[NORG. NUCL. CHEM. LETTERS
Vol.]4, pp. 511-513,
1978. Pergamon Press. Printed in Great BritaJ
THE IDENTIFICATION OF SOME NEW AZIDO-DERIVATIVES
OF PHOSPHORUS
K.B. Dillon, A.W.G. Platt and T.C. Waddington Chemistry Department,
University of Durham, Durham
South Road,
DHI 3LE
(7~eceived 2] September 1978; received for publication 12 October 1978) Although several derivatives of phosphorus(III), thiophosphoryl
phosphoryl and
halides with one or more of the halogens replaced by pseudo-
halides such as SCN, OCN or (for P(III)) CN are known, and their 31p n.m.r. shifts reported (1,2), comparatively azido-analogues
(3,4).
little work has been carried out on
The only compounds reported without an organo-group
attached to phosphorus are the fully-substituted
molecules P(N3) 3 (5) and
PO(N3) 3 (4,5), the cation P(N3)4+ (6,7), and the anions P(N3) 6- (8,9), PO2(N3) 2- (IO), PSO(N3) 2- (11), PS2(N3) 2
(Ii) and PSON3F- (Ii).
some of these were prepared at or below room temperature starting materials, mixed azido-halogeno-intermediates The high temperature
(438-44OK)
from halogenated
were not observed.
reaction of excess PBr 3 with sodium azide
gave a mixture of (Br2PN) n polymers (12), and no intermediate detected.
Even though
species were
Similarly the photolytic reaction of HN 3 with PC13 between 195
and 206K was reported to yield a tetrameric product of composition with no direct evidence
(P5N8CI9)4 ,
for PCI2N 3 although this was postulated as taking part
in the reaction (13). We have prepared the new azido-compounds POBrn(N3)3_n,
where X = C1 or Br and O ~ n ~
to an acetonitrile
PXn(N3)3_n,
PSXn(N3)3_n,
3, by addition of sodium azide
solution of the appropriate phosphorus(III)
or (V) halide.
The new species may be readily identified by 31p n.m.r, spectroscopy by Table I. Solution i.r. spectra also confirmed
and
as shown
the presence of coordinated azide groups.
While the chemical shift for PO(N3) 3 is in good agreement with literature data (4,5,14),
the value for P(N3) 3 differs considerably
511
from that of 16 p.p.m.
512
Some New Azido-Derivatives of Phosphorus
TABLE i
31p n.m.r, data for some Azido-derivatives of Phosphorus in MeCN solution
6 31p (p.p.m.)* for:X
PX 3
PX2 (N3)
PX(N3 )2
P (N3)3
Br
-230.1
-170. O
-157. I
-134.6
CI
-220.6
- 164.4
-149.1
-134.6
FSX 3
PSX2(N 3 )
PSX(N3) 2
PS(N3) 3
Br
108.0
19.4
-35.5
-62.9
CI
-34.0
-51.0
-61.1
-63.0
POX 3
POX2(N 3 )
POX(N3) 2
PO(N3) 3
Br
101.6
44.4
12.2
-0.5
Relative to external 85% H3P04, with the upfield direction taken as positive.
given previously (5).
This resonance is almost certainly due to the main
decomposition product of PN9, as mentioned below. Addition of excess azide ion causes complete displacement of the halogen to give the fully-substituted species.
Phosphorus triazide decomposes
smoothly in solution at or just above room temperature with the liberation of nitrogen (at a pressure sufficient to blow out the stoppers from n.m.r. sample tubes), accompanied by the appearance of a strong 31p resonance at 16.2 and a weaker one at 6.2 p.p.m., very similar to the spectrum reported for the PsN8CI9 tetramer (13).
Our product contains no chlorine, however,
since it may be obtained from either PBr 3 or PCI 3 as starting material, and the solution i.r. spectrum still shows the bands characteristic of coordinated azido-groups.
Solutions of PS(N3)3, on the other hand, remained
Some New Azido-Derlvatives of Phosphorus
stable at room temperature for several days at least.
513
Further investigations
on related reactions and on the nature of the decomposition products are continuing.
Acknowledgement We thank the Science Research Council for the award of a maintenance grant (to A.W.G.P.).
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2.
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