Phenolysis of hexachlorocyclotriphosphazatriene

Article abstract of DOI:10.1002/hc.20127

The reactions of hexachlorocyclot-riphosphazatriene N₃P ₃Cl₆ (1) with the sodium salts of 2,4,6-trimethylphenol (2a), 4-tert-butyl-2-methylphenol (2b), 2-tert-butyl-4-methylphenol (2c) have been investigated, and monoarylo

Full text of DOI:10.1002/hc.20127

Heteroatom Chemistry
Volume 16, Number 4, 2005
Phenolysis of
Hexachlorocyclotriphosphazatriene
Saliha Begec¸1 and Adem Kılıc¸2
1Department of Chemistry, Faculty of Science and Arts, Inonu University,
TR-44280 Malatya, Turkey
2Department of Chemistry, Gebze Institute of Technology, 41400 Gebze, Kocaeli, Turkey
Received 11 March 2005
and -tetra phosphazenes were synthesized and char-
ABSTRACT: The reactions of hexachlorocyclot-
acterized [12]. Hexasubstituted derivatives of hex-
riphosphazatriene N3P3Cl6 (1) with the sodium
achlorocyclotriphosphazatriene (1) with 4-phenyl-
salts of 2,4,6-trimethylphenol (2a), 4-tert-butyl-2-
phenol [13], 4-methyl-, 4-hydroxy-, 4-tert-butyl-,
methylphenol (2b), 2-tert-butyl-4-methylphenol (2c)
4-phenoxyphenol [14], 2-methyl-, 2-phenylphenol
have been investigated, and monoaryloxy-substituted
[15], and o-dichloro- and o-dimethylphenol [16] have
phosphazenes N3P3Cl5OAr (3–5) were obtained.
been obtained.
ꢀ
C
2005 Wiley Periodicals, Inc. Heteroatom Chem 16:308–
We have previously investigated the reactions
of 1 with bulky phenols [17,18]. Here we report
the reactions of 1 with the sodium salts of 2,4,6-
310, 2005; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.20127
tri-methylphenol (2a), 4-tert-butyl-2-methylphenol
(2b), and 2-tert-butyl-4-methylphenol (2c). Mono-
substituted phosphazenes were obtained as major
products 3–5. We previously determined the solid-
state structure of 3 by single crystal X-ray diffraction
analysis [19].
INTRODUCTION
Cyclophosphazenes are an important family of in-
organic ring systems and most intensively studied
phosphorus–nitrogen compounds. Up to date many
compounds have been reported from the interac-
tions of cyclophosphazenes with amines and al-
cohols [1–11]; however, the reactions of cyclo-
phosphazenes with phenols are highly limited in
the literature. Some phenoxy-substituted cyclotri-
RESULTS AND DISCUSSION
The reaction of 1 with an equimolar amount of
sodium salts of 2a–c in THF gave the monosubsti-
tuted products 3, 4, 5.
Correspondence to: Saliha Begec¸; e-mail: sbegec@inonu.edu.tr.
2005 Wiley Periodicals, Inc.
c
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308

Phenolysis of Hexachlorocyclotriphosphazatriene 309
products were isolated by column chromatography
Fluka Ltd and used as purchased. Sodium salts were
prepared from the reaction of phenols 2a,2b,2c with
metallic sodium [23].
Reactions were monitored by using silica gel 60
F254 precoated TLC plates and separating conditions
were determined. The separation of products was
carried out by column chromatography using silica
gel 60 (230–400 mesh, Merck).
1
and characterized by elemental analysis, H-, 13C-,
31P- NMR spectrometry, and FT-IR. All these com-
pounds are air and moisture stable. No other product
could be isolated.
SPECTROSCOPIC STUDIES
The purity of the compounds was checked by
TLC and characterized by elemental analysis, 1H, 13C,
31P NMR spectrometry, and FT-IR. 1H, 13C, 31P NMR
spectra were recorded using a Bruker-Avence 500
NMR spectrometer operating at 500.13, 125 , 202.45
MHz respectively. All data was recorded for solutions
in CDCl3. The 1H and 13C NMR chemical shifts were
measured using SiMe4 (δ = 0) as an internal stan-
dard, and the 31P chemical shifts, using 85% H3PO4 as
an external standard. Melting points were measured
in open capillary tubes with an Elektrothermal-9200
melting point apparatus and were uncorrected. Mi-
croanalyses were carried out by the microanalytical
The aryl and alkyl C H stretching frequencies of
compounds 3–5 were observed at 3460–3495 cm−1
and 2924–2967 cm−1, respectively. P N bonds have
strong infra-red absorbances at 1100–1300 cm−1
[8,21,22].
Compounds 3,4,5, have absorbance bands at
1100–1286 cm−1 for ν(P N) and 593, 590, and 588
1
cm−1 for ν (PCl) respectively. H NMR spectra of
compounds 3–5 are relatively simple, but informa-
tive. The methyl protons resonate at δ = 2.25 (4-CH3)
and 2.34 (2-CH3) (in a 1:2 ratio) for 3. For 4, the pro-
tons of the tert-butyl group at the para position and
methyl group at the ortho position gave singlets at
δ = 1.29 and 2.34 (in a 3:1 ratio), respectively. The
protons of the methyl group at the para position and
tert-butyl group at the ortho position in 5 gave sin-
glets at δ = 2.22 and 1.32 (in a 1:3 ratio) respectively.
The 13C NMR signals of 3, CH3(ortho position) and
CH3(paraposition) are observed at δ = 17.67, 20.72,
respectively. The 13C NMR signals of 4, (CH3-ortho),
(C(CH3) para), (C(CH3) para), and (C-ipso) are ob-
served at 21.20, 30.28, 34.54, 147.51 respectively.
The 13C NMR signals for 5, (CH3 para), C(CH3)3
ortho), (C(CH3)3 ortho), C(5)-phenyl, C(3)-phenyl,
C(6)-phenyl, and C-ipso are observed at 16.98,
31.44, 34.22, 120.39, 124.03, 128.82, and 149.53
respectively.
¨
˙
service of TUBITAK-MAE, Gebze-Kocaeli (Turkey).
IR spectra were recorded on an ATI Unicam Matt-
son 1000-FTIR spectrophotometer in KBr disks and
were reported in cm−1 units.
Synthesis of 3
2a (5.37 g, 12 mmol) in THF (20 mL) was over a
period of 30 min to small pieces of Na (0.500 g,
24 mmol) in THF (10 mL) with stirring at 298 K,
with argon being passed over the reaction mixture.
Excess Na was removed by filtration and the solution
sodium 2,4,6-tri-methylphenoxide was cooled and
then frozen with a liquid nitrogen–acetone mixture.
To this solution, 1 (4.18 g, 12 mmol) in THF (40 mL)
was slowly added and the resulting mixture was al-
lowed to come to ambient temperature with constant
stirring [19,25]. After the reaction was completed,
the precipitated NaCl was filtered off and the solvent
was removed under vacuum. The solid residue was
dissolved in n-hexane and set aside to crystallize.
The compound 3 [2-(2,4,6-tri-methylphenoxo)-2,4,
4,6,6-pentachlorocyclo-2ꢀ5, 4ꢀ5, 6ꢀ5-triphosphaza-
triene] was obtained in 64% yield, mp 81◦C.
(Rf = 0.83 dichloromethane/n-hexane 1:10). Found:
C, 24.34; H, 2.46; N, 9.04% Calcd for N3P3Cl5C9-
H11O:C, 24.13; H, 2.45; N, 9.38%. IR (KBR): ꢁ(CH
aryl) 3489, ν(CH) 2924, ν(C C) 1482, ν(P N) 1222,
The 31P NMR spectra of 3,4,5 gave AB2 spin pat-
2
terns with JPNP = 60, 58 and 40.4 Hz respectively.
Chemical shifts, δ [P(OAr)Cl] = 11.83, 12.58, 8.89 and
δ (PCl2) = 22.18, 22.51, 22.40 are in good agreement
with the literature values [25].
EXPERIMENTAL
General Remarks
All reactions were performed under dry argon-
atmosphere using standard Schlenk techniques [23]
with previously dried solvents. The tetrahydrofu-
ran (THF) used as solvent was distilled under
argon from sodium benzophenone prior to use.
Hexachlorocyclotriphosphazatriene (99%) was pur-
chased from Aldrich Ltd. and purified by recrys-
tallization from n-hexane. 2,4,6-Trimethylphenol
(97%), 4-tert-butyl-2-methylphenol (98%), and 2-tert-
butyl-4-methylphenol (98%) were purchased from
1
1181 ν(PCl) 593 cm−1. NMR (CDCl3): H, δ 2.25 (s,
3H,CH -para), 2.34 (s, 6H, CH -ortho), 7.2 (s, 2H,
3
3
Ar-H); 13C, δ 17.67 (s, 2C, CH3-ortho), 20.72 (s, 1C,
CH3-para), 129.83 (s, 2C, 3-phenyl), 129.87 (s, 2C,
2-phenyl), 146.4 (s, 1C, C-ipso); 31P, AB2 pattern,
δA = 11.83, δB = 22.18, 2 JAB = 60 Hz.

310 Begec¸ and Kılıc¸
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3495, ν(CH) 2967, ν(C C) 1464, ꢁ(P N) 1119–1168,
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3
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30.28 (s, 3C, CH3-para), 34.54 (s, 1C, C(CH3)3-para),
119.68 (s, 1C, 3-phenyl), 127.68 (s, 2C, 5,6-phenyl),
147.51 (s, 1C, C-ipso) ; 31P, AB2 pattern, δA = 12.58,
δB = 22.51, 2 JAB = 58 Hz.
¨
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Synthesis of 5
2c (2.00 g; 12.1 mmol), Na (0.55 g; 24.2 mmol), and
1 (4.23 g; 12.1 mmol) were used following the
same procedure described for 3. The residue
chromatographed (silica gel: 100 g, eluent: dichloro-
methane/n-hexane 3:1), and 2-(2-tert-butyl-4-methyl-
phenoxo)-2,4,4,6,6-pentachlorocyclo-2ꢀ5, 4ꢀ5, 6ꢀ5-
triphosphazatriene) (5) was obtained in 57% yield.
Compound 5 is white crystal mp 59◦C. (Rf: 0.71
dichloromethane/n-hexane 1:10) (Found: C, 27.83;
H, 3.15; N, 8.62%, Calcd for N3P3Cl5C11H5O: C,
27.74; H, 3.82; N, 8.83%). IR (KBr): ν(CH aryl)
3460, ν(CH) 2945, ν (C C) 1500, ν(P N) 1100–1286,
1
ν(PCl) 588 cm−1. NMR (CDCl3): H, δ 1.32 (s, 9H,
C(CH )3-ortho), 2.22 (s, 3H, CH -para) 6.9 [dd, 1H,
3
3
C(5)-H], 7.08[s, 1H, C(3)-H], 7.24 [dd, 1H,C(6)-H];
13C, δ 16.98 (s, 1C, CH -para), 31.44 (s, 3C, C(CH3)3),
3
34.22 (s, 1C, C(CH3)3), 120.39 (s, 1C, C(5)-phenyl),
124.03 (s, 1C, C(3)-phenyl), 128.82 (s, 1C, C(6)-
phenyl), 149.53 (s, 1C, C-ipso). 31P AB2 pattern,
δA = 22.4, δB = 8.89, 2 JAB = 40.4 Hz.
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