The reaction of N-dichlorophosphoryl-P-trichlorophosphazene with alkyl grignard reagents

Article abstract of DOI:10.1002/hc.10153

The reactions of N-dichlorophosphoryl-P-trichlorophosphazene Cl₃P=N-P(O)Cl₂ (1) with benzylmagnesium bromide, 2-phenylethylmagnesium bromide, trimethylsilylmethylmagnesium chloride, n-butylmagnesium bromide, cyclohexylmagnesium bromide, cyclopentylmagnesium bromide, tert-butylmagnesium bromide, iso-propylmagnesium bromide, and ethylmagnesium bromide were studied. Tri- and pentaalkyl phosphazenes were obtained in very poor yield from trimethylsilylmethylmagnesium chloride and cyclohexylmagnesium bromide, respectively. Trialkylphosphoryl compounds formed from benzyl-, 2-phenylethyl-, and n-butylmagnesium bromide. No phosphorus compound could be isolated from the reaction of 1 with t-butyl-, cyclopentyl-, iso-propyl-, and ethylmagnesium bromide.

Full text of DOI:10.1002/hc.10153

Heteroatom Chemistry
Volume 14, Number 5, 2003
T
he Reaction of N-Dichlorophosphoryl-
P-trichlorophosphazene
with Alkyl Grignard Reagents
1
1
2
F. Aslan, A. I. Ozturk, and M. Arslan
1
Chemistry Department, Harran University, TR-63100 Sanliurfa, Turkey
2
Chemistry Department, Firat University, TR-23169 Elazig, Turkey
Received 31 October 2002; revised 16 December 2002
been reviewed [6,7]. The structures of 1 [8] and
of pentaamino [9,10] and pentaalkoxy derivatives
ABSTRACT: The reactions of N-dichlorophosphoryl-
P-trichlorophosphazene Cl
3
P N P(O)Cl
2
(1) with
[11–15] have been obtained. The partial aminoly-
benzylmagnesium bromide, 2-phenylethylmagnesium
bromide, trimethylsilylmethylmagnesium chloride, n-
butylmagnesium bromide, cyclohexylmagnesium bro-
mide, cyclopentylmagnesium bromide, tert-butylmag-
nesium bromide, iso-propylmagnesium bromide, and
ethylmagnesium bromide were studied. Tri- and pen-
taalkyl phosphazenes were obtained in very poor
yield from trimethylsilylmethylmagnesium chloride
and cyclohexylmagnesium bromide, respectively. Tri-
alkylphosphoryl compounds formed from benzyl-, 2-
phenylethyl-, and n-butylmagnesium bromide. No
phosphorus compound could be isolated from the re-
action of 1 with t-butyl-, cyclopentyl-, iso-propyl-, and
ethylmagnesium bromide. ꢀC 2003 Wiley Periodicals,
sis and alcoholysis of 1 with methylamine and tert-
butylamine [16], diisopyropylamine [17], o-dichloro
and o-dimethylphenol [18], 2,4,6-tert-butylphenol
and 2,6-di-tert-butyl-4-methylphenol [19], and allyl
alcohol [20] have been reported. These molecules
can be used as structural models for phosphazene
polymers with a large range of properties [2,21] and
applications [22–29].
The reactions between halogenophosphazenes
and main-group organometallic reagents can be
complex [2,30,31]. Several transition-metal-con-
taining cyclic phosphazenes have been synthesized
[32]. In the synthesis of alkyl- and aryl-substituted
phosphazenes, halophosphazenes are reacted with
organolithium or Grignard reagents [33–39]. Al-
though there are many publications about cyclic
or polymeric alkyl- or arylphosphazenes [39–46],
the synthesis of alkyl-substituted phosphazenes has
been performed with only limited success [47–49].
Here we report the reactions of 1 with alkyl Grignard
reagents.
Inc. Heteroatom Chem 14:413–416, 2003; Published on-
line in Wiley InterScience (www.interscience.wiley.com).
DOI 10.1002/hc.10153
INTRODUCTION
Since short open-chain phosphazenes are sensi-
tive to air and moisture, only a few of them have
been characterized in detail [1–5]. The reactions of
RESULTS AND DISCUSSIONS
Cl
3
P N P(O)Cl (1) with amines and alcohols have
2
Tri- and pentasubstituted monophosphazenes 4 and
6
were obtained in 4 and 1% yield from the reac-
Correspondence to: M. Arslan; e-mail: marslan07@yahoo.com.
tion of 1 with trimethylsilylmethylmagnesium chlo-
ride (b), and cyclohexylmagnesium bromide (c), re-
spectively. Phosphoryl compounds 2, 3, and 5 were
Contract grant sponsor: Firat University Research Fund.
¨
Contract grant number: FUNAF-350.
ꢀ
c 2003 Wiley Periodicals, Inc.
4
13

4
14 Aslan, Ozturk, and Arslan
TABLE 2 Characteristic IR Vibrations of 1–6 (cm 1)
−
detected from the reaction of 1 with benzyl-, 2-
phenyl-ethyl-, and n-butylmagnesium bromide (a),
respectively.
νC H ar.
νC H al.
νP
N
νP
O
νP
N
νP Cl
1
2
3
4
5
6
–
3050
3050
–
–
–
–
1338 1263
770
–
–
761
–
750
650
–
–
536
–
–
Cl
3
P N P(O)Cl + 5 RMgX
2
2900
2900
–
–
1187
1153
1
2900–2800 1319 1251
2950–2850 1160
2930–2852 1220 1170
−
→ (a) R[
3
P O
R: PhCH
–
2
(2), PhCH
2
CH
2
(3), n-C
4
H
9
(5)]
(
b) R
3
P N P(O)Cl2
[
R: Me SiCH (4)]
3
2
are generally observed at the lowest field and they
show the largest JPC values. In compound 6, the POR
and PNR environments can be distinguished, espe-
cially, C in PNR are shielded more than in POR
(Table 5).
The electron impact MS spectra of 2 showed the
well-defined molecular ion at m/z 320 (25%). The
molecular ion peak of 3 was not observed, but the
peaks at m/z values of 91 and 105 correspond to the
(
c) R P N P(O)R2
3
[
R: cyclo-C H11 (6)]
6
2
3
The products were isolated from the reaction mix-
ture by column chromatography. All these com-
pounds have been characterized by elemental anal-
ysis (Table 1), H, C, P NMR, FT-IR, and mass
spectrometry. From the analogous reaction of 1 with
tert-butyl, cyclopentyl, iso-propyl, and ethylmagne-
sium bromide, no phosphorus compound could be
isolated.
i
3
2
1
13
31
loss of C
7
H
7
and C
8
9
H groups. The peak at m/z 423
(10%) with the expected isotope pattern shows the
In the reactions of halophosphazene with
organolithium or Grignard reagents, P N bond
cleavage can compete with halogen replacement
molecular ion for 4.
EXPERIMENTAL
General Remarks
[50]. The phosphoryl compounds 2, 3, and 5 also
result only from a P N bond cleavage.
The P N and P O stretching vibrations, 1220–
−
1
−1
Solvents were dried by conventional methods. All re-
actions were monitored by using Kieselgel 60 F254
1
338 cm and 1153–1263 cm respectively (Ta-
ble 2), are characteristic of phosphazenes. In the or-
der of 1, 4, 6, they are shifted to longer wavelengths.
The NMR data are presented in Tables 3–5. While
both phosphorus signals for 1 are observed at high
field, they move to lower field on alkyl substitution
(silica gel) precoated TLC plates and the separating
conditions were determined. The separation of prod-
ucts was carried out by flash column chromatogra-
phy using Kieselgel 60 (60–230 mesh).
1
3
IR spectra were recorded with an ATI Unicam
in 4 and 6 (Table 3). The C NMR signals of the
1
13
Mattson 1000 FTIR spectrophotometer. H, C, and
carbon atoms attached directly to phosphorus atoms
3
1
P NMR spectra were recorded using a Bruker DPX-
00 High Performance Digital FT-NMR spectrom-
4
eter operating at 400.13, 100.63, and 161.98 MHz,
respectively. All data were recorded for solutions in
TABLE 1 MS and Analytical Data of 2–6
1
13
CDCl
3
. The H and C chemical shifts were mea-
as an internal standard, and the
P chemical shifts were measured using 85% H PO
Mol. Weight a
%
sured using SiMe
4
3
1
Calcd
Found
Calcd Found
3
4
2
3
4
320
362
423
320
1 (C7H7 )
C
H
N
C
H
N
C
H
N
76.76
6.44
–
79.55
7.46
–
33.37
7.84
3.30
76.0
6.08
–
78.51
7.39
–
33.56
7.54
3.18
+
9
TABLE 3 31P NMR Data of 1–6
+
No M
1 (C7H7 ),
+
9
1
δ
δ
JPNP
PN
PO
05 (C H +)
8
9
423
1
2
3
4
5
6
−2.6
–
–
33.5
–
59.9
−10.6
41.8
47.2
−6.3
50.3
52.3
21.3
–
–
+
7
3 (SiC H9
)
3
5
6
218
507
218
–
3.4
–
a
aMolecular ion and only the first one or two peaks of MS in the relative
abundance order are shown.
aNot determined.

Reaction of N-Dichlorophosphoryl-P-trichlorophosphazene with Alkyl Grignard Reagents 415
TABLE 4 1H NMR Data of 2–6 (Coupling Constants J in Hz)
residue was chromatographed (R
f
= 0.52, chloro-
form/acetone 1:1). The white solid (compound 3) was
2
3
4
5
6
3.1 (CH2, 2 JPH: 13.8, 2H), 7.3–7.4 (5H)
◦
obtained in 7% yield, m.p. 154 C.
2.1 (2-H, 2H), 2.9 (1-H, 2H), 7.2–7.3 (5H)
2
0.3 (CH , 9H), 1.4 (CH , JPH: 16.2, 2H)
3
2
Reaction between 1
and Trimethylsilylmethylmagnesium Chloride
0.6 (4-H, 3H), 1.1 (3-H, 2H), 1.2 (2-H, 2H), 1.4 (1-H, 2H)
1.0–2.0 (20H), 3.9 (OPCH, 1H), 4.1 (NPCH, 1H)
Trimethylsilylmethylmagnesium chloride (34 ml,
1
M in ether) and 1 (1.80 g, 7 mmol, in 150 ml of
toluene) were used for the reaction as for 2. The
mixture was refluxed for 24 h, however. The residue
as an external standard. Chemical shifts downfield
from the standard are assigned positive δ values.
Electron impact mass spectra were obtained by Mi-
cromass UK Platform-II spectrometer. Microanaly-
sis was carried out by LECO 932 CHNS-O apparatus.
The starting material 1 was prepared by the method
of Emsley, Moore, and Udy and purified by vacuum
distillation [51].
was chromatographed (R
f
= 0.39, chloroform). The
white solid (compound 4) was obtained in 4% yield,
◦
m.p. 109 C.
Reaction between 1
and n-Butylmagnesium Bromide
n-Butylmagnesium bromide (24 ml, 2 M in ether)
and 1 (2.50 g, 9 mmol, in 150 ml of toluene) were
used for the reaction as for 2. The residue was chro-
Reaction between 1
and Benzylmagnesium Bromide
Benzylmagnesium bromide (17 ml, 2 M in THF) was
added dropwise to 1 (1.80 g, 7 mmol) in 150 ml of
toluene by stirring for 0.5 h at ambient temperature.
The mixture was then refluxed for 48 h. After the
matographed (R
f
= 0.39, chloroform). The viscous
compound (5) was obtained in 1% yield.
reaction was complete, the precipitated salt (MgBr
was filtered off and the solvent was removed under
2
)
Reaction between 1
and Cyclohexylmagnesium Bromide
vacuum. The residue was examined by TLC using
Cyclohexylmagnesium bromide (48 ml, 1 M in ether)
and 1 (2.50 g, 9 mmol, in 150 ml of toluene) were
used for the reaction as for 2. The residue was chro-
chloroform/acetone (3:1), R
by column chromatography. After the solvent was
f
= 0.66, and separated
removed, a white solid (compound 2) was obtained
matographed (R
f
= 0.53, chloroform/acetone 1:1).
◦
in 7% yield, m.p. 208 C.
The viscous compound (6) was obtained in 1% yield.
Reaction between 1
and 2-Phenylethylmagnesium Bromide
CONCLUSION
Tri- and pentasubstituted monophosphazenes were
isolated from the reaction between N-dichloro-
phosphoryl-P-trichloromonophosphazene and tri-
methylsilylmethylmagnesium chloride, and cyclo-
hexylmagnesium bromide, respectively. Phosphoryl
compounds formed due to a P N bond cleavage with
benzyl-, 2-phenylethyl-, and n-butylmagnesium bro-
mide. No phosphorus compound could be isolated
with tert-butyl-, cyclopentyl-, iso-propyl- and ethyl-
magnesium bromide.
2
-Phenylethylmagnesium bromide (40 ml, 1 M in
THF) and 1 (2.15 g, 8 mmol, in 150 ml of
toluene) were used for the reaction as for 2. The
TABLE 5 13C NMR Data of 2–6 (Coupling Constants J in
Hz)
1
5
2
35.9 (CH , JPC = 61.4), 127.4 (Cp, JPC = 2.5), 129.2
2
(
Cm, JPC = 1.9), 130.3 (Co, 3
4
J
= 5.0), 132.2 (C ,
PC
i
2
JPC = 6.7)
2
1
3
28.2 (2-CH , JPC = 3.0), 30.6 (1-CH , JPC = 62.5),
2
2
1
26.9 (Cp), 128.5 (Cm), 129.2 (Co), 141.3 (Ci )
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