Microwave-assisted and conventional synthesis and stereogenic properties of monospirocyclotriphosphazene derivatives

Article abstract of DOI:10.1016/j.poly.2010.02.002

The reactions of hexachlorocyclotriphosphazene, N₃P₃Cl₆, with N/O donor type N-alkyl or (aryl)-o-hydroxybenzylamines HO(C₆H₄)CH₂NHR(Ar), [R(Ar) = C(CH₃)₃ (1), Ph (2)]

Full text of DOI:10.1016/j.poly.2010.02.002

Polyhedron 29 (2010) 1612–1618
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Microwave-assisted and conventional synthesis and stereogenic properties
of monospirocyclotriphosphazene derivatives
a
b
b
c
Muhammet Ißsıklan a, , Ömer Sonkaya , Bünyemin Çoßsut , Serkan Yeßsilot , Tuncer Hökelek
*
a Department of Chemistry, Faculty of Science and Art, Kırıkkale University, 71450 Yahßsihan-Kırıkkale, Turkey
b Department of Chemistry, Gebze Institute of Technology, Gebze 41400, Kocaeli, Turkey
c Department of Physics, Hacettepe University, 06800 Beytepe-Ankara, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
The reactions of hexachlorocyclotriphosphazene, N3P3Cl6, with N/O donor type N-alkyl or (aryl)-o-
hydroxybenzylamines HO(C6H4)CH2NHR(Ar), [R(Ar) = C(CH3)3 (1), Ph (2)] produce monospirocyclic tetra-
chlorocyclotriphosphazenes (1a and 2a). The geminal substituted cyclotriphosphazenes (1b, 1d, 2b and
2d) are obtained from the reactions of 1 equiv. of 1a and 2a with 2 equiv. of pyrrolidine or morpholine
in THF, while the fully substituted phosphazenes (1c, 1e, 2c and 2e) are formed from the reactions of 1a
and 2a with the excess pyrrolidine or morpholine in toluene, between 24 and 48 h. The microwave-
assisted reactions of 1a and 2a with excess pyrrolidine or morpholine in toluene afford the fully substi-
tuted products with higher yields than those which were obtained by conventional methods. The
structural investigations of the compounds have been verified by elemental analyses, ESI-MS, FTIR, 1H,
13C, 31P NMR and HETCOR techniques. The crystal structure of 2a is determined by X-ray crystallography
and the phosphazene ring is in the flattened boat form. Compounds 1b, 1d, 2b and 2d in which the spiro
aryloxy moiety provides the one centre of chirality exist as racemates and the chirality has been
confirmed by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA), (S)-(+)-2,2,2-tri-
fluoro-1-(90-anthryl)ethanol.
Received 23 December 2009
Accepted 1 February 2010
Available online 4 February 2010
Keywords:
Cyclophosphazene derivatives
Spiro-phosphazenes
Microwave-assisted synthesis
Chirality
Crystal structure
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
to conventional synthesis because of the advantages of direct
microwave heating, repeatability and controllability [13–15]. The
There are several studies in the literature on the reactions of
hexachlorocyclotriphosphazene, N3P3Cl6, with N/O donor type
difunctional reagents [1–3]. Reactions of difunctional reagents
with N3P3Cl6 may lead to a number of different types of phospha-
zene derivatives [4,5]. Only one of the two functional groups may
react with N3P3Cl6 to give open-chain products, and the dinucleo-
phile may replace two chlorine atoms on two different phospha-
zene rings to occur bridged phosphazene architecture. In
addition, spiro compounds can form if the difunctional ligand re-
acts with two geminal Cl atoms, and both functional groups of
the ligand may replace with two Cl atoms in a cis non-geminal
architecture to give trans annular substituted ansa derivatives.
On the other hand, the reagents may replace with two Cl atoms
on a number of different phosphazene rings to afford oligomers
or polymers. Many factors, such as solvent polarities, temperature,
size of the phosphazene ring and the properties of the difunctional
ligands play an important role in the formation of these derivatives
[6–8]. On the other hand, microwave-assisted reactions have at-
tracted great interest in organic syntheses [9–12] as an alternative
use of microwave irradiation for preparation of phosphazene
derivatives reduces reaction time and increases yield in compari-
son with conventional methods.
In this study, only the spiro products (1a and 2a) have been ob-
tained. We also reported here (i) the syntheses of geminal pyrroli-
dino (1b and 2b), and morpholino (1d and 2d), and fully
substituted spiro phosphazenes (1c, 1e, 2c and 2e); (ii) the stereo-
genic properties of the geminal compounds (1b, 1c, 2b and 2c)
investigated by 31P NMR measurements in the presence of CSA
[16–18].
2. Experimental
2.1. Materials
Hexachlorocyclotriphosphazene, N3P3Cl6 (Aldrich), purified by
fractional crystallization from n-hexane. Morpholine (Aldrich),
pyrrolidine (Fluka) and CSA (Aldrich), used without further purifi-
cation. All reactions have been monitored using TLC in different
solvents and chromatographed by using silica gel. 1H, 13C, and
31P NMR and HETCOR spectra were recorded on Bruker DPX FT-
NMR (500 MHz) spectrometer (SiMe4 as internal and 85% H3PO4
* Corresponding author. Tel.: +90 318 3574242; fax: +90 318 3572461.
E-mail address: misiklan@gmail.com (M. Isßıklan).
0277-5387/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2010.02.002

M. Ißsıklan et al. / Polyhedron 29 (2010) 1612–1618
1613
3
3
as external standards). The spectrometer was equipped with a
5 mm PABBO BB inverse gradient probe. Standard Bruker pulse
programs 1D WIN-NMR (release 6.0) and 2D WIN-NMR (release
6.1) were used in the experiment. Mass spectra were recorded on
a Bruker MicrOTOF LC-MS spectrometer using the electrospray ion-
isation (ESI) method; 35Cl values were used for calculated masses.
IR spectra were recorded on a Mattson 1000 FTIR spectrometer in
KBr discs. Microwave-assisted experiments have been performed
with a Milestone Start S system by using weflonTM magnet. Num-
bering of atoms in phosphazene derivatives are given in Scheme 1.
2H, JPH = 14.5 Hz, H1), 6.96–7.13 (m, 4H, JHH = 7.8 Hz, Ar–H).
13C{1H} NMR: (125 MHz, CDCl3, ppm): d 26.31 (d, JPC = 9.3 Hz,
3
3
NCH2CH2 pyrr.), 26.36 (d, JPC = 9.5 Hz, NCH2CH2 pyrr.), 29.82 (d,
3JPC = 3.5 Hz, C(CH3)3). 44.75 (d, JPC = 2 6Hz, C1), 45.95 (d,
2
2JPC = 4.3 Hz, NCH2 pyrr.), 46.25 (d, JPC = 5.1 Hz. NCH2 pyrr.),
2
2
3
56.10 (d, JPC = 3. Hz, NCH2), 117.91 (d, JPC = 6.1 Hz, C4), 123.54
(C6), 125.77 (C7), 128.65 (C5), 128.57 (d, JPC = 7.4 Hz, C2), d
151.16 (d, JPC = 8.9 Hz, C3).
3
2
2.2.3. 4,4,6,6-Tetrapyrrolidino-3-tert-butyl-3,4-dihydrospiro[1,3,2-
benzoxazaphosphorine][2k5,4k5,6k5] [1,3,5,2,4,6]triazatriphosphorine
(1c)
2.2. Preparation of compounds
Pyrrolidine (7.00 mL, 84.6 mmol) and triethylamine (10.0 mL)
N-tert-butyl-o-hydroxybenzylamine (1) and N-phenyl-o-
hydroxybenzylamine (2) have been prepared according to the
methods reported in the literature [19,20].
were added to
a stirred solution of compound 1a (1.00 g,
2.20 mmol) in dry toluene (100 mL) at room temperature. The mix-
ture was refluxed for 48 h, and the precipitated triethylaminehy-
drochloride was filtered off. The solvent was evaporated and the
product was purified by column chromatography with THF/Tolu-
ene (1:3). White powder was crystallized from acetonitrile. (THF,
Rf = 0.91). Yield; 0.82 g (63%) and mp: 161 °C. Anal. Calc. for
C27H47N8P3O; C, 54.71; H, 7.99; N, 18.90. Found: C, 54.75; H,
2.2.1. 4,4,6,6-Tetrachloro-3-tert-butyl-3,4-dihydro-spiro[1,3,2-
benzoxazaphosphorine][2k5,4k5,6k5] [1,3,5,2,4,6]triazatriphosphorine
(1a)
A solution of 1 (1.10 g, 5.75 mmol) in THF (50 mL) and triethyl-
amine (5.00 mL) were added to a stirred solution of N3P3Cl6 (2.00 g,
5.75 mmol) in THF (75 mL) at room temperature. The mixture was
stirred for 12 h, and the precipitated triethylamine hydrochloride
was filtered off. The solvent was evaporated and the product was
purified by column chromatography with toluene. White powder
was crystallized from n-hexane. (Toluene, Rf = 0.72). Yield; 1.46 g
(56%) and mp: 148 °C. Anal. Calc. for C11H15N4 P3OCl4; C, 29.10;
H, 3.32; N, 12.33. Found: C, 28.59; H, 3.08; N, 12.81%., m/z: 452
7.94; N, 18.91%., m/z: 592 (593 [M + H]+). FTIR (KBr, cmꢀ1):
m
3094;3074 (C–H arom.), 2966;2851 (C–H aliph.), 1193;169
(P@N). 1H NMR (500 MHz, CDCl3, ppm): d 1.66 (s, 9H, CH3), 1.79
(m, 16H, NCH2 pyrr.), 3.13 and 3.23 (m, 16H, NCH2CH2 pyrr.),
3
3
4.18 (d, 2H, JPH = 15.8 Hz, H1), 6.90–7.21 (m, 4H, JHH = 8.7 Hz,
Ar–H). 13C{1H} NMR: (125 MHz, CDCl3, ppm):
d 26.40 (d,
3JPC = 7.9 Hz, NCH2CH2 pyrr.), 29.16 (d, JPC = 3.4 Hz, CH3), 44.86
3
2
2
(d, JPC = 2.0 Hz, C1), 45.99 and 46.25 (d, JPC = 2.3 Hz, NCH2 pyrr.),
55.23 (d, JPC = 3.4 Hz, NCH2), 117.57 (d, JPC = 5.8 Hz, C4), 122. 29
(C6), 125.74 (C7), 129.14 (C5), 129.14 (d, JPC = 6.2 Hz, C2), d
152.40 (d, JPC = 9.0 Hz, C3).
(453 [M + H]+). FTIR (KBr, cmꢀ1):
m 3094; 3074 (C–H arom.),
2
3
2972; 2855 (C–H aliph.), 1245; 1176 (P@N), 579; 483 (P–Cl). 1H
NMR (500 MHz, CDCl3, ppm): d 1.47 (s, 9H, CH3), 4.25 (d, 2H,
3JPH = 16.5 Hz, H1), 7.12–7.19 (m, 4H, Ar–H). 13C{1H} NMR: (125
3
2
3
MHz, CDCl3, ppm): d 28.84 (d, JPC = 3.8 Hz, CH3), 45.00 (d,
2
2JPC = 2.5 Hz, C1), 57.35 (d, JPC = 3.8 Hz, C(CH3)3), 118.38 (d,
2.2.4. Microwave-assisted synthesis of 1c
3JPC = 6.3 Hz, C4), 124.86 (C6), 126.14 (C7),128.15 (d, JPC = 6.3 Hz,
3
Pyrrolidine (7.00 mL, 84.6 mmol) and triethylamine (10.0 mL)
2
were added to
a stirred solution of compound 1a (1.00 g,
C2), 129.54 (C5), 150.34 (d, JPC = 8.8 Hz, C3).
2.20 mmol) in dry toluene (100 mL). The mixture was refluxed
for 0.25 h, and triethylaminehydrochloride was filtered off. Tolu-
ene was evaporated and the crude product was purified by column
chromatography with THF/Toluene (1:3), yield; 1.14 g (88%).
2.2.2. 6,6-Dichloro-4,4-di(pyrrolidino)-3-tert-butyl-3,4-dihydro-
spiro[1,3,2-benzoxazaphosphorine][2k5,4k5,6k5]
[1,3,5,2,4,6]triazatriphosphorine (1b)
Pyrrolidine (0.36 mL, 4.40 mmol) and triethylamine (5.00 mL)
were added to
a stirred solution of compound 1a (1.00 g,
2.2.5. 6,6-Dichloro-4,4-di(morpholino)-3-tert-butyl-3,4-
dihydrospiro[1,3,2-benzoxazaphosphorine][2k5,4k5,6k5]
[1,3,5,2,4,6]triazatriphosphorine (1d)
2.20 mmol) in THF (100 mL) at room temperature. The mixture
was refluxed for 12 h, and the precipitated triethylamine hydro-
chloride was filtered off. The solvent was evaporated and the prod-
uct was purified by column chromatography with THF/Toluene
(1:3). White powder was crystallized from n-heptane. (Toluene,
Rf = 0.27). Yield; 0.75 g (65%) and mp: 159 °C. Anal. Calc. for
C19H31N6 P3OCl2; C, 43.60; H, 5.97; N, 16.06. Found: C, 43.63; H,
Morpholine (0.38 mL, 4.36 mmol) and triethylamine (5.00 mL)
were added to
a stirred solution of compound 1a (1.00 g,
2.20 mmol) in dry toluene (100 mL) at room temperature. The mix-
ture was refluxed for 24 h, and the precipitated triethylaminehy-
drochloride was filtered off. The solvent was evaporated and the
product was purified by column chromatography with THF/Tolu-
ene (1:3). White powder was crystallized from n-hexane. (THF/Tol-
uene (1:3), Rf = 0.40). Yield; 0.74 g (60%) and mp: 185 °C. Anal. Calc.
for C19H31N6P3O3Cl2; C, 41.09; H, 5.63; N, 15.13. Found: C, 41.28; H,
5.93; N, 16.06%., m/z: 422 (423 [M + H]+). FTIR (KBr, cmꢀ1):
m
3094;3074 (C–H arom.), 2963;2865 (C–H aliph.), 1234;1169
(P@N), 584;480 (P–Cl). 1H NMR (500 MHz, CDCl3, ppm): d 1.36 (s,
9H, C(CH3)3), 1.81 (m, 4H, NCH2CH2 pyrr.), 1.87 (m, 4H, NCH2CH2
pyrr.), 3.14 (m, 4H, NCH2 pyrr.), 3.22 (m, 4H, NCH2 pyrr.), 4.19 (d,
5.39; N, 14.99%., m/z: 554 (555 [M + H]+). FTIR (KBr, cmꢀ1):
m
3094;3074 (C–H arom.), 2966;2851 (C–H aliph.), 1248;1170
(P@N), 553;489 (P–Cl). 1H NMR (500 MHz, CDCl3, ppm): d 1.47(s,
9H, CH3), 3.18 and 3.23 (m, 8H, NCH2 morp.), 3.66 and 3.76 (m,
Cl
Cl
4
5
9
10
P
N
3
8
8H, NCH2CH2 morp.), 4.22 (d, 2H, JPH = 16.2 Hz, H1), 6.85–7.20
N
P
N
P
6
O
R:
11
Cl
Cl
3
(m, 4H, JHH = 8.7 Hz, Ar–H). 13C{1H} NMR: (125 MHz, CDCl3,
3
2
ppm): d 29.15 (3JPC = 3.4 Hz, CH3), 45.07 (d, JPC = 2.6 Hz, C1),
7
2
2
N
R
56.68 (d, JPC = 3.6 Hz, C(CH3)3), 44.67 and 44.89 (NCH2 morp.),
1
2
67.22 and 67.27 (d, JPC = 6.6 Hz, NCH2CH2 morp.), 117.94 (d,
3
3JPC = 6.2 Hz, C4), 124.20 (C6), 126.21 (C7), 128.40 (d, JPC = 6.2 Hz,
2
Scheme 1. Numbering of atoms in phosphazene derivatives.
C2), 129.14 (C5), 151.02 (d, JPC = 9.0 Hz, C3).

1614
M. Ißsıklan et al. / Polyhedron 29 (2010) 1612–1618
2.2.6. 4,4,6,6-Tetramorpholino-3-tert-butyl-3,4-dihydrospiro[1,3,2-
benzoxazaphosphorine][2k5,4k5,6k5] [1,3,5,2,4,6]triazatriphosphorine
(1e)
2.2.10. 4,4,6,6-Tetrapyrrolidino-3-phenyl-3,4-dihydrospiro[1,3,2-
benzoxazaphosphorine][2k5,4k5,6k5] [1,3,5,2,4,6]triazatriphosphorine
(2c)
Morpholine (1.14 mL, 12.7 mmol) and triethylamine (10.0 mL)
The workup procedure was similar to that of compound 1c,
using pyrrolidine (7.00 mL, 84.6 mmol) and 2a (1.00 g, 2.11 mmol).
(THF/Toluene; 1:3, Rf = 0.44). Yield; 0.45 g (31%) and mp: 210 °C.
Anal. Calc. for C29H43N8P3O3; C, 56.89; H, 7.02; N, 18.29. Found:
C, 57.06; H, 6.91; N, 18.24%., m/z: 612 (613 [M + H]+). FTIR (KBr,
were added to
a stirred solution of compound 1a (1.00 g,
2.20 mmol) in dry toluene (100 mL) at room temperature. The mix-
ture was refluxed for 48 h, and the precipitated triethylaminehy-
drochloride was filtered off. The solvent was evaporated and the
product was purified by column chromatography with THF/Tolu-
ene (1:3). White powder was crystallized from acetonitrile. (THF,
Rf = 0.91). Yield; 0.47 g (30%) and mp: 219 °C. Anal. Calc. for
C27H47N8P3O5; C, 49.38; H, 7.21; N, 17.06. Found: C, 50.00; H,
cmꢀ1):
m 3087;3067 (C–H arom.), 2946;2860 (C–H aliph.),
1199;1172 (P@N). 1H NMR: (500 MHz, CDCl3, ppm): d 3.20 (m,
3
4H, NCH2 pyrr.), 3.79 (m, 4H, JHH = 7.5 Hz, NCH2CH2 pyrr.), 4.74
3
3
(m, 2H, JPH = 14. Hz, JHH = 7.5 Hz, H1), 7.15–7.44 (m, 4H, Ar–H).
6.71; N, 16.56%., m/z: 656 (657 [M + H]+). FTIR (KBr, cmꢀ1):
m
13C{1H} NMR: (125 MHz, CDCl3, ppm): d 44.16 (NCH2 pyrr.),
52.39 (d, JPC = 2.5 Hz, C1), 66.42 (d, JPC = 10.4 Hz NCH2CH2 pyrr.),
118.92 (d, JPC = 8.1 Hz, C4), 124.49 (C11), 125.24 (d, JPC = 5.7 Hz,
C6) 126.63 (C5), 126.66 (d, JPC = 7.2 Hz, C9), 126.71 (C7), 129.28
2
3
3094;3074 (C–H arom.), 2975;2847 (C–H aliph.), 1246;1180
(P@N). 1H NMR: (500 MHz, CDCl3, ppm): d 1.49 (s, 9H, CH3), 3.16
3
3
3
3
and 3.65 (m, 16H, NCH2CH2 morp.), 4.19 (d, 2H, JPH = 15.5 Hz,
H1), 6.84–7.20 (m, 4H, Ar–H). 13C{1H} NMR: (125 MHz, CDCl3,
(C4), 129.64 (C10), 142.08 (d, JPC = 2.6 Hz, C8), 150.62 (d,
2
ppm): d 29.46 (d, 3JPC = 3.3 Hz, CH3), 44.92 and 44.86 (NCH2 morp.),
2JPC = 8.3 Hz, C3).
2
2
45.03 (d, JPC = 2.4 Hz, C1), 55.85 (C(CH3)3), 67.50 (d, JPC = 4.3 Hz,
3
NCH2CH2 morp.), 117.61 (d, JPC = 5.8 Hz, C4), 123.27 (C6), 126.26
2.2.11. Microwave-assisted synthesis of compound 2c
Pyrrolidine (7.00 mL, 84.6 mmol) and triethylamine (10.0 mL)
were added to a stirred solution of compound 2a (1.00 g,
3
(C7), 128.60 (d, JPC = 6.4 Hz, C2), 129.26 (C5), 151.96 (d,
2JPC = 9.3 Hz, C3).
2.11 mmol) in dry toluene (100 mL). The mixture was refluxed
for 15 min and triethylaminehydrochloride was filtered off. Tolu-
ene was evaporated and the crude product was purified by column
chromatography with THF/Toluene (1:3), yield; 1.25 g (97%).
2.2.7. Microwave-assisted synthesis of 1e
Morpholine (1.14 mL, 12.72 mmol) and triethylamine
(10.00 mL) were added to a stirred solution of compound 1a
(1.00 g, 2.20 mmol) in dry toluene (100 mL). The mixture was re-
fluxed for 2 h., and triethylaminehydrochloride was filtered off.
Toluene was evaporated and the crude product was purified by col-
umn chromatography with THF/Toluene (1:3), yield; 1.37 g (87%).
2.2.12. 6,6-Dichloro-4,4-di(morpholino)-3-phenyl–3,4-dihydro-
spiro[1,3,2-benzoxazaphosphorine][2k5,4k5,6k5]
[1,3,5,2,4,6]triazatriphosphorine (2d)
The workup procedure was similar to that of compound 1d,
using morpholine (0.38 mL, 4.36 mmol) and 2a (1.18 g,
2.50 mmol). Rf = 0.54 (THF/Toluene; 1:3). Yield; 0.25 g (19%) and
mp: 178 °C. Anal. Calc. for C21H27N6P3O3Cl2; C, 43.83; H, 4.73; N,
14.61. Found: C, 44.02; H, 4.72; N, 15.30%., m/z: 574 (575
2.2.8. 4,4,6,6-Tetrachloro-3-phenyl-3,4-dihydrospiro[1,3,2-
benzoxazaphosphorine][2k5,4k5,6k5] [1,3,5,2,4,6]triazatriphosphorine
(2a)
The workup procedure was similar to that of compound 1a,
using 2 (1.15 g, 5.75 mmol) and N3P3Cl6 (2.00 g, 5.75 mmol). (Tol-
uene, Rf = 0.68). Yield; 0.65 g (24%) and mp: 118 °C. Anal. Calc. for
C13H11N4 P3OCl4; C, 32.92; H, 2.34; N, 11.82. Found: C, 32.56; H,
[M + H]+). FTIR (KBr, cmꢀ1):
m 3090;3074 (C–H arom.), 2946;2860
(C–H aliph.), 1199;1172 (P@N), 566;485 (P–Cl). 1H NMR:
(500 MHz, CDCl3, ppm): d 2.60–3.19 (m, 8H, NCH2 morp.), 3.60
3
2.40; N, 11.60%., m/z: 472 (473 [M + H]+). FTIR (KBr, cmꢀ1):
m
and 3.74 (m, 8H, NCH2CH2 morp.), 4.70 (d, 2H, JPH = 14. Hz, H1),
3088;3045 (C–H arom.), 2976;2845 (C–H aliph.), 1260;1185
7.01–7.47 (m, 9H, Ar–H). 13C{1H} NMR: (125 MHz, CDCl3, ppm): d
3
(P@N), 578;519 (P–Cl). 1H NMR (500 MHz, CDCl3, ppm): d 4.72
43.98 and 44.72 (NCH2 morp.), 52.92 (C1), 67.14 (d, JPC = 4.9 Hz,
3
3
(d, 2H, JPH = 15.0 Hz, H1), 7.23–7.85 (9H, Ar–H), 13C{1H} NMR:
NCH2CH2 morp.), 118.91 (d, JPC = 7.3 Hz, C4), 124.44 (C9), 125.54
2
3
(125 MHz, CDCl3, ppm): d 52.46 (d, JPC = 2.5 Hz, C1), 119.10 (d,
(C11), 125.76 (d, JPC = 3.5 Hz, C2), 126.63 (C6), 127.14 (C7), 128.47
3
2
3JPC = 8.8 Hz, C4), 124.70 (d, JPC = 7.4 Hz, C2), 124.80 (d,
(C5) 129.28 C10), 143.26 (C8), 150.90 (d, JPC = 8.9 Hz, C3).
3JPC = 6.30 Hz, C9), 126.71 (C11), 127.04 (C6), 127.50 (C7), 129.52
2
(C5), 129.85 (C10), 141.31 (d, JPC = 2.5 Hz, C8), 150.25 (d,
2.2.13. 4,4,6,6-Tetramorpholino-3-phenyl-3,4-dihydro-spiro[1,3,2-
benzoxazaphosphorine][2k5,4k5,6k5] [1,3,5,2,4,6]triazatriphosphorine
(2e)
2JPC = 7.5 Hz, C3).
2.2.9. 6,6-Dichloro-4,4-di(pyrrolidino)-3-phenyl-3,4-
The workup procedure was similar to that of compound 1e,
using morpholine (1.14 mL, 12.72 mmol) and 2a (1.00 g,
2.11 mmol). Rf = 0.58 (THF/Toluene; 1:2). Yield; 1.01 g (71%) and
mp: 217 °C. Anal. Calc. for C29H43N8P3O5; C, 51.47; H, 6.40; N,
16.56. Found: C, 51.33; H, 6.34; N, 16.82%., m/z: 676 (677
dihydrospiro[1,3,2-benzoxazaphosphorine][2k5,4k5,6k5]
[1,3,5,2,4,6]triazatriphosphorine (2b)
The workup procedure was similar to that of compound 1b,
using pyrrolidine (0.58 mL, 3.50 mmol) and 2a (1.65 g, 3.50 mmol).
(Toluene, Rf = 0.34). Yield; 0.38 g (20%) and mp: 158 °C. Anal. Calc.
for C21H27N6 P3OCl2; C, 46.41; H, 5.01; N, 15.47. Found: C, 45.94; H,
[M + H]+). FTIR (KBr, cmꢀ1):
m 3093;3070 (C–H arom.), 2958;2846
(C–H aliph.), 1204;1174 (P@N). 1H NMR: (500 MHz, CDCl3, ppm):
d 2.58–3.18 (m, 16H, NCH2 morp.), 3.50 and 3.67 (m, 16H,
4.76; N, 15.61%., m/z: 542 (543 [M + H]+). FTIR (KBr, cmꢀ1):
m
3
3081;3019 (C–H arom.), 2974;2869 (C–H aliph.), 1243;1172
(P@N), 576;517 (P–Cl). 1H NMR: (500 MHz, CDCl3, ppm): d 1.61
and 1.88 (m, 8H, NCH2CH2 pyrr.). 3.14 and 3.22 (m, 8H, NCH2
NCH2CH2 morp.), 4.68 (d, 2H, JPH = 14.0 Hz, H1), 6.96–7.48 (m,
9H, Ar–H). 13C{1H} NMR: (125 MHz, CDCl3, ppm): d 43.88 and
3
44.15 (NCH2 morp.), 51.78 (C1), 66.67 (d, JPC = 4.7 Hz, NCH2CH2
3
3
pyrr.), 4.83 (d, 2H, JPH = 14.6 Hz, H1), 7.10–7.48 (m, 9H, Ar–H).
morp.), 117.82 (d, JPC = 7.1 Hz, C4), 122.72 (C9), 124.68 (C11),
13C{1H} NMR: (125 MHz, CDCl3, ppm): d 24.19 and 24.37 (d,
125.12 (d, JPC = 3.4 Hz, C2), 125.37 (C6), 125.94 (C7), 128.10 (C5)
3
3JPC = 9.4 Hz, NCH2CH2 pyrr.), 43.66 and 44.11 (d, JPC = 4.4 Hz,
128.36 (C10), 143.99 (C8), 150.78 (d, JPC = 8.7 Hz, C3).
2
2
2
3
NCH2 pyrr.), 50.50 (d, JPC = 2.1 Hz, C1), 116.82 (d, JPC = 7.9 Hz,
3
C4), 121.66 (C11), 123.12 (d, JPC = 5.7 Hz, C2), 124.13 (d,
2.2.14. Microwave-assisted synthesis of compound 2e
Morpholine (1.14 mL, 12.72 mmol) and triethylamine (10.0 mL)
were added to a stirred solution of compound 2a (1.00 g,
3JPC = 3.6 Hz, C9), 124.80 (C7), 126.79 (C5), 127.13 (C10), 141.43
2
(C8), 148.98 (d, JPC = 8.5 Hz, C3).

M. Ißsıklan et al. / Polyhedron 29 (2010) 1612–1618
1615
Table 1
Crystallographic data for 2a.
3. Results and discussion
3.1. Synthesis
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C13H11N4P3OCl4
473.97
triclinic
The monospirocyclic tetrachlorocyclotriphosphazenes (1a and
2a; Scheme 2) have been obtained from the reactions of N/O do-
nor-type-N-alkyl (or aryl)-o-hydroxybenzylamines (1 and 2) in
THF. Compounds 1a and 2a have four reactive chlorine atoms
which can be substituted quite readily with amines. Utilising these
features the geminal pyrrolidino (1b and 2b) and morpholino
phosphazenes (1d and 2d) have been synthesized by the reactions
of 1 equiv. of 1a and 2a with 2 equiv. of pyrrolidine and morpho-
line, respectively, in the presence of Et3N in refluxing THF. In addi-
tion, the fully substituted phosphazenes (1c and 2c) and (1e and
2e) have been obtained from the reactions of 1a and 2a with the
excess pyrrolidine and morpholine in toluene, respectively
(Scheme 2). According to the conventional method monospirocy-
clic derivatives (1a and 2a) and geminal alkylamino spirocyclotri-
phosphazenes (1b, 1d, 2b and 2d) have been synthesized with
the yields in a range of 45–65%. The fully substituted (1c, 1e, 2c
and 2e) derivatives have been obtained with the yields in a range
of 30–71%, whilst the yields of microwave assisted reactions are
very high (85–97%). The use of microwave is very helpful to im-
prove the yields and to decrease the reaction time. As expected,
in the microwave assisted synthesis of 1c and 1e which contain
bulky substituents bonded to nitrogen atom of spiro-ring, the reac-
tion time is longer than that of 2c and 2e.
ꢀ
P1
8.868(8)
10.765(5)
11.823(6)
68.28(4)
69.68(5)
68.91(5)
948.0(11)
2
0.888
1.660
12193
11745
0.0934
40.00
0.806/0.878
227
0.0781
0.2835
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
l
q
(Mo K
a
) (cmꢀ1
)
(calcd)(g cmꢀ1
)
Number of reflections total
Number of reflections unique
Rint
2hmax (°)
Tmin/Tmax
Number of parameters
R [F2 > 2
r
(F2)]
wR
2.11 mmol) in dry toluene (100 mL).The mixture was refluxed for
0.5 h, and triethylaminehydrochloride was filtered off. Toluene
was evaporated and the crude product was purified by column
chromatography with THF/Toluene (1:2), yield; 1.21 g (85%).
2.3. X-ray crystallography
The microanalyses, FTIR, MS and NMR data are consistent with
the proposed structures of the compounds. All of the new phospha-
zene derivatives show the protonated molecular ion (M + H+)
peaks.
Colourless crystals of 2a were grown from n-heptane at room
temperature. Crystallographic data are listed in Table 1 and se-
lected bond lengths and angles are given in Table 3. Crystallo-
graphic data were collected on a Rigaku AFC7S diffractometer
using Mo Ka radiation (k = 0.71073 Å) at T = 294 K. Absorption cor-
3.2. FTIR and NMR spectroscopy
rection by psi-scan [21] was applied. Structure was solved by di-
rect methods [22] and refined by full-matrix least squares
against F2 using all data [22]. All non-H atoms were refined aniso-
tropically. The H atom positions were calculated geometrically at
distances of 0.93 (CH) and 0.97 (CH2) Å from the parent atoms; a
riding model was used during the refinement process and the
Uiso(H) values were constrained to be 1.2 Ueq(carrier atom).
The asymmetric and symmetric stretching absorptions of the
Ar–H protons are observed at the ranges of 3075–3052 cmꢀ1 and
3040–3024 cmꢀ1, respectively. The FTIR spectra of all the phosp-
hazenes exhibit strong stretching bands between 1240 and
1170 cmꢀ1 attributed to mP@N bonds of the phosphazene ring
[23,24]. In addition, the asymmetric and symmetric absorption
Table 2
31P NMR parameters of compounds and the effect of CSA on 31P NMR chemical shifts.a
Compound
Spin system
>PX2
1
>PCl2
2
>P(ORN)
3
X or X2
2J(PP)/Hz
1,2
1,3
2,3
(i) 31P NMR chemical shifts (ppm) and geminal PNP coupling constants (Hz)
1a
2a
1b
2b
1c
2c
1d
2d
1e
2e
AX2
AX2
AMX
AMX
AX2
23.39
24.73
25.49
25.71
5.59
3.80
Cl
Cl
54.6
56.6
57.8
58.9
-
14.86
17.16
18.13
19.61
17.83
19.33
23.04
22.13
10.07
8.19
16.66
14.95
10.67
8.02
C4H8N
C4H8N
C4H8N
C4H8N
C4H8NO
C4H8NO
C4H8NO
C4H8NO
48.5
45.0
49.6
51.1
47.2
48.9
48.5
52.3
47.5
50.5
AX2
-
AMX
AMX
AX2
25.30
25.72
55.2
49.3
55.9
57.2
16.44
13.60
AX2
(ii) Change in chemical shifts (ppb) at CSA:compound mole ratio of 30:1
1b
2b
1d
2d
ꢀ4.0
291.7
144.5
116.5
150
151.5
73
C4H8N
C4H8N
C4H8NO
C4H8NO
46.9
43.7
58.3
48.7
47.6
51.9
58.5
50.8
56.8
57.5
55.0
56.5
45
ꢀ108
ꢀ190
ꢀ4.5
ꢀ4.2
(iii) Separation of signals of enantiomers (ppb) at CSA:compound mole ratio of 30:1
1b
2b
1d
2d
212
38
70
141
149
55
95
28
25
C4H8N
C4H8N
C4H8NO
C4H8NO
80
200
a
202.38 MHz 31P NMR measurements in CDCl3 solutions at 298 K.

1616
M. Ißsıklan et al. / Polyhedron 29 (2010) 1612–1618
Table 3
The selected bond lengths (Å) and angles with the selected torsion angles (°) for 2a.
P1–N1
P2–N2
P1–N4
1.600(3)
1.585(3)
1.637(3)
P1–N3
P3–N2
P1–O1
1.583(3)
1.576(3)
1.581(2)
P2–N1
P3–N3
1.563(3)
1.569(3)
N1–P1–N3
P1–N1–P2
N3–P1–N4
N1–P1–O1
P1–N4–C8
115.28(15)
122.90(17)
110.81(16)
107.51(17)
117.10(19)
N1–P2–N2
P2–N2–P3
N3–P1–O1
O1–P1–N4
C7–N4–C8
119.23(16)
119.34(18)
107.01(15)
102.97(13)
115.5(2)
N2–P3–N3
P1–N3–P3
N1–P1–N4
P1–N4–C7
119.73(15)
122.57(18)
112.30(15)
118.5(3)
N3–P1–N1–P2
N4–P1–N1–P2
6.6(3)
ꢀ121.6(2)
O1–P1–N3–P3
N1–P1–N3–P3
ꢀ130.3(2)
ꢀ10.8(3)
N2–P2–N1–P1
N2–P3–N3–P1
1.7(3)
6.6(3)
Cl
Cl
P
N
P
N
P
Cl
Cl
Cl
Cl
N
R
X
Comp.
R
X
Comp.
1c
But
C4H8NO 1b
But
C4H8N
But
Ph
Ph
C4H8NO 1d
C4H8NO 2b
C4H8NO 2d
But
Ph
Ph
C4H8NO 1e
C4H8N 2c
C4H8NO 2e
CH2NHR
OH
THF/Et3N
X
N
X
Cl
Cl
Cl
Cl
P
N
P
pyrr./morp.
pyrr./morp.
THF/ Et3N
P
N
P
O
N
P
N
P
O
X
Cl
Cl
N
P
N
P
O
X
X
P
Toluene/ Et3N
N
X
N
R
N
N
R
N
R
R
Comp.
But
Ph
1a
2a
Scheme 2. The chloride replacement reaction pathway of N3P3Cl6 with the nucleophiles.
Fig. 1. 31P NMR spectra of 2b (a) in CDCl3, (b) expansion of signals showing AMX spin system, (c) addition of CSA at ca. 30:1 mol ratio shows the doubling of signals which is
characteristic for a racemate.
bands of mPCl2 have arisen for the tetrachloro (1a and 2a) and di-
chloro (1b, 1d, 2b and 2d) phosphazenes in the ranges of 584–
553 cmꢀ1 and 519–480 cmꢀ1, respectively.
As an example, the proton-decoupled 31P NMR spectrum of com-
pound 2b is shown as the expected AMX spin system in Fig. 1a. Sig-
nal assignment of the representative compound 2b is
straightforward with the quartet at ca 25.71 ppm belonging to
>PCl2, the quartet at ca. 17.16 ppm to >P(Pyrr)2 and the quartet
at ca. 8.19 ppm to >P(ORN) (Table 2). Fig. 2 illustrates the spatial
view of the architectures for better understanding. Compounds
The 1H-decoupled 31P NMR data of the phosphazenes are given
in Table 2. The data indicated that all of the phosphazenes have
spiro structures. The spin systems are interpreted as AX2 for 1a,
1c, 1e, 2a, 2c and 2e and AMX for 1b, 1d, 2b, and 2d (Table 2).

M. Ißsıklan et al. / Polyhedron 29 (2010) 1612–1618
1617
1a, 1c, 1e, 2a, 2c and 2e show a typical five lines resonance pattern
consisting of a triplet for one P (spiro) atom and a doublet for two
other P atoms. The geminal phosphazenes, 1b, 1d, 2b and 2d show
a 12-lines resonance pattern consisting of a doublet of doublets for
all of the P atoms. The coupling constants of all the compounds are
between 45.0 and 58.9 Hz. Compounds 1a, 1c, 1e, 2a, 2c and 2e
have the planes of symmetry, whereas compounds 1b, 1d, 2b
and 2d in which the spiro aryloxy moiety provides the one centre
of chirality are asymmetrical. As expected, these compounds con-
taining one stereogenic centre exist as racemates and their enanti-
omers have been analysed by changes in the 31P NMR spectra on
addition of a chiral solvating agent, (S)-(+)-2,2,2-trifluoro-1-(90-
anthryl)ethanol, (CSA) [6,25–27]. On titration with CSA, the chem-
ical shifts change as a result of the equilibrium between the com-
pound and its ligand-complexed form and the changes (in ppb) at a
mole ratio of CSA:compound of 30:1 are summarised in Table 2. In
general, there are changes in both 31P NMR chemical shifts (ex-
pressed in ppb) and magnitudes of geminal 2J(PP) coupling con-
stants. On titration with CSA, some of the signals in each of the
compounds 1b, 1d, 2b and 2d separate into two signals of equal
intensity corresponding to the different effects on the two enanti-
omers. These results confirmed that cyclotriphosphazene deriva-
tives containing one stereogenic centre exist as racemates. The
spectra of 2b are depicted in Fig. 1 for comparison. Addition of
CSA at a 30:1 molar ratio causes the separations of all signals into
two lines of equal intensity indicating that 2b exists as a racemate.
The separations in chemical shifts (in ppb) of enantiomers are gi-
ven separately in Table 2 for compounds 1b, 1d, 2b and 2d.
The 1H and 13C{1H} NMR signals have been assigned on the ba-
sis of chemical shifts, multiplicities and coupling constants using
the data of 1H, 13C{1H} NMR and HETCOR spectra for the phospha-
zene derivatives. The protons of the benzylic moieties, Ar–CH2N
give rise to doublets and the multiplets for 1a, 1c, 1d, 1e, 2a, 2c,
2e and 1b, 2b, 2d, respectively. The geminal Ar–CH2N protons of
1b, 2b and 2d are not equivalent to each other; therefore, they give
two groups of multiplets with small separations. The 3JPH values of
Ar–CH2N protons are between 14.0 and 16.2 Hz. The signals of
methyl protons of 1a, 1b, 1c, 1d and 1e are observed as singlets
in the range of 1.36–1.66 ppm. In the 1H NMR spectra of geminal
X
R
O
N
R
N
N
But or Ph
X
X
But or Ph
O
Cl
Cl
Fig. 2. Spatial view of 1b, 1d, 2b and 2d.
Fig. 3. (a) An ORTEP-3 [33] drawing of 2a with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level, (b) the conformation of the
phosphazene ring, and (c) the conformation of the six-membered spiro-ring.

1618
M. Ißsıklan et al. / Polyhedron 29 (2010) 1612–1618
phosphazenes 1b, 1d, 2b and 2d; the two pyrrolidino or morpho-
lino substituents bonded to the same P atom show two groups of
NCH2 signals with small separations. As expected, the same situa-
tion is observed for NCH2CH2 protons. All of the expected carbon
signals are interpreted from the 13C{1H} NMR spectra of the phosp-
hazenes. The NCH2 signals of 1b, 1c, 1d, 1e, 2b, 2c, 2d and 2e are
confirmed by HETCOR experiments; for NCH2 (pyrr.) and Ar–CH2.
The expected coupling constants between aromatic C atoms and
P atoms are observed for C1, C2, C3 and C4 as doublets (see experi-
mental part). In the 13C{1H} NMR spectra of geminal phosphazenes
1b, 1d, 2b and 2d, the two pyrrolidino or morpholino substituents
bonded to the same P atom show two groups of NCH2CH2 carbons
indicating different environments (Fig. 2).
microwave, compared with those from the conventional methods.
The use of microwave is really helpful to improve the yields and re-
duce the reaction times. The enantiomers of geminal monospirocy-
clotriphosphazenes have been determined by the changes in the
31P NMR spectra on addition of a Chiral Solvating Agent (CSA),
(S)-(+)-2,2,2-trifluoro-1-(90-anthryl)ethanol. These results con-
firmed that geminal monospirocyclotriphosphazenes containing
one centre of chirality exist as racemates. The fully substituted
cyclotriphosphazene derivatives may also be ligating agents for
some transition metal cations.
5. Supplementary data
CCDC 758922 contains the supplementary crystallographic data
for 2a. These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html.
3.3. X-ray structure of 2a
The solid state structure of compound 2a confirms the assign-
ments of its structure from spectroscopic data. The molecular
structure of 2a along with the atom-numbering scheme is depicted
in Fig. 3a. The phosphazene ring of 2a is not planar and is in flat-
tened boat form [Fig. 3b; u2 = 152.5(1.3)° and h2 = 102.1(1.3)°] hav-
ing total puckering amplitude [28] QT of 0.107(3) Å. The N atoms
are displaced above (+) and below (ꢀ) the least squares plane
through the P atoms by the following distances: N1 ꢀ 0.022(3),
N2 0.088(4) and N3 ꢀ 0.118(3) Å. As expected in 2a, six-membered
spiro-ring is in nearly twisted form [Fig. 3c; u2 = 55.8(2)° and
h2 = 111.8(2)°] having total puckering amplitude [28] QT of
0.193(11) Å. The sum of the bond angles around the atom N4
[351.1(2)°] shows the change in hybridization of the atom slightly
from trigonal planar towards pyramidal. The pyramidality of N4
atom especially may depend on the conformations of phosphazene
and spiro-rings (Fig. 3b and c).
In the phosphazene ring, the endocyclic P–N bonds are in the
range of 1.563(3)–1.600(3) Å and has an average value of
1.579(3) Å, which is shorter than the exocyclic P–N bond of
1.637(3) Å (Table 3). The phosphazene ring P–N bonds show dou-
ble-bond character. In addition, exocyclic P–N bond is at the lower
limit of the single-bond length. In phosphazenes, the PN single and
double-bonds are estimated to be in the ranges of 1.628–1.691 and
1.571–1.604 Å, respectively [29]. Recently, multiple-bond charac-
ter of the PN bonds in the phosphazene ring are attributed to the
presence of negative hyperconjugation [30,31]. As can be seen
Acknowledgements
The authors acknowledge the ‘‘Scientific and Technical Research
_
Council of Turkey; TÜBITAK” (Grant No. 106T503). T.H. is indebted
to ‘‘Hacettepe University, Scientific Researchs Unit” Grant No. 02
02 602 002 for financial support.
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N/O donor type ligands which are N-tert-butyl-o-hydroxyben-
zylamine (1) and N-phenyl-o-hydroxybenzylamine (2) have led
to the formation of monospirocyclotriphosphazene (1a and 2a)
architectures via the condensation reactions of N3P3Cl6. The substi-
tution reactions of monospirocyclotriphosphazene derivatives
with the pyrrolidine or morpholine produce the geminal (1b, 1d,
2b and 2d) and fully substituted (1c, 1e, 2c and 2e) derivatives.
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