Phosphorus-nitrogen compounds: New spiro-cyclic phosphazene derivatives. Structure of 4′,4′,6′,6′-tetrachloro-3,4-dihydro-3-(3- methylpyridin-2-yl)spiro-[1,3,2-benzoxazaphosphinine-2,2′- (2λ5,4λ5,6λ5- cyclotriphosphazene)]

Article abstract of DOI:10.1016/j.molstruc.2005.05.039

The condensation reactions of {N-[(2-hydroxyphenylmethyl)amino]- methylpyridines (5-8) with trimer, N₃P₃Cl₆, have been afforded partially substituted novel spiro-cyclic phosphazene derivatives (9-12) (Scheme 1). Compounds

Full text of DOI:10.1016/j.molstruc.2005.05.039

Journal of Molecular Structure 753 (2005) 84–91
www.elsevier.com/locate/molstruc
Phosphorus-nitrogen compounds: New spiro-cyclic phosphazene
derivatives. Structure of
40,40,60,60-tetrachloro-3,4-dihydro-3-(3-methylpyridin-2-yl)-
spiro-[1,3,2-benzoxazaphosphinine-2,20-
(2l5,4l5,6l5-cyclotriphosphazene)]. Part XII
a
b
a
b
Hakan Dal , Serap Safran , Yasemin Su¨zen , Tuncer Hokelek , Zeynel Kılıc¸
c,
*
¨
a
˘
Department of Chemistry, Faculty of science, Anadolu University, 26470 Yenibaglar, Eskis¸ehir, Turkey
bDepartment of Physics, Hacettepe University, 06800 Beytepe, Ankara, Turkey
˘
Department of Chemistry, Faculty of science, Ankara University, 06100 Tandogan, Ankara, Turkey
c
Received 11 April 2005; revised 20 May 2005; accepted 23 May 2005
Available online 21 July 2005
Abstract
The condensation reactions of {N-[(2-hydroxyphenylmethyl)amino]-methylpyridines (5–8) with trimer, N3P3Cl6, have been afforded
partially substituted novel spiro-cyclic phosphazene derivatives (9–12) (Scheme 1). Compounds (9–12) have been characterized by
elemental analyses, FTIR, 1H–, 13C–, 31P-NMR, HETCOR, and MS. The structure of the spiro-cyclic phosphazene (9) has been examined
˚
˚
˚
crystallographically. It crystallizes in the P21/n space group with aZ10.7906(10) A, bZ8.5625(17) A, cZ21.187(5) A, bZ91.298(12)8, VZ
1957.1(6) A , ZZ4 and DxZ1.660 g cmK3. The structure consists of a non-planar phosphazene ring with a bulky methylpyridinyl and a
3
˚
benzo-fused spiro-cyclic side group. The six-membered spiro-cyclic ring has a twist-boat conformation.
q 2005 Elsevier B.V. All rights reserved.
Keywords: spiro-Phosphazenes; Crystal structure of phosphazenes; Partially substituted phosphazenes; Spectroscopic studies of phosphazenes
1. Introduction
rechargeable lithium batteries [9,10], and besides their
multidimensional use as biomedical materials [11].
In recent years, we are currently investigating the
chemistry of bulky bifunctional reagents with trimeric
phosphazene, N3P3Cl6 [12,13]. The condensation reactions
of bifunctional reagents, such as methylenebis(4-nitro-
phenol) [14,15], N2Ox (xZ2,3) donor type aminopodands
and diazacrown ethers [12,13,16], with cyclotriphospha-
zene, N3P3Cl6, can give rise to several structural
architectures: spiro, ansa, spiro–ansa, bino and open
chain. For example, the reaction of methylenebis(4-
nitrophenol) and bifunctional aminopodands with
N3P3Cl6, gave spiro-, ansa, spiro–ansa, in which ansa
derivative is the major product, and spiro-, ansa-, bino
derivatives, in which spiro- derivatives are by far the major
product, respectively, [14,15,17]. While the spiro-products
have been isolated from the reaction of diazacrown ethers
with N3P3Cl6 [12,13]. It is shown that, the distribution of
products may be depend on the solvent polarity [17]. On the
other hand, there have also been appeared some nice papers
In the last four decades, phosphazene derivatives have
been focussed attention of considerable interest for a
number of reasons: (i) the general preparative chemistry
of a structurally relative simple trinuclear compound with
the phosphorous nuclei in different chemical environments;
(ii) for producing inorganic polymers with different organic
and inorganic side groups [1]; (iii) for the investigation of
the stereogenic properties of phosphazenes [2,3] and the
further design of the highly selective anticancer [4],
antibacterial [5] and anti-HIV [6] agents. On the other
hand, they have also found applications in producing non-
burning textile fibers, advanced elastomers [7,8],
*
Corresponding author. Tel.:C90 3122126720; fax: C90 3122232395.
E-mail address: zkilic@science.ankara.edu.tr (Z. Kılıc¸).
0022-2860/$ - see front matter q 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2005.05.039

D. Hakan et al. / Journal of Molecular Structure 753 (2005) 84–91
85
R
1
R
1
OH
OH
N
N
H
C
2
H
C
R
2
R
2
NaBH / dryMeOH
4
N
N
H
R
3
R
R
4
R
4
3
Schiffbases
Corresponding amine
R
N
N
R
2
1
R
1
Cl
Cl
Cl
Cl
N
R
3
OH
N
P
P
H
2
C
N
P
N
R
2
N
P
N
H
Cl
R
4
+
Cl
Cl
P
P
CH
2
N
R
4
R
3
N
Cl
O
Cl
Cl
Schiff bases
Corresponding amine
Corresponding phosphazene
R1
H
R2
H
R3
H
R4
CH3
9
1
2
3
4
5
6
7
8
10
11
12
H
H
H
CH3
H
H
CH3
H
H
CH3
H
H
Scheme 1.
in the literature about the reactions of bifunctional reagents
with fluoro and chloro phosphazenes [18–20], and it is
reported that in these reactions ansa-, spiro-, ansa–spiro-
and bisansa-substituted fluorinated cyclophosphazenes
have been obtained. It was claimed that the ansa-derivatives
readily transformed to the spiro-compounds in the presence
of fluorinated or non-fluorinated bases, while the analogous
tetrachloro ansa-skeletons had not been transformed
[21,22].
carried out under argon atmosphere. The solvents, benzene
and dichloromethane, were dried by standard methods prior
to use and kept under argon atmosphere. Melting points
were measured on a Gallenkamp apparatus using a capillary
tube. Melting points are uncorrected. 1H–, 13C–, and
31P-NMR spectra were obtained on a Bruker DPX FT-
NMR (400 MHz) spectrometer (SiMe4, as internal standard
and 85% H3PO4 as an external standard). FTIR spectra were
recorded on a Jasco 300E FTIR spectrometer in KBr discs
and were reported in cmK1 units. Microanalyses were
In the present work, the reaction of bulky aminophe-
nols,{N-[(2-hydroxyphenylmethyl)-amino]-methylpyri-
dines (5–8), which are obtained from the reduction of the
corresponding Schiff bases (1–4), with N3P3Cl6 were
investigated and four isomeric spiro-phosphazene deriva-
tives (9–12) have been isolated (Scheme 1). The structures
of compounds (9–12) are determined by elemental analyses,
1H–, 13C–, 31P-NMR, HETCOR, FTIR and MS spectral
data. The salient features of spectral data of these
compounds have been discussed. The crystal structure of
compound (9) was confirmed by single-crystal X-ray
diffraction techniques.
¨ ˙
carried out by the microanalytical service of TUBITAK-
ATAL Ankara (Turkey). Electrospray ionization mass
spectrometric (ESI-MS) analyses were performed on the
AGILEND 1100 MSD spectrometer.
2.2. Synthetic procedures
2-[(1E)-2-aza-2-(4-methyl(2-pyridyl))ethenyl]benzen-1-
ol (2) and 2-[(1E)-2-aza-2-(6-methyl(2-pyridyl))ethenyl]
benzen-1-ol (4) have been prepared according to the
published prodecure [23], m.p. 101 8C [lit. m.p. 86–87 8C]
and m.p. 105 8C [lit. m.p. 98 8C], respectively. 2-[(1E)-2-
aza-2-(3-methyl(2-pyridyl))ethenyl]benzen-1-ol (1) and 2-
[(1E)-2-aza-2-(5-methyl-(2-pyridyl))ethenyl]benzen-1-ol
(3) have been obtained using a method in which
salicylaldehyde and appropriate methyl-2-aminopyridines
are refluxed in MeOH (50 mL), m.p. 89 8C for 1 and m.p.
69 8C for 3.
(N-[(2-Hydroxyphenylmethyl)amino]-3-methylpyridine)
(5): 2-[(1E)-2-aza-2-(6-methyl(2-pyridyl))ethenyl]benzen-
1-ol (1) (6.36 g, 30.0 mmol) in MeOH (50 mL) was refluxed
for 1 h and then equimolar amount of sodium borohydride
(1.13 g, 30.0 mmol) were partially added. The reduction
was completed after 2 h. Then the solvent was evaporated in
2. Experimental
2.1. Reagents and techniques
Hexachlorocyclotriphosphazatriene, N3P3Cl6, was pur-
chased from Aldrich and recrystallised from dry hexane
followed by sublimation twice before use.
2-Hydroxybenzaldehyde, aminopyridines and sodium bor-
ohydride were purchased from Fluka and used directly.
Tetrahydrofuran, n-hexane and benzene were distilled from
calcium hydroxide. All experimental manipulations were

86
D. Hakan et al. / Journal of Molecular Structure 753 (2005) 84–91
reduced pressure. The residue was dissolved in dichlor-
omethane and washed with water. Compound (5) was
crystallized from chloroform/n-hexane (1:1), yield 5.45 g,
85 %, m.p. 98 8C.
C 31.93, H 2.47, N 14.32; found: C 32.57, H 2.39, N 14.12
for (12).
2.3. Crystallography
(N-[(2-Hydroxyphenylmethyl)amino]-4-methylpyridine)
(6), (N-[(2-hydroxyphenylmethyl)amino]-5-methylpyridine)
(7) and (N-[(2-hydroxyphenylmethyl)amino]-6-methylpyri-
dine) (8): The work-up procedures of these compounds are
as in compound (5); yields 5.13 g, 80 %, m.p. 133 8C;
3.85 g, 60 %, m.p. 141 8C and 4.75 g, 74 %, m.p. 111 8C,
respectively.
The suitable crystals of compound (9) for X-ray analysis
were obtained by recrystallisation from dichloromethane/
n-hexane (1:1) mixture. Experimental data, methods and
procedures used to elucidate the structure and other related
parameters are given in Table 1. An empirical absorption
correction based on a series of psi-scans was applied [24].
The structure was solved by direct methods, SHELXS-97 [25].
Since the difference synthesis did not clarify the positions
of H atoms, they were placed in calculated positions at
40,40,60,60-Tetrachloro-3,4-dihydro-3-(3-methylpyridin-
2-yl)spiro-[1,3,2-benzoxazaphosphinine-2,20-(2l5,4l5, 6l5-
cyclotriphosphazene)] (9): N-[(2-Hydroxyphenylmethyl)
amino]-6-methylpyridine (1.29 g, 6.06 mmol) in benzene
(100 mL) and triethylamine (2.53 mL, 18.18 mmol) were
slowly added to the solution of trimer (2.10 g, 6.06 mmol) in
benzene (40 mL). It was stirred and refluxed with argon
being passed over the reaction mixture, at K15 8C. After
1 h, the mixture was allowed to come to an ambient
temperature. Then, the precipitated salts were filtered off
and the solvent was evaporated under reduced pressure. The
compound (9) was crystallized from dichloromethane/
n-hexane (1:1), yield 1.84 g, 58 %, m.p. 158 8C, RfZ0.54
[CH2Cl2/n-hexane (3:1)], anal. calc. for C13H12Cl4N5OP3:
C 31.93, H 2.47, N 14.32; found: C 32.31, H 2.61, N 13.96.
40,40,60,60-Tetrachloro-3,4-dihydro-3-(4-methylpyridine-
2-yl)spiro-[1,3,2-benzoxazaphosp-hinine-2,20-(2l5,4l5,6l5-
cyclotriphosphazene)] (10): N-[(2-Hydroxyphenylmethyl)
amino]-4-methylpyridine (0.59 g, 2.76 mmol) in aceto-
nitrile (100 mL) was slowly added to triethylamine
(1.20 mL, 8.28 mmol) with argon being passed over the
reaction mixture at K15 8C. After 1 h, the mixture was
allowed to come to an ambient temperature, and trimer
(0.96 g, 2.76 mmol) in acetonitrile (40 mL) was added to
this mixture by stirring. The mixture was refluxed for 2 h
continuously. Then, the precipitated salts were filtered off
and the solvent was evaporated under reduced pressure. It
was crystallized from dichloromethane/n-hexane (1:1),
yield 0.73 g, 51%, m.p. 239 8C, RfZ0.60 [CH2Cl2/n-hexane
(3:1)], anal. calc. for C13H12Cl4N5OP3: C 31.93, H 2.47, N
14.32; found: C 32.28, H 2.67, N 13.98. EI-MS (fragments
based on 35Cl, Ir %): m/z 488 ([MCH]C, 10)
40,40,60,60-Tetrachloro-3,4-dihydro-3-(5-methylpyridin-
2-yl)spiro-[1,3,2-benzoxazaphosphinine-2, 20-(2l5,4l5,
6l5-cyclotriphosphazene)] (11) and 40,40,60,60-tetrachloro-
3,4-dihydro-3-(6-methyl-pyridin-2-yl)spiro-[1,3,2-benzox-
azaphosphinine-2, 20-(2l5,4l5,6l5-cyclotriphosp-hazene)]
(12): The work-up procedures were as in compound (9).
They were crystallized from dichloromethane/n-hexane
(1:1), yield 0.49 g, 53%, m.p. 208 8C, RfZ0.71 [THF/CH2-
Cl2/n-hexane (2:1:1)], anal. calc. for C13H12Cl4N5OP3: C
31.93, H 2.47, N 14.32; found: C 32.33, H 2.66, N 13.90. EI-
MS (fragments based on 35Cl, Ir %): m/z 488 ([MCH]C, 10)
for (11) and yield 5.58 g, 60%, m.p. 202 8C, RfZ0.72
[CH2Cl2/n-hexane (2:1)], anal. calc. for C13H12Cl4N5OP3:
Table 1
Experimental data
Compound
C13H12Cl4N5OP3
colourless\rod shaped
488.99
Colour/shape
For. wt.
Space group
Temperature (K)
Cell constants
P 21/n
296(2)
˚
˚
aZ10.7906(10) A, bZ8.5625(17) A,
˚
cZ21.187(5) A, bZ91.298(12)8
1957.1(6)
3
Cell volume (A )
˚
Formula units/unit cell
calc (Mg mK3
4
D
)
1.660
mcalc (mm-1)
7.960
Diffractometer/scan
Radiation used, graphite
monochromator
Enraf–Nonius CAD-4/wK2q
˚
Cu Ka (lZ1.54180 A)
Max. crystal dimen. (mm)
Standard reflections
Decay of standards (%)
Reflections measured
qmax (8)
0.35!0.15 !0.15
3
!1
4168
74.25
Range of h, k, l
K13!h!13; 0!k!10; K26!l!0
2746
Number of reflections with IO
2s(I)
Corrections applied
Computer programs
Lorentz-polarization
SHELXS-97 [25], SHELXL-97 [25],
ORTEP-3 [26]
Source of atomic scattering
Int. Table for X-Ray Cryst. Vol. IV,
factors
1974 [27]
Direct methods
Geometric calculation
236
Structure solution
Treatment of hydrogen atoms
No. of parameters var
GOF
1.021
0.0642
RZjjFojKjFcjjj=jFoj
Rw
0.1641
Rint
0.0941
-3
˚
K3
Drmax (e A )
0.819
˚
Drmin (e A
CCDC numbera
)
0.631
268227
a
Supplementary crystallographic data have been deposited with the
Cambridge Crystallographic Data Centre (CCDC deposition number
268227). These data can be obtained free of charge via http://www.ccdc.
cam.ac.uk/conts/retrieving.html (or from the Cambridge Crystallographic
Data Center, 12 Union Road, Cambridge CB2 EZ, UK; fax:
C44(1223)336033; e-mail: deposit@ccdc.cam.ac.uk).

D. Hakan et al. / Journal of Molecular Structure 753 (2005) 84–91
87
˚
distances of 0.93 (CH), 0.97 (CH2) and 0.96 A (CH3), and
allowed to ride on their attached atoms.
were critical for monitoring the degree to which the chlorine
atoms in hexachlorocyclotriphosphazene had been substi-
tuted with bulkly spiro-cyclo N-methyl pyridine groups.
31P-NMR spectra show AX2 spin systems. According to the
pattern of proton coupled 31P-NMR spectra of compounds
(9–12), it is concluded that the only spiro-architectures are
possible. The chemical shifts are highly sensitive to the
changes in the exocyclic NPN angles [30,31], thus the small
variations in the angles can deviate chemical shifts,
significantly as observed in the compounds (9–12)
(Table 3). However, it seems that the dPspiro values depend
on the positions of the CH3 group, in these compounds.
The 1H- and 13C-NMR data are listed in Table 3.
HETCOR-NMR experiments of these compounds (9–12)
are very useful for the assignments of the chemical shifts of
all the protons and carbons. As an example, only the
HETCOR spectrum of compound (12) is depicted in Fig. 1.
The Ar-CH2-N- protons are observed between dZ4.79–
5.02 ppm as doublets, in which those have three bond-
3. Results and discussion
3.1. Synthesis and spectroscopic studies
All Schiff bases (1–4) have been prepared from the
reactions of appropriate substituted 2-aminopyridines with
salicylaldehyde in MeOH. The Schiff bases were reduced by
NaBH4 in methanol. The reactions of N3P3Cl6 with the
equimolar amounts of bulky corresponding amines (5–8) in
benzene (in MeCN for 10) in the presence of NEt3 afford
partially substituted phosphazene derivatives (9–12).
Although a number of reactions of primary and secondary
amines and phenols with N3P3Cl6 have been investigated
[28,29], studies of the reactions of N3P3Cl6 with bulky
aminophenols, which are bifunctional ligands, are highly
limited [13]. The reactions of bulky aminophenols (5–8)
with N3P3Cl6 in benzene and acetonitrile (for compound 10)
afford dominantly the spiro-architectures [yields: 58% for
(9), 51% for (10), 53% for (11) and 60% for (12)] as in the
reactions of diazacrown ethers with N3P3Cl6 [12,13], in
contrast to the several expectations of phosphazene
derivatives (e.g. spiro, ansa, spiro–ansa, bino and open
chain products) [14,15,17]. The ESI-MS spectra of
compounds (9–12) show the protonated [MCH]C and
deprotonated [MKH]Cmolecular ion peaks. The elemental
analyses results are in agreement with the proposed
structures.
3
coupling constants, wca. JPHZ12.9 Hz.
All of the possible carbon peaks are observed from the
13C NMR spectral data, as expected. The four bond coupling
4
constants, JPC, of Ar–CH2–N are found wca. 6.5 Hz. It is
interesting that the two bond coupling constants, 2JPC, of C5
carbons of all the compounds are observed between 7.4 and
7.8 Hz, which are larger than those of the C7 carbons.
3.2. Crystal studies
The molecular structure of compound (9) along with the
atom-numbering scheme is depicted in Fig. 2(a). It consists
of a trimeric phosphazene ring with spiro-cyclic bulky NO
and N-3-methylpyridine substituents. The phosphazene,
A(P1/N1/P2/N2/P3/N3), ring is not planar having a total
Selected FT-IR frequencies of various diagnostic bands
for the compounds (5–12) are given in Table 2. In the FT-IR
spectra of the compounds characteristic nN-H and nC-H
stretching bands are observed between 3391K3313 cmK1
for (5–8) and 3069K3033 cmK1 for (5–12). The absorption
bands assignable to the stretching of the –PZN-and P-Cl
bonds for compounds (9–12) were observed at frequency
ranges of [(1159–1247) and (517–578)] cmK1. These data
are in accordance with the reported values for phosphazene
derivatives [16].
˚
puckering amplitude, QT of 0.503(15) A [32] and a flattened
boat form [Fig. 2(b); f2Z125.9(1.2)8 and q2Z59.0(3)8].
Ring A has a pseudo-mirror plane passing through atoms N1
and P3, as can be deduced from the torsion angles (Table 4).
Atoms N1, N2 and N3 are displaced from the plane through
˚
the P atoms by K0.030(4), 0.103(4) and 0.131(3) A,
respectively. The six-membered ring B(P3/N4/C7/C8/C13/
The proton decoupled 31P-NMR spectral data of spiro-
phosphazenes (9–12) are given in Table 3. 31P-NMR spectra
˚
O1) has a total puckering amplitude of 0.616(4) A [32] and a
twist-boat form f2ZK157.6(4)8 and q2Z104.7(5)8].
Table 2
Selected IR bands
Compound
y (N–H)
y (C–H) arom
y
y (CZC)
y (PZN)
y (P–Cl)
(C–H) alip
5
3391 vs
3056 m
3058 m
3033 m
3034 m
3063 m
3065 m
3036 m
3069 m
2923;2851 s
2919;2867 m
2915;2863 m
2923;2881 s
2912;2854
2869;2921
2851;2920
2922;2957
1613 vs
1585 vs
1581 s
1589 s
1582 vs
1606
–
–
6
3313 vs
–
–
7
3343 vs
–
–
8
3331 vs
–
–
9
–
–
–
–
1186–1214
1173–1247
1185–1244
1159–1247
520;577
520;574
519;578
517;572
10
11
12
1604
1602
Abbreviations: s strong; m medium; v very.

Table 3
1
31P-, H- and 13C-NMR spectral data in CDCl3
2
Compound
d ( A )
d ( B )
JPNP
H1
H2
H3
H4
–
H5
H6
H7,8
CH2
CH3
9
5.15 (t)
26.32 (d)
57.3
8.33(d,1H)3
JHHZ4.3
7.3 (t,1H)3
JHHZ6.6
7.05 (d,1H)3
JHHZ5.1
–
7.60(d,1H)3
JHHZ7.6
–
7.13–7.28
7.13–7.28
7.13–7.28
4.70(d,2H)2
JPNCHZ16.9
5.02(d,2H)2
JPNCHZ12.8
4.58(d,2H)2
JPNCHZ12.9
4.79(d,2H)2
JPNCH Z12.9
2.31(1H)
10
11
12
2.76 (t)
2.67 (t)
1.66 (t)
27.15 (d)
27.09 (d)
25.27 (d)
61.5
61.7
62.6
8.42 (d,1H)3
JHHZ5.1
8.01(1H)
6.97 (d,1H)
7.42(dd,1H)3
JHHZ7.4
7.48(t,1H)3
JHHZ4.6
7.39–7.62(m,2H)
7.07–7.09(m,2H)
7.24–7.26(m,2H)
2.61(1H)
2.11(1H)
2.60(1H)
7.34(d,1H)3
JHHZ8.4
6.65(d,1H)3
JHHZ8.5
7.02(dd,1H)3
JHHZ7.4
7.18(t,1H)3
JHHZ7.9
–
6.88 (d,1H)3
7.62 (t,1H)3
JHHZ8.1
6.75(d,1H)3
JHHZ8.3
7.21(dd,1H)3
JHHZ7.4
7.40(t,1H)3
JHHZ7.8
JHHZ7.5
Compound C1
C2
C3
C4
–
C5
C6
C7
C8
C9
C10
C11
CH2
43.0
CH3
21.8
9
148.5
117.5
138.6
124.6
151.42JPCZ 4.1
–
118.84JPC Z 6. 127.6
129.8
126.3
8
10
11
12
147.6
148.1
157.6
119.4
127.4
117.9
150.5
139.5
138.4
109.63JPCZ6.3
108.43JPCZ6.1
106.03JPCZ8.9
124.73JPCZ7.8
124.73JPCZ7.6
124.83JPCZ7.4
150.52JPCZ4.3
149.43JPCZ8.1
149.43JPCZ8.3
149.13JPCZ8.2
119.64JPCZ6.5
119.74JPCZ6.4
119.14JPCZ6.4
127.2
127.2
126.8
130.1
130.1
129.7
125.5
125.5
125.1
47.5
47.6
47.7
22.5
19.4
22.0
153.02JPCZ4.3
154.62JPCZ4.2
Chemical shifts (d) are reported in ppm. d: doublet; dd: doublet of doublet, t: triplet; m: multiplet. J values are reported in Hz.

D. Hakan et al. / Journal of Molecular Structure 753 (2005) 84–91
89
1
Fig. 1. The HETCOR spectrum resulted from long range H-13C connectivities on compound (12).
˚
The average P–N bond length in ring (A) is 1.578(4) A,
˚
which is shorter than the exocyclic P3–N4 [1.660(3) A]
bond. The P–N bond lengths are in the range 1.564(3)–
˚
1.597(4) A and have an irregular variation on the distance
from atom P3 in the ring, such that P3–N2OP3–N3OP2–
N1OP1–N1zP2–N2OP1–N3 (Table 4). The P–N bond
angles and the deviation of ring A from planarity seems to
agree with the postulated ‘island delocalization’ model for
phosphazenes [33,34]. It has already been shown that simple
cyclotriphosphazenes with ‘island delocalization’ have a
highly polarized structures, close to a zwitterion form
[35,36]. Zwitterion form means that endocyclic P–N bonds
of phosphazene ring are very polar in character, PC–NK,
indicating that charges on P and N atoms are separated and
caused shortening of P–N bonds. The spiro-cyclic sub-
stituent provides an additional force to create the postulated
zwitterionic form. The sum of the bond angles around atom
N4 [357.8(3)8] shows that the N4 atom has a nearly planar
geometry.
In ring (A), the endocyclic N2–P3–N3 [116.6(2)8] angle
is smaller than, and the exocyclic O1–P3–N4 [100.3(2)8]
angle is nearly the same as those of the ‘standard’ compound
N3P3Cl6 [37]; these values are in agreement with electron
donation and withdrawal by the substituents in compound
(9). In N3P3Cl6, the corresponding angles are
118.3(2),118.5(3)8 and 101.2(1),101.6(1) 8 , respectively.
The P2-N2-P3 and P3-N3-P1 bond lengths in compound (9)
are 120.5(2) and 121.8(2)8, respectively, while the P1–N1–
P2 angle [119.8(2)8] is decreased as a result of electron
donation and withdrawal by the N3P3 ring. These values are
comparable to the mean value reported for N3P3Cl6 , viz.
Fig. 2. (a) An ORTEP-3 [26] drawing of compound (9) with the atom-
numbering scheme. Displacement ellipsoids are drawn at the 50%
probability level. (b) The conformation of the phosphazene ring in
compound (9).

90
D. Hakan et al. / Journal of Molecular Structure 753 (2005) 84–91
Table 4
˚
The bond lengths (A) and bond angles (8) with torsion angles (8) for (9)
Table 4 (continued)
N4–P3–N2–P2
N4–C7–C8–C9
N4–C7–C8–C13
N4–P3–N3–P1
O1–C13–C8–C9
O1–P3–N2–P2
O1–P3–N4–C6
O1–P3–N4–C7
O1–C13–C8–C7
O1–P3–N3–P1
P3–O1–C13–C12
P3–O1–C13–C8
P3–N4–C7–C8
P3–N4–C6–N5
P3–N4–C6–C2
K120.3(3)
K146.7(5)
34.8(6)
P1–N1
1.571(4)
1.564(3)
2.001(2)
1.991(2)
1.580(4)
1.569(3)
1.997(2)
2.000(2)
1.597(4)
1.589(4)
1.660(3)
1.586(3)
1.404(5)
1.417(5)
1.481(5)
1.502(6)
124.2(4)
121.0(3)
117.2(3)
119.6(3)
117.1(3)
119.5(4)
114.7(3)
100.5(9)
100.7(8)
108.3(2)
107.4(2)
108.4(2)
108.1(2)
109.4(2)
108.2(2)
120.3(2)
112.3(2)
110.9(2)
108.7(1)
119.3(2)
116.6(2)
113.9(2)
114.1(3)
122.9(6)
123.1(4)
112.5(4)
105.2(2)
106.6(2)
100.3(2)
119.8(2)
120.5(2)
121.8(2)
K145.1(4)
38.5(7)
P1–N3
P1–Cl1
118.2(3)
179.0(4)
131.6(2)
169.4(3)
K27.2(4)
K2.4(6)
K132.2(3)
129.9(4)
K50.8(5)
K15.4(6)
18.1(5)
P1–Cl2
P2–N1
P2–N2
P2–Cl3
P2–Cl4
P3–N2
P3–N3
P3–N4
P3–O1
O–C13
N4–C6
K158.3(4)
N4–C7
C7–C8
C2–C6–N4
C6–N4–C7
C6–N4–P3
C7–N4–P3
C8–C13–O1
C13–C8–C7
C13–O1–P3
Cl2–P1–Cl1
Cl3–P2–Cl4
N1–P1–Cl1
N1–P1–Cl2
N1–P2–Cl3
N1–P2–Cl4
N2–P2–Cl3
N2–P2–Cl4
N2–P2–N1
N2–P3–N4
N3–P1–Cl1
N3–P1–Cl2
N3–P1–N1
N3–P3–N2
N3–P3–N4
N4–C7–C8
N5–C5–C4
N5–C6–C2
N5–C6–N4
O1–P3–N2
O1–P3–N3
O1–P3–N4
P1–N1–P2
P2–N2–P3
P1–N3–P3
C7–N4–C6–N5
C7–N4–C6–C2
C12–C13–C8–C7
N1–P2–N2–P3
N1–P1–N3–P3
N2–P3–O1–C13
N2–P3–N4–C6
N2–P3–N4–C7
N2–P3–N3–P1
N2–P2–N1–P1
N3–P3–O1–C13
N3–P3–N2–P2
N3–P3–N4–C6
N3–P3–N4–C7
N3–P1–N1–P2
N4–P3–O1–C13
121.4(3)8 [37]. The C6–N4–C7 [121.0(3)8] and N4–C6–C2
[124.2(4)8] angles are expanded due to the steric interaction
between C1 and H7A [C1/H7a(C7) 2.757 A] atoms.
˚
Acknowledgements
The authors acknowledge Hacettepe University, Scien-
tific Research Unit (grant No. 02 02 602 002) and Anadolu
University, Commision of Scientific Research Projects
(grant No. 031032).
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