Structural and fluorescence properties of phenolphthalein bridged cyclotriphosphazatrienes

Article abstract of DOI:10.1016/j.saa.2009.08.028

This study dealt with the reactions of hexachlorocyclotriphosphazatriene, N₃P₃Cl₆ (trimer) (1) with phenolphthalein (2) to give the phenolphthalein bridged compounds 3, 4 and 5. The phenolphthalein bridged cyclotriphosphaz

Full text of DOI:10.1016/j.saa.2009.08.028

Spectrochimica Acta Part A 74 (2009) 881–886
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Structural and fluorescence properties of phenolphthalein bridged
cyclotriphosphazatrienes
Gönül Yenilmez C¸ iftc¸ i∗, Mahmut Durmus¸ , Elif S¸ enkuytu, Adem Kılıc¸
Department of Chemistry, Gebze Institute of Technology, Gebze 41400, Kocaeli, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
This study dealt with the reactions of hexachlorocyclotriphosphazatriene, N3P3Cl6 (trimer) (1) with
phenolphthalein (2) to give the phenolphthalein bridged compounds 3, 4 and 5. The phenolphthalein
bridged cyclotriphosphazatriene derivatives are reported for the first time. The new compounds (3–5)
are characterized by elemental analysis, mass spectrometry, UV–vis, FT-IR, 1H, 31P NMR and fluorescence
spectroscopy. The more bridged phenolphthalein groups show the higher intensity of the absorption
bands in the UV–vis spectra. Fluorescence spectrum of compound 3 shows a small band in the lower
spectral range, while the spectra of compounds 4 and 5 show more intense and a band in higher spectral
range.
Received 13 April 2009
Received in revised form 31 July 2009
Accepted 7 August 2009
Keywords:
Cyclophosphazenes
Hexachlorocyclotriphosphazatriene
Phenolphthalein
Fluorescence
FT-IR
© 2009 Elsevier B.V. All rights reserved.
NMR
1. Introduction
found that ansa-derivatives are formed using sodium salts of diols
as reagents in polar solvents such as tetrahydrofuran (THF) [22,23].
Phosphazenes are important compounds from which a large
number of organophosphazenes can be derived by the reaction
with nucleophiles. Organophosphazenes find a variety of applica-
tions in science and technology [1]. Phosphazenes are made up of a
range of linear short chain or cyclic molecules and high polymers.
The chemical and physical properties of phosphazenes change with
the substituted side groups. For example, it is possible to design
materials with special properties such as inflammable textile fibers
and advanced elastomers [2], anticancer agents [3–5], hydraulic
fluids and lubricants [6,7], electrical conductivity [8], fertilizers
[9,10], flame retardant [11,12] and liquid crystalline [13–16]
properties.
The reaction of 2,2-dioxybiphenyl groups with the hexachloro-
cyclotriphosphazatriene are well known [24,25] and mono spiro
and mono ansa products are isolated from the reaction between 1
and 2,2-dioxybiphenyl [25]. There are also some works reported in
the literature about the reaction of 1 with some phenol and phenol
derivatives [26,27] and their fluorescence properties [28]. Informa-
tion on the reactions between 1 and polyphenols is not well known
and bridged products are found rarely [29]. Some phenoxy phos-
phazene derivatives are found in the literature about a potential
candidate of new type of dendritic emitting structures for solution
processed and hybrid organic light emitting diode (OLED) devices
[30].
The reactions of hexachlorocyclotriphosphazatriene with
difunctional alcohols are widely studied [17–19]. The four types of
products (spiro, ansa, open chain and bridged compounds) derived
from the reactions of 1 with diols are well established [20]. Reac-
tion of 1 with ethane-, 1,3-propane-, and 1,4-butane-diols (in the
presence of pyridine to neutralize the HCl formed) predominantly
gave spiro derivatives with 5-, 6-, 7-membered phosphate rings,
respectively whereas ansa derivatives were obtained only in small
yields [21]. A bridged derivative was observed as a minor product
with butanediol, indicating that chain length was a contributing
factor in determining the type of the compound [20]. It was also
Phenolphthalein is found in a variety of ingested products as
well as in some scientific applications such as food industry. It
can be incorporated easily in tablets, powders, and liquids due
to being odorless and tasteless. It has been commonly used as a
laxative, available worldwide as an over-the-counter chocolate or
gum laxative product [31]. Although there were several studies
including the phenolphthalein groups in the literature [32a,b],
there is no study which has been done about the reaction of
phenolphthalein with cyclophosphazenes.
This study aims to investigate for fluorescence proper-
ties of the phenolphthalein bridged cyclotriphosphazatriene
derivatives. For this purpose, reaction of phenolphthalein
with trimer in THF is investigated and some phenolphthalein
bridged cyclotriphosphazatriene compounds (3–5) (Scheme 1) are
characterized.
∗
Corresponding author. Tel.: +90 262 6053110; fax: +90 262 6053101.
E-mail address: yenilmez@gyte.edu.tr (G.Y. C¸ iftc¸ i).
1386-1425/$ – see front matter © 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2009.08.028

882
G.Y. C¸ iftc¸ i et al. / Spectrochimica Acta Part A 74 (2009) 881–886
Scheme 1.
2. Experimental
2.2. Methods
2.1. Materials
Elemental analyses were obtained using a Thermo Finnigan
Flash 1112 Instrument. Mass spectra were recorded on a Bruker
MicrOTOF LC–MS spectrometer using the electrospray ioniza-
tion (ESI) method; 35Cl values were used for calculated masses.
Analytical Thin Layer Chromatography (TLC) was performed on
Merck silica gel plates (Merck, Kieselgel 60, 0.25 mm thickness)
with F254 indicator. Column chromatography was performed
on silica gel (Merck, Kieselgel 60, 230–400 mesh; for 3 g crude
mixture, 100 g silica gel was used in a column of 3 cm in diameter
and 60 cm in length). 1H and 31P NMR spectra were recorded
in CDCl3 solutions on a Varian INOVA 500 MHz spectrometer
using TMS as an internal reference for 1H NMR and 85% H3PO4
as an external reference for 31P NMR. The FT-IR spectra were
recorded with Bio-Rad 175 FTS. The spectrum resolution was
Hexachlorocyclotriphosphazatriene (Otsuka Chemical Co. Ltd.)
was purified by fractional crystallization from n-hexane. Sodium
hydride (60% dispersion in mineral oil, Merck; prior to use
the oil was removed by washing with dry heptane followed
by decantation). Phenolphthalein (>99%), tetrahydrofuran (THF)
(≥99.0%), dichloromethane (≥99.0%), n-hexane (≥95.0%) were
obtained from Merck. THF was distilled over a sodium–potassium
alloy under an atmosphere of dry argon. All reactions were per-
formed under a dry argon atmosphere. Silica gel 60 (230–400
mesh) for column chromatography was obtained from Merck.
CDCl3 for NMR spectroscopy are obtained from Goss Scien-
tific.

G.Y. C¸ iftc¸ i et al. / Spectrochimica Acta Part A 74 (2009) 881–886
883
Table 1
Analytical data of cyclotriphosphazatrienes (3–5).
Comp.
Empirical formula
Analytical data (%)
Massa
M
Calculated
N
Found
N
[M+Na]+
C
H
C
H
3
4
5
C20H12Cl10N6O4P6
C40H24Cl14N9O8P9
C60H36Cl18N12O12P12
8.93
8.22
7.90
25.54
31.32
33.88
1.29
1.58
1.71
8.92
8.21
7.91
25.52
31.32
33.87
1.28
1.57
1.70
940
1533
2126
962.8
1555.7
2150.7
a
The ESI-MS spectra of compounds (3–5) show the [M+Na]+ and M molecular ion peaks.
Table 2
Selected FT-IR vibrations of compounds 3–5.
Compound
ꢀ(C–H)arom
ꢀ(C
ꢀ(C
ꢀ(P
N)
ꢀ(P–Cl)
ꢀ(P–O)
O)
C)
(1)
(2)
(3)
(4)
(5)
–
3061 m
3070 m
3060 m
3058 m
–
–
1258; 1169 s
–
1286; 1163 s
1288; 1165 s
1288; 1163 s
532; 608 s
–
524; 601 s
536; 604 s
526; 600 s
–
–
1740 vs
1778 s
1776 s
1774 s
1514 s
1503 s
1505 s
1503 s
1242; 1162 s
1246, 1160 s
1162, 1242 s
s: strong; m: medium; vs: very strong.
Fig. 1. (A) Mass spectrum compound of 5; (B) chloro pattern of compound 5; (C) computer analyzing of chloro pattern of compound 5.
2 cm−1 and 16 scans were recorded for all samples. The spectra
were recorded on the base of KBr pellet technique. UV–vis spectra
were recorded with a Shimadzu 2001 UV spectrophotometer.
Fluorescence emission spectra were recorded on a Varian Eclipse
spectrofluoremeter using 1 cm pathlength cuvettes at room
temperature.
n-hexane–THF (2:1) as eluent. Four products were observed on
TLC. The reaction mixture was filtered to remove the sodium chlo-
ride formed and the solvent removed under reduced pressure. The
resulting colorless oil was subjected to column chromatography,
using n-hexane–THF (2:1) as eluent. The first product was start-
ing material N3P3Cl6 (0.6 g, 12%), Rf = 0.82. The second product was
the mono-phenolphthalein bridge derivative (3) (1.26 g, 9.3%, m.p.
2.3. Synthesis
Table 3
2.3.1. Reaction of 1 with 2 in a 2:1 ratio to form compounds 3–5
Hexachlorocyclotriphosphazatriene (1) (5.0 g, 14.4 mmol) and
phenolphthalein (2) (1.94 g, 7.2 mmol) were dissolved in 100 mL
of dry THF under an argon atmosphere in a 250 mL three-necked
round-bottomed flask. The reaction mixture was cooled in an ice-
bath and NaH (60% oil suspension, 0.57 g, 14.4 mmol) in 40 mL of
dry THF was quickly added to a stirred solution under an argon
atmosphere. The reaction mixture was stirred for 5 days at room
temperature and the reaction followed on TLC silica gel plates using
1
31P { H} NMR parameters for compounds 3–5 in CDCl3.
Comp.
ı (31P NMR) (ppm)
Spin system
2J(PP) (Hz)
P(OCl)
A
PCl2
A, B
C, D
C
B
D
(3)
(4)
(5)
13.2
13.2
12.4
23.5
23.6
22.5
A2X
61.6
61.6
60.8
16.2
14.6
25.7
24.6
A2X, AꢀXꢀ2
A2X, AꢀXꢀ2
64.9
64.4

884
G.Y. C¸ iftc¸ i et al. / Spectrochimica Acta Part A 74 (2009) 881–886
Fig. 2. Proton-decoupled 31P NMR spectrum of the compound 3 in CDCl3.
Fig. 3. Proton-decoupled 31P NMR spectrum of the compound 4 in CDCl3.
58 ◦C), Rf = 0.64. The third product was the bis-phenolphthalein
bridge derivative (4) (0.32 g, 1.4%, oily), Rf = 0.43. The fourth product
was the isomeric tris-phenolphthalein bridge derivative (5) (0.25 g,
0.8%, m.p. 120 ◦C), Rf = 0.35 [n-hexane–THF (2:1)]. Analytical data
of cyclotriphosphazatrienes (3–5) were listed in Table 1. The ele-
mental analyses results and mass values were in agreement with
the proposed structures. The ESI-MS spectrum of compound (5)
was given in Fig. 1. Table 1 gives the empirical formula, molec-
ular weights (mass) and elemental analyses for the compounds
(3–5).
Fig. 4. 1H NMR spectra of (A) compound 3 and (B) compound 5 between 6.6 and 8 ppm in CDCl3.

G.Y. C¸ iftc¸ i et al. / Spectrochimica Acta Part A 74 (2009) 881–886
885
Table 4
1H NMR spectral data of compounds 3–5 in CDCl3.
.
Compounds
3
4
5
Ha, Hb, He, Hf
7.15–7.20
–
7.27–7.31
6.91–7.18
7.76–7.82
7.24–7.28
6.71–7.02
7.68–7.74
Haꢀ, Hbꢀ, Heꢀ, Hfꢀ
Hm
Hk
Hn
7.54 (td, 1H) [3JHnHk–Hm = 7.51]
7.47 (d, 1H) [3JHk–Hm = 7.76]
7.67(td,1H) [3JHpHm–Hn = 7.09]
–
7.67 (d, 1H) [3JHk–Hm = 7.94]
7.76–7.82
7.56 (td, 1H) [3JHpk–Hm = 7.82]
7.68–7.74
Hcꢀ, Hdꢀ, Hgꢀ, Hhꢀ
Hc, Hd, Hg, Hh
Hp
6.91–7.18
6.71–7.02
7.30 [3JHH = 8.45]
7.52–7.62
7.45 (d, 1H) [3JHH = 8.52]
7.80 (d, 1H) [3JHp–Hn = 7.66]
7.90 (d, 1H) [3JHp–Hn = 7.67]
7.91(d,1H) [3JHp–Hn = 7.91]
3. Results and discussion
and 7.90 ppm and some of them were distinguishable from each
other, 1H NMR spectra of 3 and 5 were shown as an example in Fig. 4.
In aromatic groups for 3, Hp, Hn, Hm, Hk protons were resonated at
7.90, 7.67, 7.54, 7.47 ppm, in which those have three bond-coupling
3.1. IR spectroscopy
3
FT-IR frequencies of various diagnostic bands for the compounds
constants, average of ca. JHH = 7.5 Hz (Fig. 4). The chemical shifts
(3–5) were given in Table 2. FT-IR spectra of the compounds 3–5
of some aromatic protons and coupling constants were shown in
Table 4. Values of chemical shifts for 3 were consistent with the
literature values [34].
showed characteristic stretching bands of ꢀ(C–H)arom and ꢀ(C
O)
between 3070–3058 cm−1 and 1740–1778 cm−1. The vibration
bands assignable to the stretching of the –P N– and P–Cl bands
for compounds 3–5 were observed at frequency in the range of
1163–1286 and 524–604 cm−1, respectively. These data were in
accordance with the reported values for phosphazene derivatives
[33].
3.3. Ground state electronic absorption and fluorescence spectra
The absorption and fluorescence spectra of phosphazene deriva-
tives were measured with diluted solutions (1 × 10−5 mol dm−3
)
in dichloromethane (DCM). Compounds 3–5 were excited at
240 nm for fluorescence emission studies. The absorption bands
were observed at 275 nm for all studied phenolphthalein bridged
cyclotriphosphazatriene compounds 3–5 in dichloromethane
(Fig. 5). The trend of absorption maximum among the corre-
sponding cyclotriphosphazatriene compounds was increased
with respect to number of the phenolphthalein group in
dichloromethane (Fig. 5). Fluorescence emission spectra of
phenolphthalein bridged cyclotriphosphazatriene compounds in
DCM were shown in Fig. 6. Fluorescence emission peaks at 311 nm
3.2. NMR spectroscopy
The proton-decoupled 31P (31P { H}) NMR spectral data of
1
bridge phenolphthalein derivatives of hexachlorocyclotriphos-
phazatriene (3–5) were given in Table 3. Compound 3 had two
different phosphorus environments within the molecule. 31P
1
{ H} NMR spectrum of compound 3 had A2X spin systems and
a typical example was shown in Fig. 2. In 31P{ H} NMR spectra,
1
the resonance belonging to the POCl group was observed at
13.2 ppm as triplet and PCl2 group was observed at 23.5 ppm as
doublet. In general, resonance of PORCl group should be observed
at ca. 30 ppm [23] but the compound 3 showed this resonance at
13.2 ppm may be due to the shielding effect. The chemical shift
values of PORCl groups for compound 4 were observed at 13.2
and 16.2 ppm, and PCl2 groups for compound 4 were observed
at 23.6 and 25.7 ppm, respectively (Table 3 and Fig. 3). The 31P
1
{ H} NMR spectral data of compounds 4 and 5 were very similar.
The chemical shift values of PORCl groups for compound 5 were
observed at 12.4 and 14.6 ppm, and PCl2 groups were observed
at 22.5 and 24.6 ppm, respectively. The coupling constants of all
compounds were very similar, i.e., about 61–64 Hz because of all
coupling constants between PCl2 and [P(OR)Cl] groups (Table 3).
The 1H NMR data also confirmed the structures of 3–5. The aro-
matic protons for all the compounds were observed between 6.72
Fig. 5. The absorption spectra of 3, 4 and 5 in dichloromethane. Concentration:
1 × 10−5 mol dm−3
.

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