Direct synthesis of cyclic and polymeric phosphazenes bearing diphenylphosphine groups and their complexes with [W(CO)5] fragments

Article abstract of DOI:10.1016/S0277-5387(99)00194-1

The reactions of the cyclotriphosphazenes [N₃P₃Cl₆] or [N₃P₃(O₂C₁₂H₈) ₂Cl₂] with the phenolic phosphine PPh₂(C₆H₄

Full text of DOI:10.1016/S0277-5387(99)00194-1

Polyhedron 18 (1999) 2853–2859
www.elsevier.nl/locate/poly
Direct synthesis of cyclic and polymeric phosphazenes bearing
diphenylphosphine groups and their complexes with [W(CO)5] fragments
*
´
´
´
Gabino A. Carriedo , Francisco J. Garcıa Alonso, Pedro A. Gonzalez, Paloma Gomez-Elipe
´
´
´
´
´
´
Departamento de Quımica Organica e Inorganica, Facultad de Quımica, Universidad de Oviedo, C/ Julian Claverıa S/N, 33071 Oviedo, Spain
Received 3 May 1999; accepted 30 June 1999
Abstract
The reactions of the cyclotriphosphazenes [N3P3Cl6] or [N3P3(O2C12H8)2Cl2] with the phenolic phosphine PPh2(C6H4-OH) in the
presence of Cs2CO3 give, respectively, the cyclic phosphazene phosphines [N3P3(OC6H4PPh2)6] (1) and
[N3P3(O2C12H8)2(OC6H4PPh2)2] (2), very pure and in high yield. The similar reaction with the linear polyphosphazene
h[NP(O2C12H8)]0.65[NPCl2]0.35jn in THF gives the diphenylphosphine polymer h[NP(O2C12H8)]0.65[NP(OC6H4PPh2)2]0.35jn (3). The
phenolic tungsten pentacarbonyl complex hW(CO)5[PPh2(C6H4-OH)]j reacts in the same way with those cyclic and polymeric
phosphazenes to give the corresponding complexes hN3P3[OC6H4PPh2-W(CO)5]6j (4), [N3P3(O2C12H8)2(OC6H4PPh2-W(CO)5)2] (5),
and h[NP(O2C12H8)]0.65[NP(OC6H4PPh2-W(CO)5)2]0.35jn (6).
1999 Elsevier Science Ltd. All rights reserved.
Keywords: Cyclophosphazenes; Polyphosphazenes; Phenolic phosphine; Macromolecular complexes; Carbonyls; Cesium carbonate
1. Introduction
es of this type are known where the main chain is a linear
polyphosphazene [-N=PR2]n [5]. Among those, there are a
few that bear transition metal–phosphine complexes [6,7]
(i.e. L5PPh2), some of which have been found to exhibit
useful catalytic properties [8].
Transition metal polymeric complexes are interesting for
many reasons, including their potential technological im-
portance [1]. The metal-containing polymers that consist
on a polymeric main chain with a pendant complex of a
MLn fragment attached through a spacer (Fig. 1) are of
interest for their relevance to catalysis [2,3], and other
possible applications [4]. A number of polymeric complex-
The most common synthetic route to these polymeric
complexes, starting from a chlorophosphazene precursor,
involves the multistep preparation of the polymer bearing
the PPh2 group (reactions (i)–(iii) in Scheme 1), followed
by a substitution reaction with a transition metal complex
having a labile ligand S (reaction (iv) in Scheme 1).
However, this method involves several difficulties. Thus,
in step (iii) some of the PPh2 sites are quaternized by the
BuBr formed in the lithiation step [9], and the substitution
reaction (iv) may be complicated by crosslinking caused
by the coordination to the same metal center of two PPh2
groups from different chains, giving rise to insoluble
materials [7].
Searching for other alternatives, we tried to introduce a
complex directly into the phosphazenes by means of the
replacement reaction indicated by (v) in Scheme 1.
We chose the fragment W(CO)5 because it is easily
coordinated to a PPh2 groups to give very stable complex-
es, and because it has a potential interest as a chromophore
for second harmonic generation [10].
Fig. 1. A linear polymer with a metal–ligand complex attached through a
spacer.
*Corresponding author. Tel.: 134-98-510-5009; fax: 134-98-510-
3446.
E-mail address: gac@sauron.quimica.uniovi.es (G.A. Carriedo)
In this paper we describe the preparation of cyclic and
0277-5387/99/$ – see front matter
PII: S0277-5387(99)00194-1
1999 Elsevier Science Ltd. All rights reserved.

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G.A. Carriedo et al. / Polyhedron 18 (1999) 2853–2859
Scheme 1.
polymeric phosphazenes bearing diphenylphosphine
groups and their [W(CO)5] complexes by this direct route,
consisting on the reaction of a phenolic phosphine
PPh2(C6H4-OH) or its complex hW(CO)5[PPh2(C6H4-
OH)]j with cyclic or polymeric chlorophosphazenes in the
presence of Cs2CO3.
phorus and tungsten analyses were performed by Galbraith
Laboratories. Gel-permeation chromatography (GPC) was
measured with Perkin-Elmer equipment with a model LC
250 pump, a model LC 290 UV, and a model LC 30
refractive index detector. The samples were eluted with a
0.1% by weight solution of tetra-n-butylammonium bro-
mide in THF through Perkin-Elmer PLGel (Guard 105, 104
and 103 A) at 308C. Approximate molecular weight
˚
2. Experimental
calibration was obtained using narrow molecular weight
distribution polystyrene standards. Tg values were mea-
sured with a Mettler DSC 300 differential scanning
calorimeter equipped with a TA 1100 computer, at 108C/
min. Thermal gravimetric analyses were performed on a
Mettler TA 4000 instrument. The polymer samples were
heated at a rate of 108C/min from ambient temperature to
8008C under constant flow of nitrogen.
2.1. General considerations
All the reactions were carried out under dry nitrogen.
K2CO3 and Cs2CO3 were dried at 1408C prior to use. The
acetone used as solvent was predistilled from KMnO4, and
distilled twice from anhydrous CaSO4. The THF was
treated with KOH and distilled twice from Na in the
presence of benzophenone. Petroleum ether refers to that
fraction with boiling point in the range 60–658C. The
4-hydroxy-phenyl diphenylphosphine (HO-C6H4-PPh2)
[11] was synthesised by reacting the known [12]
(CH3O)(CH3)2C-O-C6H4-Li with PClPh2 followed by
deprotection with aqueous HCl (see Experimental). The
hexachlorocyclotriphosphazene [N3P3Cl6] (Fluka) was
purified from hot petroleum ether and dried in vacuum.
The cyclic [N3P3(O2C12H8)2Cl2] was prepared as de-
scribed elsewhere [13]. The polymer [NPCl2]n was pre-
pared by heating the melted [N3P3Cl6] as described by
Allcock et al. [14].
2.2. Preparation of PPh2(C6H4OH)
A mixture of p-bromophenol (12.5 g, 72.2 mmol),
2-methoxypropene (13.8 ml, 144.5 mmol) and a drop of
POCl3 was stirred in the absence of light for 1 h. Four
drops of triethylamine were added and the volatiles were
evaporated in vacuo. The resulting pale yellow oil (very
light sensitive) was dissolved in petroleum ether (80 ml).
To this solution was added dropwise and with stirring a
solution of LiBu 2.5 M (31.8 ml, 79.42 mmol) in
petroleum ether (30 ml). The stirring was continued for 4 h
to give a white precipitate that was filtered and dried in
vacuo. The resulting solid was dissolved at 2708C in THF
(70 ml) and to the solution was added dropwise a solution
of PClPPh2 (8.4 ml, 47.04 mmol) in THF (30 ml). The
mixture was allowed to reach room temperature and stirred
overnight. Then, 20% aqueous HCl (36 ml) was added
and, after stirring for 3 h, the mixture was extracted with
diethyl ether (4350 ml). The extracts were stirred with an
excess of solid Na2CO3, washed with water (3350 ml),
The IR spectra were recorded with a Perkin-Elmer FT
Paragon 1000 spectrometer. NMR spectra were recorded
on Bruker AC-200 and AC-300 instruments, using CDCl3
as solvent unless otherwise stated. H and 13Ch1Hj NMR
1
are given in d relative to TMS. 31Ph1Hj NMR are given in
d relative to external 85% aqueous H3PO4. Coupling
constants are in Hz. C, H, N analyses were performed with
a Perkin-Elmer 240 microanalyzer. The chlorine, phos-

G.A. Carriedo et al. / Polyhedron 18 (1999) 2853–2859
2855
dried over Na2SO4, and filtered. The solvent was evapo-
rated in vacuo to give an orange oily residue that was
dissolved in CH2Cl2 and filtered through a column of
silica-gel. Evaporation of the solvent gave a white product
that was crystallized from CH2Cl2 /petroleum ether to give
PPh2(C6H4OH) as white microcrystals. Yield: 6 g (46%).
1H NMR 7.4–6.7 (m br, 14H, aromatic rings); 5.3 (s br,
1H, OH). 13C NMR 157.4 s, 136.5 (d, JPC521.6), 128.5 (d,
JPC58), 116.4 (d, JPC58.3) [P–C6H4]; 138.2 (d, JPC5
9.2), 134.1 (d, JPC519.3), 129.1 (d, JPC510.6), 129.0,
[PPh2]. 31P NMR 26.6. Found: C, 77.3; H, 5.5%. Calc. for
C18H15OP: C, 77.7; H, 5.4%.
was extracted with CH2Cl2 (4325 ml). The solution was
filtered and evaporated to dryness to give
[N3P3(O2C12H8)2(OC6H4PPh2)2] as a white solid. Yield
0.75 g, 81%. IR(nujol): n(PN)-region: 1243 m, 1171 s, br.
1H NMR 7.6–6.9 (m, br, aromatic rings). 13C NMR 151.9
(d, JPC57), 135.8 (d, JPC520.6), 134.5, 122.0 m. [P–
C6H4], 137.7 (d, JPC510.6), 134.3 (d, JPC519.5), 129.5,
129.2 (d, JPC57) [PPh2]; 148.6 m, 130.4, 130.2, 129.1,
126.7, 122.4 (O2C12H8). 31P NMR 25.8 [d, 2P,
P(O2C12H8)]; 10.0 [dd, 1P, P(OC6H4 –PPh2)2]; 26.1 (s,
2P, PPh2). Found: C, 67.8; H, 4.5; N, 3.9%. Calc. for
C60H44N3O6P5: C, 68.1; H, 4.2; N, 4.0%.
2.3. Preparation of hW(CO)5 [PPh2(C6H4-OH)]j
2.6. Preparation of
h[NP(O2C12H8 )]0.65 [NP(OC6H4PPh2 )2 ]0.35 jn (3)
To a solution of PPh2(C6H4OH) (1.6 g, 5.74 mmol) in
methanol (20 ml) was added
a
solution of
A mixture of [NPCl2]n (0.91 g, 7.86 mmol), 2,29-
HOC6H4 –C6H4OH (0.95 g, 5.11 mmol) and K2CO3 (2.82
g, 20.44 mmol) in THF (140 ml) was refluxed with
mechanical stirring for 10 h. Then, the phosphine
[PPh2(C6H4OH)] (1.57 g, 5.66 mmol) and Cs2CO3 (1.84
g, 5.66 mmol) were added, and the refluxing was con-
tinued for another 15 h. The resulting mixture was poured
into water (1.5 l) to give a precipitate that was washed
twice with water (1 l) and extracted with THF (300 ml).
The resulting solution was filtered through celite and
Na2SO4 and concentrated until a viscous liquid was
formed that was precipitated slowly into water (1.5 l). The
reprecipitation procedure was repeated in the same way
from THF/isopropyl alcohol, and THF/petroleum ether to
give a white solid that was dried in vacuo, first at room
temperature and then at 708C for 3 days. Yield: 1.4 g
(49.5%). The isolation procedure was carried out under the
laboratory atmosphere. IR(nujol): n(PN)-region: 1246 s,
1198 vs. 1H NMR d 7.4–6.6 (m, br, 16H, aromatic rings).
13C NMR: 152 br, 135.2 (d, JPC519.3), 121.7 br [P–
C6H4]; 138 br, 134.1 (d, JPC519.2), 129 br, [PPh2]; 149
br, 129.6 br, 125.6 br, 123 br, [O2C12H8]. 31P NMR 25.6
[m, P(O2C12H8)]; 26.1 (s, PPh2); 222.0 [m, PPh2)2].
Found: C, 67.2; H, 4.3; N, 3.9%. Calc. for
C20.4H15NO2P1.7: C, 68.3; H, 4.2; N, 4.2%, Chlorine
content: 0.07%. Mw(GPC): 160 000 (Mw /Mn5266) (see
text). Tg(DSC): 1158C (DCp50.21 J g21K21). TGA:
250.7% (5008C). Residue at 8008C: 38%.
[W(MeOH)(CO)5] obtained by irradiating with UV light
[W(CO)6] (2.0 g, 5.7 mmol) in methanol (90 ml) until the
carbonyl band at 1982 cm21 was no longer observed (¯4.5
h). The mixture was stirred at room temperature overnight
and filtered. The volatiles were removed in vacuo to give
hW(CO)5[PPh2(C6H4-OH)]j as a yellow solid that was
washed with hexane and dried in vacuo. Yield 2.9 g., 85%.
IR (CH2Cl2, cm21): n(CO): 2071 m, 1977 w, 1937 s. 1H
NMR 7.5–6.8 (m.br.,14H, aromatic rings); 5.7 (s.br., 1H,
OH). 13C NMR 198 br., 199 br, [W(CO)5]; 158, 136 (d,
JPC513.8), 116.4 (d, JPC511) [P–C6H4]; 133.4 (d, JPC5
11.9), 130.9, 129.3 (d, JPC59.7) [PPh2]. 31P NMR 19.5
(JPW5243 Hz). Found: C, 45.8; H, 2.3%. Calc. for
C23H15O6PW: C, 45.9; H, 2.5%.
2.4. Preparation of [N3P3(OC6H4PPh2 )6 ] (1)
A
mixture of [N3P3Cl6] (0.3 g, 0.86 mmol),
PPh2(C6H4 –OH) (1.45 g., 5.21 mmol) and Cs2CO3 (3.36
g, 10.31 mmol) in acetone (30 ml) was refluxed for 0.5 h.
The solvent was removed in vacuo and the residue was
extracted with CH2Cl2 (5320 ml). The solution was
filtered
and
evaporated
to
dryness to
give
[N3P3(OC6H4PPh2)6] as a white solid. Yield 1.4 g, 91%.
1
IR(nujol): n(PN)-region: 1212 m, 1187 m, 1160 s. H
NMR 7.6–6.9 (m br, aromatic rings). 13C NMR 151.6,
135.7 (d, JPC520.6), 134.6 (d, JPC512), 121.8 br [P–
C6H4]; 137.6 (d, JPC511), 134.2 (d, JPC519.5), 129.5,
129.2 (d, JPC57) [PPh2]. 31P NMR 8.8 (s, 3P, P3N3); 26.4
(s, 6P, PPh2). Found: C, 71.3; H, 4.5; N, 2.0%. Calc. for
C108H84N3O6P9: C, 72.1; H 4.7; N, 2.3%.
The product had traces (less than 2% in weight) of
1
PTHF (weak signals in the H NMR at 3.4 and 1.6). The
freshly prepared polymer had ¯8% of the PPh2 groups
oxidized to Ph2P=O (weak signal at 28.5 in the 31P NMR),
a fraction that increases on standing, specially during
handling in solution.
2.5. Preparation of [N3P3(O2C12H8 )2(OC6H4PPh2 )2 ] (2)
A mixture of [N3P3(O2C12H8)2Cl2] (0.5 g., 0.87 mmol),
PPh2(C6H4 –OH) (0.485 g., 1.74 mmol) and Cs2CO3
(1.135 g., 3.48 mmol) in acetone (40 ml) was refluxed for
0.5 h. The solvent was removed in vacuo and the residue
2.7. Preparation of hN3P3 [OC6H4PPh2-W(CO)5 ]6 j (4)
A
mixture of [N3P3Cl6] (0.11 g, 0.33 mmol),
hW(CO)5[PPh2(C6H4 –OH)]j (1.2 g, 1.99 mmol) and

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G.A. Carriedo et al. / Polyhedron 18 (1999) 2853–2859
Cs2CO3 (1.3 g, 3.96 mmol) in THF (20 ml) was refluxed
for 1 h. The solvent was removed in vacuo and the residue
was extracted with CH2Cl2 (5320 ml). The solution was
same way from THF/isopropyl alcohol, and THF/petro-
leum ether to give a yellow solid that was dried in vacuo,
at room temperature, for one week. Yield 0.6 g, 24%. The
isolation operations were carried out under the laboratory
atmosphere. IR: n(CO) (CH2Cl2): 2071 m, 1981 w, 1936
s, br (in THF: 2070, 1978, 1938). n(PN)-region (nujol):
1246 m, 1197 s. 1H NMR 7.8–6.2 (m br, aromatic rings).
13C NMR: 197.8 m, br [WCO5]; 152 br, 134 br, 121 br.
[P–C6H4]; 136 br, 133 br, 131 br, 129 [PPh2]; 149 br, 130
br, 126 br, 123 br, [O2C12H8]. 31P NMR 20.0 (s., PPh2 –W,
filtered
and
evaporated
to
dryness
to
givehN3P3[OC6H4PPh2 –W(CO)5]6j as a yellow solid.
Yield 1.05 g, 85%. IR: n(CO) (CH2Cl2): 2071 m, 1980 w,
1937 s, br. n(PN)-region (nujol): 1220 m, 1191 m, 1165 s.
1H NMR 7.5–7.0 (m br, aromatic rings). 13C NMR 199.5
hd, JPC(trans)522, 6COj; 197.7 hd, JPC(cis)57, JWC5126,
24COj[W(CO)5]; 152.4, 135 (d, JPC513), 132.7(d, JPC5
34), 121.4 (d, JPC510) [P–C6H4 –]; 136 (d, JPC540),
JPW5244); 25.0 [m, P(O2C12H8)]; 223.5 [m, P(OC6H4 –
133.5 (d, JPC512.1), 131.2, 129.4 (d, JPC510) [PPh2]. 31
P
PPh2 –W)2]. Found: C, 50.1; H, 2.6; N, 2.4; P, 9.9; W,
22.4%. Calc. for C23.9H15NO5.5P1. 7W0.7: C, 49.0: H, 2.6;
N, 2.6; P, 9.0; W, 21.9%. Chlorine content: 0.04%.
Mw(GPC): 1 700 000 (Mw /Mn54). Tg(DSC): 1278C.
NMR 20.5 (s, 6P, PPh2 –W, JPW5244 Hz); 7.6 [s, 3P,
P3N3]. Found: C 44.7; H, 2.3; N, 0.9%. Calc. for
C138H84N3O36P9W6: C, 44.3; H, 2.3; N, 1.1%.
(DCp50.08 J g21
K
21). TGA: 214% (150–3808C),
224% (4708C). Residue at 8008C:56%.
2.8. Preparation of hN3P3(O2C12H8 )2 [OC6H4PPh2-
W(CO)5 ]2 j (5).
The polymer had ¯7% of the PPh2 groups oxidized to
Ph2P=O. (weak signal at 28.5 in the 31P NMR).
A mixture of [N3P3(O2C12H8)2Cl2] (0.15 g., 0.26
mmol), [W(CO)5[PPh2(C6H4 –OH)]j (0.32 g., 0.53 mmol)
and Cs2CO3 (0.34 g., 1.04 mmol) in THF (30 ml) was
refluxed for 45 min. The solvent was removed in vacuo
and the residue was extracted with CH2Cl2 (5320 ml).
The solution was filtered and evaporated to dryness to
givehN3P3(O2C12H8)2[OC6H4PPh2 –W(CO)5]2j as a yel-
low solid. Yield 0.3 g, 68%. IR: n(CO) (CH2Cl2): 2071 m,
1981 w, 1938 s, br. n(PN)-region (nujol): 1229 m, 1173 s
br. 1H NMR 7.6–7.0 (m br, aromatic rings). 13C
NMR(CDCl3): 199.5 hd, JPC(trans)522, 2COj; 197.7 hd,
3. Results and discussion
Following the method described earlier for the synthesis
of other aryloxi phosphazenes [15], the hexachlorocyclot-
riphosphazene [N3P3Cl6] was reacted with six equivalents
of the phosphine phenol PPh2(C6H4OH) in refluxing
acetone in the presence of Cs2CO3 to give, in only 1/2 h,
the hexaphosphine derivative [N3P3(OC6H4PPh2)6] (1)
(Chart 1), that was obtained analytically and spectros-
copically pure, in 90% yield. The very short reaction time
required to obtain 1 is rather surprising taking into account
the size of the PPh2 groups [16,17]. This compound had
JPC(cis)57, JWC5126, 8COj [W(CO)5]; 152.9 (d, JPC57),
135.3 (d, JPC513), 132.6 (d, JPC542), 121.9 m, [OC6H4];
135.7 (d, JPC541), 133.4 (d, JPC512), 131.1, 129.3 (d,
JPC510) [PPh2]; 148.6 m, 130.4, 130.3, 129.1, 126.9,
122.4, [O2C12H8]. 31P NMR 25.6 [d, 2P, P(O2C12H8)];
20.7 (s, 2P, PPh2, JPW5244); 9.6 [dd, 1P, P(OC6H4 –
PPh2 –W)2]. Found: C, 49.3: H, 2.7; N, 2.3%. Calc. for
C138H84N3O36P9W6: C, 49.3; H, 2.6; N, 2.5%.
been
previously
prepared
[18]
starting
from
[N3P3(OC6H4Br)6] using the three step synthesis shown in
Scheme 1.
In a similar manner to [N3P3Cl6], the spirocyclic
phosphazene [13] [N3P3(O2C12H8)2Cl2] reacted with
PPh2(C6H4OH) and Cs2CO3 in refluxing acetone to give
the new diphosphine [N3P3(O2C12H8)2(OC6H4PPh2)2]
(2), in ¯80% yield (Chart 1). This reaction is also
surprisingly fast, requiring only 1/2 hour for completion.
This observation led us to extend the same technique to
synthesize the high molecular weight phosphazene
h[NP(O2C12H8)]0.65[NP(OC6H4PPh2)2]0.35jn (3) shown in
Scheme 2, which is the polymeric counterpart of 2. As
shown in Scheme 2, this random copolymer was obtained
by reacting first the poly(dichlorophosphazene) [NPCl2]n
with 2,29-dihydroxy-biphenyl (2,29-HOC6H4-C6H4OH)
and K2CO3 in THF [13] to give the partially substituted
intermediate h[NP(O2C12H8)]0.65[NPCl2]0.35jn that was
subsequently reacted with PPh2(C6H4OH) and Cs2CO3.
Both steps could be followed by 31P NMR to prove that no
crosslinked products were formed in the first step, and that,
the mechanism of the second step was non-geminal. The
product 3 is only sparingly soluble in THF.
2.9. Preparation of h[NP(O2C12H8 )]0.65 [NP(OC6H4PPh2-
W(CO)5 )2 ]0.35 jn (6)
A mixture of [NPCl2]n (0.57 g, 4.96 mmol), 2,29-HO-
C6H4-C6H4-OH (0.6 g, 3.23 mmol) and K2CO3 (1.8 g,
12.9 mmol) in THF (130 ml) was refluxed with me-
chanical stirring for
6
h. Then, the complex
[W(CO)5[PPh2(C6H4-OH)]j (3 g, 4.98 mmol) and
Cs2CO3 (2.1 g, 6.44 mmol) was added, and the reaction
was continued for another 16 h The resulting mixture was
poured into water (1.5 l) to give a precipitate that was
washed twice with water (1 l) and extracted with THF
(200 ml). Some material remained undissolved. The
extracts were filtered and concentrated until a viscous
liquid was formed that was precipitated slowly into water
(1.5 l). The reprecipitation procedure was repeated in the

G.A. Carriedo et al. / Polyhedron 18 (1999) 2853–2859
2857
Chart 1.
The analytical and spectroscopic data for the isolated
polymer (3) confirmed its composition and revealed that
the residual unreacted chlorine was very low (700 ppm).
No bands attributable to terminal OH groups were detected
in the IR spectrum. The 31P NMR proved the ratio of the
NP(O2C12H8)/NP(OC6H4PPh2)2 units, and showed that a
fraction (less than 8%) of the PPh2 groups (chemical shift
26.4 ppm) were oxidized to O=PPh2 (28.5 ppm). The
oxidation was observed to increase with time on standing
in the solid state (raising 27% in 2 years), showing that the
polymer is air sensitive (it becomes more insoluble and
fragmented). On the other hand, two weak signals at 3.4
and 1.6 ppm in the 1H NMR revealed that 3 contained
traces of poly tetrahydrofuran (PTHF), which is in accord
with previous observations made during the synthesis of
poly(2,29-dioxybiphenyl) phosphazenes in THF as solvent
[19].
Rather surprisingly, the GPC chromatogram of 3 was
weak and very broad showing several peaks corresponding
to Mw ranging from 23106 to 103. The estimated Mw was
(160 000) but the sample was extremely polydisperse (Mw /
Mn5266). Although this can be due in part to the low
solubility of this polymer, we found no convincing expla-
nation for this unusual behaviour.
Scheme 2.

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G.A. Carriedo et al. / Polyhedron 18 (1999) 2853–2859
The DSC curve showed a clear glass transition at 1158C
which is in the expected range for a polyspirophosphazene
random copolymer [13].
was in agreement with the analytical data, and also showed
that the product had 7% of the phosphine phosphorus as
Ph2P=O.
Similarly to the diphenylphosphine phenol, the tungsten
carbonyl complex hW(CO)5[PPh2(C6H4-OH)]j (formed
from [W(MeOH)(CO)5] and HO-C6H4-PPh2 in methanol
at room temperature) reacted very fast with the cyclophos-
phazenes [N3P3Cl6] or [N3P3(OC12H8)Cl2] and Cs2CO3 to
give respectively the phosphine complexes [N3P3hOC6H4-
PPh2-W(CO)5j6] (4) and [N3P3hOC6H4-PPh2-W(CO)5j2
(O2C12H8)2] (5) (Chart 2) in high yield and purity.
Both complexes were fully characterized by the ana-
lytical and spectroscopic data given in the Experimental
section. Interestingly, the chemical shift of the ring phos-
phorus atoms in 4 are significantly lower than those of the
related hexaphosphine 1, which is in accord with earlier
observations in other polymetallic cyclophosphazene com-
plexes [20–22].
The above reactions were extended to the synthesis of
polyphosphazenes carrying diphenylphosphine complexes
of W(CO)5. Thus, we found that the polymer
h[NP(O2C12H8)]0.65[NPCl2]0.35jn (see Scheme 2), reacts
with the phenolic complex hW(CO)5[PPh2(C6H4-OH)]j in
the presence of Cs2CO3 to give the very stable and soluble
polymeric complex h[NP(O2C12H8)]0.65[NP(OC6H4PPh2-
W(CO)5)2]0.35jn (6). The very low residual chlorine in the
final product (below 0.05%) indicated the high efficiency
of the substitution reaction, and the analytical purity after
several reprecipitation steps from water, methanol and
petroleum ether, all conducted under air, showed that the
complex is rather stable. However, the yield was only
24%.
In sharp contrast with the phosphine polymer 3, the
GPC of 6 showed little polydispersity, with a Mw of
1 700 000 and polydispersity index of only 4. The glass
transition temperature (1278C) was ¯108C higher than that
of 3, in accord with the expected increase originated in the
incorporation to the polymer of metallic fragments [23].
The DCp (0.08) was low, suggesting a high degree of
crystallinity. The TGA curve showed two weight losses
between 150–3808C (14%) and at 4708C (24%), but the
final residue at 8008C was rather high (56%). Although
those thermograms measure only the apparent thermal
stability (which depends on the heating rate), this type of
behaviour suggests that 6 is a rather stable material,
although is somewhat easily oxidized by air.
In spite of the presence of Ph2P=O groups in 3 and 6,
and the low yield in the latter, these results open a new
route for the preparation of phosphazene–phosphine and
their complexes, both cyclic and polymeric, by the direct
reaction of a chlorophosphazene and a phenol of the
general type LnM-Ph2PC6H4-OH. The mild conditions
required in those reactions might allow the use of moder-
ately stable phenolic complexes. Examples of this type of
direct approach to the synthesis of metal-containing high
molecular weight phosphazenes are very scarce. Thus,
cyclic and polymeric phosphazenes with pendant
[Cr(CO)3(h6-C6H5O)] (also air sensitive) groups have
been prepared by reacting the corresponding chloro-
phosphazenes with the sodium salt [Cr(CO)3(h6-
C6H5ONa)] [24].
The IR (nCO absoptions at 2071 m, 1981 w, and 1936 s,
br), 13C NMR (diluted) and 31P NMR spectra clearly
showed the presence of the PPh2P-W(CO)5 groups. The
31P NMR spectrum allowed a measurement of the ratio of
NPhOC6H4-PPh2-W(CO)5j2 and NP(O2C12H8) groups that
Finally, it is worth noting that the reaction of polymer 3
with [W(MeOH)(CO)5] lead to a brown precipitate differ-
ent to the soluble complex 6 (Scheme 2). The solid state
IR spectrum of this insoluble material showed not only the
carbonyl signals expected for the Ph2P-W(CO)5 fragments,
Chart 2.

G.A. Carriedo et al. / Polyhedron 18 (1999) 2853–2859
2859
[7] H.R. Allcock, K.D. Lavin, N.M. Tollefson, T.L. Evans, Or-
ganometallics 2 (1983) 267.
[8] R.A. Dubois, P.E. Garrou, K.D. Lavin, H.R. Allcock, Organometal-
lics 5 (1986) 460.
[9] H.R. Allcock, T.J. Fuller, T.L. Evans, Macromolecules 13 (1980)
1325.
but also other bands at 2016, 1889 and 1847 that most
likely correspond to W(CO)4 fragments. This shows the
coordination to the same tungsten atom of two PPh2
groups, explaining the formation of the insoluble (cross-
linked) polymer.
[10] P.G. Lacroix, W. Lin, G.K. Wong, Chem. Mater. 7 (1995) 1293.
[11] A.E. Senear, W. Valient, J. Wirth, J. Org. Chem. 25 (1960) 2001.
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Organometallics 11 (1992) 1742.
Acknowledgements
´
´
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[13] G.A. Carriedo, L. Fernandez-Catuxo, F.J. Garcıa Alonso, P. Gomez
We are grateful to the Spanish DGICYT (Project PB94-
1346), to the European Commission (Project BRRT-CT97-
0083) for financial support and the University of Oviedo
´
Elipe, P.A. Gonzalez, Macromolecules 29 (1996) 5320.
[14] H.R. Allcock, R.L. Kugel, K.J. Valan, Inorg. Chem. 5 (1966) 1709.
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Commun. 18 (1997) 371.
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Dalton Trans. (1992) 1687.
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(Vicerrectorado de Investigacion) for a grant.
[17] P.E. Austin, G.H. Riding, H.R. Allcock, Macromolecules 16 (1983)
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