Synthesis and characterization of cyclotriphosphazenes bearing chalcones derivatives

Article abstract of DOI:10.1080/10426500902893217

A series of new cyclotriphosphazenes bearing chalcones derivatives, N ₃P₃Cl₅[OC₆H₄ CH=CHC(O)C₆H₄OCnH_2n+1] and N₃P ₃[OC₆H₄CH

Full text of DOI:10.1080/10426500902893217

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Phosphorus, Sulfur, and Silicon and the
Related Elements
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Synthesis and Characterization of
Cyclotriphosphazenes Bearing Chalcones
Derivatives
Zainab Ngaini a & Norashikin I. Abdul Rahman a
a Department of Chemistry, Faculty of Resource Science and
Technology , Universiti Malaysia Sarawak , Kota Samarahan,
Sarawak, Malaysia
Published online: 24 Feb 2010.
To cite this article: Zainab Ngaini & Norashikin I. Abdul Rahman (2010) Synthesis and Characterization
of Cyclotriphosphazenes Bearing Chalcones Derivatives, Phosphorus, Sulfur, and Silicon and the
Related Elements, 185:3, 628-633, DOI: 10.1080/10426500902893217
To link to this article: http://dx.doi.org/10.1080/10426500902893217
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Phosphorus, Sulfur, and Silicon, 185:628–633, 2010
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500902893217
SYNTHESIS AND CHARACTERIZATION OF
CYCLOTRIPHOSPHAZENES BEARING CHALCONES
DERIVATIVES
Zainab Ngaini and Norashikin I. Abdul Rahman
Department of Chemistry, Faculty of Resource Science and Technology,
Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia
A series of new cyclotriphosphazenes bearing chalcones derivatives, N3P3Cl5[OC6H4
CH CHC(O)C6H4OCnH2n+1] and N3P3[OC6H4CH CHC(O) C6H4OCnH2n+1]6, has
been synthesized. A convenient synthetic method was performed from the reaction of hex-
achlorocyclotriphosphazenes with one and six equivalents of (E)-3-(4-(alkyloxy)phenyl)-
1-(4-hydroxyphenyl)prop-2-en-1-one (2a–c). The compounds differ in the length of alkyl
groups, CnH2n+1, where n = 10, 12, and 14, respectively. All the products were obtained in
high yields. The structures of the synthesized compounds were defined by elemental analysis,
IR, 1H, 13C, and 31P NMR.
Keywords Alkyloxy; chalcones; hexachlorocyclotriphosphazenes
INTRODUCTION
Phosphazenes are compounds that contain a framework of alternating phosphorus and
nitrogen atoms, either in cyclic or linear form.1 Studies on linear, cyclo-, and polyphosp-
hazenes have been widely investigated. These compounds are reported to possess interesting
biomedical properties2 and have promising applications such as effective flame retardants
for fiber materials.3 Nucleophilic substitutions of hexachlorocyclotriphosphazenes have
been widely reported. The reaction involves the substitution of chlorines by various nucle-
ophiles such as phenols,4,5 amine,6 and azo compounds.7
Synthesis of cyclotriphosphazenes bearing cinnamates8 and hydroxychalcones9 as
side groups had been studied for photosensitive phosphazenes that could undergo photo-
cross-linking reaction under UV irradiation. In photochemistry, chalcone derivatives have
been reported to possess outstanding nonlinear optic properties for optical communications
and optical electronics,10 liquid crystal displays,11,12 and alignment film.13 Chalcones have
also been reported to promote excellent blue light transmittance and good crystallability,14,15
high photosensitivity, and thermal stability for various crystalline electro-optical devices.
Received 10 February 2009; accepted 13 March 2009.
The authors thank Universiti Malaysia Sarawak and Ministry of Science, Technology and Innovation
(MOSTI) for financial support through FRGS/01(03)/608/2006(41).
Address correspondence to Dr. Zainab Ngaini, Department of Chemistry, Faculty of Resource Science
and Technology, Universiti Malaysia Sarawak 94300, Kota Samarahan, Sarawak, Malaysia. E-mail: nzainab@
frst.unimas.my, nzainab@gmail.com
628

CYCLOTRIPHOSPHAZENES BEARING CHALCONES
629
In this article, we report the new synthesis of cyclotriphosphazenes bearing chal-
cone derivatives (E)-3-(4-(alkyloxy)phenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2a–c),
which could be used as a reaction models for various crystalline electro-optical devices.
RESULTS AND DISCUSSION
The series of chalcone derivatives (E)-3-(4-(alkyloxy)phenyl)-1-(4-hydroxyphenyl)
prop-2-en-1-one (2a–c)16 were first prepared via Claisen–Schmidt condensation of 1a–c17
and 4-hydroxyacetophenone by the route depicted in Scheme 1.
O
O
O
O
MeOH
Reflux
K2CO3, TBAI
MEK
H
H3C
H
+
R-Br
+
RO
OH
OH
RO
HO
1a, R = C10H21
1b, R = C12H25
1c, R = C14H29
2a, R = C10H21
2b, R = C12H25
2c, R = C14H29
Scheme 1 Synthesis of chalcone derivatives 2a–c.
The IR spectra of chalcone derivatives 2a–c showed the presence of bands at
2849–2922 cm−1, which were attributed to the introduction of the long alkyl chain via
etherification of 4-hydroxybenzaldehyde. The presence of a new C O stretching frequency
at 1636–1648 cm−1 also substantiated the formation of the title compound. The structures
1
1
of compounds 2a–c were further confirmed by H and 13C NMR spectra. The H NMR
spectra of 2a–c show the new peaks attributed to trans vinylic proton at 7.39–7.41 and
7.67–7.77, respectively, with a coupling constant, Jab 15 Hz. The 13C NMR spectra show
the chemical shift of C O within the chemical shift range of 188.73–190.14 ppm, and
C C peaks appeared at 127.48–130.18 ppm and 144.25–144.44 ppm, respectively. The
elemental analysis is comparable to the theoretical value.
The synthetic route for the preparation of N3P3Cl5[OC6H4CH CHC(O)C6H4OCn
H2n+1] 3a–c and N3P3[OC6H4CH CHC(O) C6H4OCnH2n+1]6 4a–c is illustrated in
Scheme 2. Monosubsubstituted cyclotriphosphazenes 3a–c were obtained from the reac-
tion of hexachlorocyclotriphosphazenes with one equivalent of chalcone derivatives 2a–c
R
Cl
P
N
N
N
K2CO3
Cl
P
P
Cl
Cl
O
Cl
Cl
Cl
Acetone
reflux
P
N
+
N
P
N
3a, R = OC6H4CH=CHC(O)-C6H4OC10H21
3b, R = OC6H4CH=CHC(O)-C6H4OC12H25
3c, R = OC6H4CH=CHC(O)-C6H4OC14H29
Cl
Cl
P
Cl
Cl
OH
RO
K2CO3
2a, R = C10H21
2b, R = C12H25
2c, R = C14H29
R
R
Acetone,
reflux
P
N
N
N
P
R
P
R
R
R
4a, R = OC6H4CH=CHC(O)-C6H4OC10H21
4b, R = OC6H4CH=CHC(O)-C6H4OC12H25
4c, R = OC6H4CH=CHC(O)-C6H4OC14H29
Scheme 2 Synthesis of 3a–c and 4a–c.

630
Z. NGAINI AND N. I. ABDUL RAHMAN
in the presence of K2CO3 in acetone. The higher polarity of the acetone18 was believed to
increase the rate of reaction compared to THF9 and dioxane.19 The structures of the com-
pounds were characterized by elemental analysis, IR, 1H, 13C, and 31P NMR spectroscopy.
The IR spectra showed P N stretching vibrations at 1162 cm−1, which−a1re characteristic
of cyclotriphosphazenes.20,21 The absorption bands observed at 951 cm were attributed
to the presence of the P O C bond.22 The characteristic peak at 1658 cm−1 corresponded
to C O. The 31P NMR spectra showed two resonances as a triplet and doublet at 12.53
ppm and 23.00 ppm, respectively, with a coupling constant, J 60 Hz, which implied the
replacement of one chlorine from the cyclotriphosphazene ring for the monosubstituted
phosphazenes.23 The 1H and 13C NMR data also confirmed the substitution of 2a–c, with
the chemicals shift moved slightly downfield.
The reaction of hexachlorocyclotriphosphazenes with six equivalents of 2a–c under
the same reaction conditions afforded 4a–c in high yield. The IR spectra showed the
characteristic absorption bands at 1162 cm−1, which were attributed to P N stretching
vibrations. The presence of new bands at 951 cm−1 in 4a–c is a strong indication for the
formation of P O C bonds. 31P NMR showed a single resonance at δ 9.03 ppm, which
implied complete chlorine replacement.23 The data obtained from elemental analysis, 1H,
and 13C NMR showed good agreement to the corresponded structures.
CONCLUSION
A series of monosubstituted cyclotriphosphazenes was obtained from the reaction of
hexachlorocyclotriphosphazenes with one equivalent of chalcone derivatives 2a–c. Hex-
asubstituted cyclotriphosphazenes were obtained from the reaction of hexachlorocyclot-
riphosphazenes with six equivalents of chalcone derivatives 2a–c via replacement of all the
chlorine atoms.
EXPERIMENTAL
Materials
4-Hydroxybenzaldehyde, 4-hydroxyacetophenone, and 1-bromoalkanes were ob-
tained from Merck Company and used without further purification. Hexachlorocyclot-
riphosphazene was provided by Aldrich and was recrystallized from hexane. Acetone was
distilled from calcium hydride under nitrogen before use. All other reagents and solvent
were used as received. The reactions were performed under dry nitrogen.
Measurements
The melting points of the synthetic products were determined on a melting point
measurement device and uncorrected. Infrared spectra were recorded on a (FT-IR) 1605
Shimadzu Spectrometer as neat liquid films technique between sodium chloride plate or
1
potassium bromide pellet (KBr) for solid materials. H NMR spectra were recorded at
500 MHz on a Jeol Delta 2-NMR. 13C NMR was recorded at 125.77 MHz. The chemical
shifts for 31P NMR are relative to the internal standard of 85% phosphoric acid.

CYCLOTRIPHOSPHAZENES BEARING CHALCONES
631
4-Decyloxybenzaldehyde (1a)17
A mixture of 4-hydroxybenzaldehyde (6.11 g, 50 mmol), K2CO3 (8.29 g, 60 mmol),
bromodecane (12.40 mL, 60 mmol), and TBAI (1.85 g, 5 mmol) in MEK (150 mL) was
heated at reflux for 12 h. The mixture was filtered and cooled at room temperature. Water
(30 mL) was added to the filtrate, and the layers were separated. The aqueous layer was
extracted with dichloromethane (2 × 30 mL). The combined layers were washed with water
(2 × 20 mL), dried (MgSO4), filtered, and concentrated in vacuo. The crude product was
purified by column chromatography (eluting with 1:20 ethyl acetate:petroleum ether) to
afford 1a (8.69 g, 66%) as a viscous brown oil. The FTIR and NMR data were consistent
with the reported literature.16 The same general procedure gave compounds 1b–c, with the
scale (mL, mmol, [bromoalkane]) and yields given below.
4-Dodecyloxybenzaldehyde (1b). Bromododecane (14.38 mL, 60 mmol).
Yield: 13.03 g, 90%. The FTIR and NMR data were consistent with the reported
literature.16
4-Tetradecyloxybenzaldehyde (1c). Bromotetradecane (16.31 mL, 60 mmol).
Yield: 11.78 g, 74%. The FTIR and NMR data were consistent with the reported literature.16
(E)-3-(4-Decyloxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2a)16
A mixture of 4-hydroxyacetophenone (2.72 g, 20 mmol) and 1a (5.25 mL, 20 mmol)
in 60 mL of methanol was added under stirring to a solution of KOH (4.04 g, 72 mmol)
in methanol (10 mL). The mixture was heated at reflux for 10 h. The reaction was cooled
to room temperature and acidified with cold diluted HCl (2N). The resulting precipitate
was filtered, washed, and dried. The crude product was recrystallized from hexane:ethanol
(7:1) to give 2a (6.83 g, 54%) as yellow crystals. The FTIR and NMR data were consistent
with the reported literature.16. The same general procedure gave compounds 2b–c, with the
scale (mmol, mL [1b–c]) and yields given below.
(E)-3-(4-Dodecyloxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2b).
1b (5.81 mL, 20 mmol). Yield: 8.32 g, 52%. The FTIR and NMR data were consistent
with the reported literature.16
(E)-3-(4-Tetradecyloxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2c).
1c (6.37 g, 20 mmol). Yield: 5.51 g, 54%. The FTIR and NMR data were consistent
with the reported literature.16
Preparation of N3P3Cl5[OC6H4CH CHC(O)C6H4OC10H21] (3a)
A mixture of hexachlorocyclotriphosphazenes (0.5 g, 1.44 mmol), 2a (0.55 g,
1.44 mmol), and K2CO3 (2.87 g) in acetone (40 mL) was heated at reflux temperature
for 1 h. The mixture was allowed to cool to room temperature and filtered. The filtrate was
dried, filtered, and concentrated in vacuo. The crude solid was recrystallized from acetone
to afford 3a (0.18 g, 38%) as yellow solid. Mp 86–87◦C; (Found: C, 43.25; H, 4.42; N, 6.07.
C25H31Cl5N3O3P3 Requires C, 43.41; H, 4.52; N, 6.07%); νmax (thin films/cm−1) 1211,
1159, 1185 (P N), 871 (P O C); δH (500 MHz, CDCl3) 0.86 (3H, t, 1 × CH3), 1.26–1.78
(16H, m, 8 × CH2), 3.98 (2H, t, 1 × CH2), 6.90 (2H, d, J 8.05, Ar H), 7.34 (1H, d, J 15.45,
1 × olefinic H), 7.37 (2H, d, J 8.60, Ar H), 7.57 (2H, d, J 8.05, Ar H), 7.76 (1H, d, J
15.45, 1 × olefinic H), 8.04 (2H, d, J 8.05, Ar H); δC (125.77 MHz, CDCl3) 14.09, 22.64,
25.96, 29.10, 29.33, 29.43, 29.52, 29.52, 31.86, 68.20, 114.94, 118.84, 121.46, 127.07,

632
Z. NGAINI AND N. I. ABDUL RAHMAN
130.35, 130.44, 136.89, 145.50, 152.15, 152.23, 161.53, 188.88; δP (200 MHz, CDCl3)
12.53 (t), 23.00 (d) J 60 Hz. The same general procedure gave compounds (3b–c) and
(4a–c), with the scale (gram, mmol [2b–c]), reaction times, yields, and spectroscopy data
given below.
Preparation of N3P3Cl5[OC6H4CH CHC(O)C6H4OC12H25] (3b). 2b (0.59 g,
1.44 mmol), 1 h. Yield: 0.28 g, 49%. Mp 77–78◦C; (Found: C, 45.04; H, 4.21; N, 5.44.
C27H35Cl5N3O3P3 Requires C, 45.06; H, 4.90; N, 5.84%); νmax (thin films/cm−1) 1212,
1159, 1185 (P N), 872 (P O C); δH (500 MHz, CDCl3) 0.86 (3H, t, 1 × CH3), 1.25–1.79
(20H, m, 10CH2), 3.99 (2H, t, 1 × CH2), 6.09 (2H, d, J 8.60, Ar H), 7.05 (2H, d, J 8.60,
Ar H), 7.34 (1H, d, J 15.45, 1 × olefinic H), 7.37 (2H, d, J 8.60, Ar H), 7.56 (2H, d,
J 8.55, Ar H), 7.77 (1H, d, J 15.45, 1 × olefinic H); δC (125.77 MHz, CDCl3) 13.90,
14.11, 22.67, 26.00, 29.12, 29.34, 29.52, 29.56, 29.56, 29.62, 29.62, 31.89, 114.79, 118.84,
121.45, 127.08, 130.36, 136.90, 145.51, 152.16, 152.42, 161.54, 188.90; δP (200 MHz,
CDCl3) 12.54 (t), 23.31 (d) J 60 Hz.
Preparation of N3P3Cl5[OC6H4CH CHC(O)C6H4OC14H29] (3c). 2c (0.59 g,
1.44 mmol), 1 h. Yield: 0.28 g, 50%. Mp 75–76◦C; (Found: C, 45.96; H, 5.22; N, 5.55.
C29H39Cl5N3O3P3 Requires C, 46.58; H, 5.26; N, 5.62%); νmax (thin films/cm−1) 1212,
1186, 1160 (P N), 871 (P O C); δH (500 MHz, CDCl3) 0.80 (3H, t, 1 × CH3), 1.18–1.72
(24H, m, 12 × CH2), 3.92 (2H, t, 1 × CH2), 6.82 (2H, d, J 8.55, Ar H), 7.27 (1H, d, J
15.45, 1 × olefinic H), 7.29 (2H, d, J 8.55, Ar H), 7.49 (2H, d, J 8.60, Ar H), 7.70 (1H,
d, J 15.45, 1 × olefinic H), 8.00 (2H, d, J 8.05, Ar H); δC (125.77 MHz, CDCl3) 14.10,
22.66, 25.96, 29.11, 29.11, 29.34, 29.56, 29.56, 29.62, 29.62, 29.62, 30.95, 31.89, 68.20,
114.93, 118.83, 121.43, 121.47, 127.07, 130.35, 130.44, 136.89, 145.49, 152.14, 152.23,
161.53, 188.87; δP (200 MHz, CDCl3) 12.53 (t), 23.30 (d) J 60 Hz.
Preparation of N3P3[OC6H4CH CHC(O)-C6H4OC10H21]6 (4a). 2a (1.64 g,
4.31 mmol), 2 h. Yield: 1.53 g, 88%. Mp 126–127◦C; (Found: C, 74.30; H, 7.58; N, 1.05.
C150H186N3O18P3 Requires C, 74.69; H, 7.76; N, 1.74%); νmax (thin films/cm−1) 3062 (C-H
in aromatic), 1162 (P N), 893 (P O C); δH (500 MHz, CDCl3) 0.89 (3H, t, 1 × CH3),
1.28–1.79 (16H, m, 8 × CH2), 3.98 (2H, t, 1 × CH2), 6.87 (2H, d, J 8.0, Ar H), 7.05 (2H,
d, J 8.0, Ar H), 7.30 (1H, d, J 15.45, 1 × olefinic H), 7.49 (2H, d, J 8.60, Ar H), 7.64
(1H, d, J 15.45, 1 × olefinic H), 7.86 (2H, d, J 8.55, Ar H); δC (125.77 MHz, CDCl3)
14.09, 22.65, 26.00, 29.16, 29.30, 29.38, 29.55, 29.55, 31.86, 68.15, 76.75, 114.75, 118.46,
120.98, 127.16, 130.19, 130.52, 135.82, 145.30, 153.21, 161.39; δP (200 MHz, CDCl3)
9.03 (s, 3P, N3P3 ring).
Preparation of N3P3[OC6H4CH CHC(O)-C6H4OC12H25]6 (4b). 2b (1.76 g,
4.31 mmol), 2 h. Yield: 1.31 g, 75%. Mp 122–123◦C; (Found: C, 75.18; H, 8.23; N, 1.67.
C162H210N3O18P3 Requires C, 75.41; H, 8.20; N, 1.63%); νmax (thin films/cm−1) 3068 (C-H
in aromatic), 1162 (P N), 893 (P O C); δH (500 MHz, CDCl3) 0.86 (3H, t, 1 × CH3),
1.25–1.78 (20H, m, 10H2), 3.95 (2H, t, 1 × CH2), 6.85 (2H, d, J 8.60, Ar H), 7.03 (2H,
d, J 8.0, Ar H), 7.29 (1H, d, J 15.45, 1 × olefinic H), 7.47 (2H, d, J 8.55, Ar H), 7.62
(1H, d, J 15.45, 1 × olefinic H), 7.85 (2H, d, J 8.0, Ar H); δC (125.77 MHz, CDCl3)
14.07, 22.64, 25.98, 29.13, 29.30, 29.56, 29.59, 29.59, 30.84, 31.86, 67.94, 68.11, 114.72,
118.41, 120.97, 127.13, 130.16, 130.50, 135.79, 145.25, 153.18, 161.35, 188.67; δP (200
MHz, CDCl3) 9.03 (s, 3P, N3P3 ring).
Preparation of N3P3[OC6H4CH CHC(O)-C6H4OC14H29]6 (4c). 2c (1.88 g,
4.31 mmol), 2 h. Yield: 1.48 g, 78%. Mp 128–129◦C; (Found: C, 74.53; H, 7.77; N,
1.63. C162H210N3O18P3 Requires C, 75.41; H, 8.20; N, 1.63%); νmax (thin films/cm−1
)
3068 (C-H in aromatic), 1162 (P N), 887 (P O C); δH (500 MHz, CDCl3) 0.80 (3H, t,

CYCLOTRIPHOSPHAZENES BEARING CHALCONES
633
1 × CH3), 1.19–1.72 (24H, m, 12 × CH2), 3.90 (2H, t, 1 × CH2), 6.79 (2H, d, J 7.4, Ar H),
6.98 (2H, d, J 8.05, Ar H), 7.22 (1H, d, J 15.45, 1 × olefinic H), 7.41 (2H, d, J 7.40,
Ar H), 7.56 (1H, d, J 15.45, 1 × olefinic H), 7.79 (2H, d, J 7.45, Ar H); δC (125.77 MHz,
CDCl3) 14.09, 22.66, 26.01, 29.17, 29.34, 29.38, 29.59, 29.63, 29.65, 29.65, 29.65, 31.89,
68.15, 114.75, 118.47,120.98, 127.16, 130.52, 135.82, 145.29, 153.21, 161.39, 188.74; δP
(200 MHz, CDCl3) 9.03 (s, 3P, N3P3 ring).
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