained, from carbon
vapor and imines, mixtures of products including components that were
regarded as more highly substituted methyleneaziridines on the basis
of their IR and mass spectra.
[5] Following S. R . Sandier, J . Org. Chem. 33,4537 (1968).
[6] The isomers ( 3 6 ) and (3'b) were not detected, so in this case
k , > 100 k 2 andlor k3sk, [2].
[7] 0.16-0.18 mol of benzene per mol of (3) served a s internal intensity
standard.
[8] In the case of ( 3 r ) , (50) appeared towards the end ofthe thermolysis
and, as consecutive product from ( 6 e ) , pivalonitrile.
191 Neither a steady-state approximation nor an equilibrium approximation describes the findings; cf. C . W Pyun, J. Chem. Educ. 48, I94
(1971).
[lo] N . J . Turro, Accounts Chem. Res. 2. 25 (1969).
A Bicyclic Phosphorus Trisulfur Pentanitride
By Herbert W Roesky and Olaf PetersenC']
We have isolated a phosphorus-containing sulfur nitride
of the composition S3NSPF2(complete elemental analysis)
and the unusual structure (1) from the products of reaction
of phosphorus pentafluoride with N,N'-bis(trimethylsily1)sulfur diimide"]. Since the sulfur diimide is in excess at
the beginning of the reaction we assume that
F,P[N=S=N-Si(CH3)3]3
is first formed and then reacts
further with PF, to yield ( I ) , (CH3),SiF, and (NPF,),
in the ratios 1 :3: l/n. It is known that similar reactions
of PF, d o not lead to (NPF,), rings but that derivatives
of PF; are formed.
for I9F-NMR, and 85% H 3 P 0 4 as external4andard for
31P-NMR).This accords with the proposed structure ( I ) ,
in which one fluorine atom is in an axial and another
in an equatorial position. The nitrogen atoms assume differing positions for steric reasons. S2N3PF2 is found as the
ion with the highest mass number (m/e= 175, 8%) in the
mass spectrum; this fragment arises by loss of NSN from
( 1 ) and can be regarded as a six-membered ring system;
elimination of SN is known to occur in mass-spectrometric
investigation of sulfur-nitrogen rings[31.Other characteristic fragments are: rn/ci= 161 S2N2PF, (48.4%), 129
NSNPF, (5.1%), 115 SNPF2 (23.7%), 92 S2N2 (4%), 78
SNS (9.6%), 69 PF2 (38.5%), 64 NPF (3.5%), 50 PF (3.7%),
46 SN (loo%),45 N P (1.3%), 32 S (21.8%), 28 N, (6.2%).
Absorptions (cm-I) were observed in the IR spectrum
at 1185 vs, 1138 vs, 1020 w, 1002 m, 960 s, 935 s, 835
s, 728 s, 707 s, and 662 s.
Experimental.
A slow stream of PF, is introduced, with stirring, into
[(CH3)3SiN]2S (5g, 0.025mol) contained at 0°C in a twonecked flask (250 m1)fitted with a gas inlet tube (not dipping
into the liquid) and a final condensation trap (acetonepry
Ice). When reaction is complete (ca. 4 h), unchanged PF,
can be observed at the exit from the trap, and the flask
containing the reaction mixture is then slowly warmed
to room temperature. (CH3)&F collects in the trap, and
the product ( I ) (yield I-.%)
sublimes from the dark
brown residue at room temperature under oil-pump
vacuum.
Received. December 7, 1972,
revised: February 22, 1973 [Z 805 IE]
German version' Angew Chem. 85,413 (1973)
[I] U . Wannagar and H. Kuckertz, Angew. Chem. 74, I17 (1962); Angew.
Chem. internat. Edit. I , 113 (1962); 0. J . Scherer and R . Wirs. Z. Naturforsch. 25 b, 1486 (1970).
[2] R . Schmutzler, Angew. Chem. 77, 530 (1965): Angew. Chem. internat.
Edit. 4, 496 (1965).
[3] H . W ROC+]> and 0.P e t r r s m , Angew. Chem. 84,946 (1972). Angew.
Chem. internat. Edit. 1 1 , 918 (1972).
A New, Unusually Stable Type of
Organo-copper and -silver Compounds
By Hubert Schmidbaur, Jiirgen Adlkofer, and
Wolfgang Buchner '1
( I ) is a crystalline, golden-yellow solid, extremely sensitive
to moisture and sublimable at room temperature in an
oil-pump vacuum. The most probable configuration for
the pentacoordinated phosphorus is assumed to be a trigonal bipyramid. From 31P- and I9F-NMR studies the
fluorineatoms are not exclusively axial (a) and the nitrogen
atoms exclusively equatorial (e), as is usualf']; instead,
one finds two doublets in the 31P- and also two doublets
in the 19F-NMR spectrum: &= + I1.5ppm; J(PF')= 1008,
J(PFa)=925, J(FaFe)=
86 Hz; 6Fa=85.4, 6,.=46.8 ppm
(measured at 35 "C; CFCl, as solvent and internal standard
[*] Prof. Dr. H. W. Roesky and Dipl.-Chem. 0. Petersen
Anorganisch-chemisches Institut I der Universitat
6 Frankfurt I , Robert-Mayer-Strasse 7-9 (Germany)
Angew. Chem. infernat. Edir. J Vol. 12 ( 1 9 7 3 ) j N o . 5
Replacing simple alkyl groups by trimethylsilylmethyl
groups sometimes effects considerable stabilization of
organometallic compounds[" '1. We have now found that
this effect of the (CH,),Si-CH,
group is greatly exceeded
by that of the i s o e l e ~ t r o n i c [ ~phosphonium
~
group
(CH3)3P+-CH2, and that even extremely weak bonds
such as the Cu-C and the Ag-C unitl41 become capable
of existence under normal conditions when this ligand is
used.
Treating anhydrous copper(1) chloride with salt-free trimethylmethylenephosph~rane[~~
(molar ratio 1 :2) in benzene or toluene under an inert gas at room temperature
leads, in a homogeneous reaction, to tetramethylphosphonium chloride and a metalated ylide of composition
and structure (1).
[*] Prof. Dr. H. Schmidbaur, DipLChem. J . Adlkofer, and
Dr. W. Buchner
Institut fur Anorganische Chemie der Universitat
87 Wiirzburg, Landwehr (Germany)
415
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valence, methyleneaziridine, isomerization, cyclopropanimine
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