Surface modification of nylon 6,6 using a carbene insertion approach

Article abstract of DOI:10.1039/b514205a

The diazirine functionalised fluorenone, 3-[3-(trifluoromethyl)diazirin-3- yl]phenyl-9-oxo-9H-fluorene-2-carboxylate was synthesised to act as a model compound capable of modifying a wide variety of polymeric substrates. Photochemical activation of the diazirine moiety of the fluorenone derivative was utilised to afford highly reactive carbenes capable of insertion into or addition to a wide variety of functionalities. In this paper the photoinduced attachment of a fluorenone derivative to nylon 6,6 has been studied using UV-visible spectroscopic analysis. Incorporation of the fluorenone chromophore onto the backbone of nylon at different loading levels and after different coating cycles has been investigated and is detailed in this paper. the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.

Full text of DOI:10.1039/b514205a

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PAPER
www.rsc.org/njc | New Journal of Chemistry
Surface modification of nylon 6,6 using a carbene insertion approach
Anton Blencowe,a Kevin Cosstickb and Wayne Hayes*a
Received (in Cambridge, UK) 6th October 2005, Accepted 2nd November 2005
First published as an Advance Article on the web 17th November 2005
DOI: 10.1039/b514205a
The diazirine functionalised fluorenone, 3-[3-(trifluoromethyl)diazirin-3-yl]phenyl-9-oxo-9H-
fluorene-2-carboxylate was synthesised to act as a model compound capable of modifying a wide
variety of polymeric substrates. Photochemical activation of the diazirine moiety of the fluorenone
derivative was utilised to afford highly reactive carbenes capable of insertion into or addition to a
wide variety of functionalities. In this paper the photoinduced attachment of a fluorenone
derivative to nylon 6,6 has been studied using UV-visible spectroscopic analysis. Incorporation of
the fluorenone chromophore onto the backbone of nylon at different loading levels and after
different coating cycles has been investigated and is detailed in this paper.
decompose with extrusion of nitrogen to afford carbenes. In
1. Introduction
preliminary experiments the tosylhydrazone-dye was con-
The development of compounds capable of functionalising
verted to its sodium salt and then photolysed in methanol
multiple substrates has been the subject of intense research. An
and 2,2,2-trifluoroethanol. The reaction in methanol afforded
area that has attached considerable interest is the modification
the desired O–H insertion product only in low yield, whereas
of polymeric substrates with multifunctional dyes and reac-
exclusive formation of the desired ether occurred with 2,2,2-
tants. Included amongst these types of reagents are ‘universal
trifluoroethanol. Photolysis of the diazirine-dye in cyclohex-
dyes’ which possess high affinities for multiple substrate types.
ane and methanol resulted in low yields of the desired C–H
A notable example is the vinyl sulfone azo dye developed1 by
and O–H insertion products, respectively. More recently,
Lee et al., which possesses the ability to act as a disperse dye
Moloney and co-workers have employed carbenes derived
and a reactive dye. When applied to polyester–cotton blends
from the thermal treatment of diaryldiazomethanes to intro-
the vinyl sulfone moiety reacts with the nucleophilic groups
duce electron-rich aromatic systems onto the surface of var-
present in the cotton whilst the dye is also dispersed efficiently
ious polymeric substrates, including polystyrene, polythene,
into the hydrophobic polyester fibres. Freeman and Sokolow-
nylon, silica, controlled pore glass and poly(tetrafluoroethy-
lene).7 Reaction of the electron-rich aromatic systems intro-
ska-Gajda have developed naphtholazo dyes that can act as
disperse or ionic dyes if they are converted into their cationic
duced onto the substrate surface with diazonium salts resulted
form.2 More recently, Freeman and co-workers have devel-
in intense coloration which was found to be consistent with
oped a pyrazoline based reactive-disperse dye that has high
initial modification of the polymeric substrate via the carbene
affinities for polyester, nylon and wool fibres.3 Although such
insertion approach employed.
universal dyes have shown significant promise these reagents
In the light of these developments our studies have focused
are still limited to use with particular polymeric substrates as a
on the development of a functionalised carbene that is capable
result of their chemical reactivity and selectivity.
of reacting in a single step with any substrate type upon
An alternative class of reactants that is capable of reacting
exposure to suitable stimuli (for example light). The carbene
with almost all organic functionalities are carbenes. The ability
derivative has been designed so that it can be mixed with the
of carbenes to react rapidly with any groups within their
substrate in an inert form as a diazirine. The carbene is then
liberated from the diazirine8 upon irradiation. In the present
vicinity, including C–H, O–H, N–H and S–H bonds and
C–C double bonds, render these reagents ideal for functiona-
study, the ability of a photoinduced carbene containing fluor-
lising organic substrates. As a result of the highly reactive and
enone to react with nylon 6,6 was investigated. The diazirine
indiscriminate nature of carbenes they have been applied
functionalised dye was mixed initially with nylon 6,6 in
widely for the modification of substrates to afford biofunc-
different weight to weight ratios and irradiated using a 125
tional materials.4 In addition, carbene insertion approaches
W high pressure mercury vapour lamp. After exhaustive
have also been adopted for the general modification of poly-
washing, the amount of chromophore incorporated on to the
meric materials to afford functionalised substrates with
nylon substrate was assessed using UV-visible spectroscopic
enhanced physical and chemical characteristics.5 Braybrook
analysis.
et al. have developed tosylhydrazone and diazirine functiona-
lised azobenzene dyes,6 which, under photolytic conditions
2. Results and discussion
a The School of Chemistry, The University of Reading, Whiteknights,
Reading, UK RG6 6AD. E-mail: w.c.hayes@reading.ac.uk
b DuPont, P.O. Box 401, Wilton Site, Middlesbrough, Cleveland, UK
TS6 8JJ
2.1 Synthesis of diazirine functionalised fluorenone 1
The diazirine functionalised fluorenone 1 was synthesised effici-
ently (87%) from 3-(3-hydroxylphenyl)-3-(trifluoromethyl)
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Scheme 2 Insertion products generated via photochemical reaction of
1 with acetic acid, n-butylamine and N-butylbutyramide.
Scheme 1 Synthesis of diazirine functionalised fluorenone derivative
1, (a) n-BuLi, Et2NCOCF3 (b) NH2OH ꢂ HCl (c) TsCl, NEt3, DMAP
(d) NH3, ꢁ78 1C (e) Ag2O (f) BBr3 (g) fluorenone-2-carboxylic acid,
DCC, DMAP.
shown by 1H NMR spectroscopic analysis.12 Photolysis of 1 in
n-butylamine afforded secondary amines (such as 7, Scheme 2)
arising from insertion of carbenes into the amine N–H bonds
and C–H insertion products (such as 8, Scheme 2) as revealed
by 1H and 19F NMR spectroscopic analysis.13–15 19F NMR
spectroscopic analysis of the product obtained upon photo-
lysis of 1 in N-butylbutyramide revealed an extensive number
of resonances corresponding to the trifluoromethyl group of a
complex mixture of products arising from insertion of the
carbene into N–H and C–H bonds. In addition, the carbonyl
oxygen could have acted as an election donor, reacting with a
carbene to initially form an ylide which could react further to
afford secondary products.15,16 UV-visible spectroscopic ana-
lysis of the crude product mixtures obtained from photo-
chemical reaction of the fluorenone 1 with acetic acid, n-
butylamine and N-butylbutyramide exhibited strong adsorp-
tion maxima at 277 nm (in 2,2,2-trichloroethanol) correspond-
ing to the fluorenone moiety.
diazirine 2 and fluorenone-2-carboxylic acid (Scheme 1) using
the coupling reagent N,N0-dicyclohexylcarbodiimide (DCC)
and a catalytic amount of 4-(N,N-dimethylamino)pyridine
(DMAP).
The hydroxyl diazirine 2 was constructed in 6-steps (overall
yield of 78%) from commercially available 3-bromophenol
(Scheme 1) using a method based upon the synthesis of
trifluoromethyl aryl diazirines first reported by Brunner
et al.9 3-Bromophenol was protected initially as the methyl
ether 3 using sodium hydroxide in the presence of iodo-
methane. Reaction of the methyl ether 3 with n-butyllithium
and N,N-diethyltrifluoroacetamide10 afforded the respective
trifluoromethyl ketone, 2,2,2-trifluoro-1-(3-methoxyphenyl)
ethanone, which was then converted to the corresponding
oxime 4 via reaction with hydroxylamine hydrochloride. For-
mation of the diaziridine 5 was achieved by converting the
oxime 4 to its O-tosyl derivative, O-tosyl-2,2,2-trifluoro-1-
(3-methoxyphenyl)ethanone oxime, which was then reacted
with liquid ammonia to yield the diaziridine 5. Oxidation of 5
using Ag2O afforded 3-(trifluoromethyl)-3-(3-methoxy-
phenyl)diazirine, which was then deprotected with boron tri-
bromide to afford the hydroxyl diazirine 2.
The ability of the carbene generated from 1 to insert into the
X–H (X = C, O or N) bonds of acetic acid, n-butylamine and
N-butylbutyramide demonstrated that, upon photochemical
activation, the carbene would be capable of inserting into the
chain ends and polymer backbone of nylon 6,6. In such
circumstances it would be possible to attach several fluorenone
molecules to a single polymer chain.
The fluorenone derivative 1 was a bright yellow crystalline
solid similar in appearance to that of fluorenone-2-carboxylic
acid. UV-visible spectroscopic analysis of 1 in 2,2,2-trichlo-
roethanol revealed a strong absorption band (lmax = 277 nm)
with a pronounced shoulder at l = 304 nm resulting from the
conjugated aromatic system of the fluorenone moiety. The
adsorption resulting from the p–p* transition of the diazo
moiety of the diazirine could be observed as a weak adsorption
band centred at l = 369 nm. The molar absorptivity coeffi-
cient of 1 in 2,2,2-trichloroethanol was determined to be
62 407 m2 molꢁ1 at l = 277 nm.
Photolysis of benzophenone derivatives such as 9-fluore-
none can also generate diradical species that are capable of
reacting with nylon. To determine if the fluorenone moiety of 1
would react with nylon in this manner, 9-fluorenone was
dissolved in cyclohexane and acetic acid (0.15 M) and irra-
diated for a period of 12 hours. Subsequent removal of the
solvent and analysis of the residue via 1H NMR spectroscopic
analysis revealed that ca. 10% of 9-fluorenone reacted with
cyclohexane via hydrogen abstraction (Scheme 3),17 whereas
no reaction occurred when acetic acid was used. These results
imply that, upon irradiation, the fluorenone carbonyl of 1
could become photo-excited leading to hydrogen abstraction
from the alkyl backbone of nylon and the formation of a
9-hydroxyfluorenyl radical (see 9, Scheme 3).18 The radicals
produced in this process could then react further to afford a
variety of products including alcohols, alkanes, ketones and
carboxylic acids or undergo radical–radical coupling.17
2.2 Photochemisty of diazirine functionalised fluorenone 1
In order to simulate the reaction between the carbene gener-
ated from 1 and nylon 6,6, model reactions were conducted
involving representative substrates. Irradiation (using a 125 W
high pressure mercury lamp) of the fluorenone 1 in acetic acid,
n-butylamine and N-butylbutyramide11 (0.03 M) for a period
of 12 hours resulted in high yields (495%) of the desired
insertion products. Photochemical reaction of 1 with acetic
acid resulted in exclusive formation of the ester 6 (Scheme 2) as
2.3 Dyeing of nylon 6,6
As a result of the poor solubility of nylon 6,6 in common
organic solvents, attachment of the model fluorenone
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Scheme 3 Photochemical reaction of 9-fluorenone with cyclohexane.
derivative via photochemical means was conducted in the solid
phase. Anhydrous diethyl ether solutions of 1 were added to
nylon 6,6 powder (with dimensions varying from 44 to 440
mm) in a 5 mL vial, vortexed and then sonicated under argon.
To produce thin layers of the nylon powder suitable for
irradiation the solvent was removed from the mixture under
reduced pressure (0.1 mbar) at 50 1C, whilst being spun at ca.
400 rpm. The vials were flushed with argon, sealed and placed
3 cm away from a 125 watt high pressure mercury vapour
lamp and irradiated for 12 hours. The resultant nylon powder
was then washed with chloroform, tetrahydrofuran (THF) and
methanol, dried (0.1 mbar) at 40 1C and analysed using UV-
visible spectroscopic analysis. To eliminate chemisorption as a
possible mechanism of dyeing, blanks were run in parallel
using the same procedure without irradiation. In order to
eliminate nylon photolytic degradation as a possible source of
contaminates that could absorb within the UV-visible region
under investigation, nylon powder was irradiated for 72 hours
under argon. Samples of nylon powder were removed every 12
hours and analysed via UV-visible spectroscopic analysis.
Changes were not observed in the UV-visible spectrum of
the nylon powder after each 12 hour period of irradiation and
thus it was concluded that the nylon used was stable under the
photolytic conditions employed.
only increased slightly with an increase in the mixing ratio,
reaching a plateau at a diazirine : nylon mixing ratio of 1 : 2.
These results indicate that there is a limit to the loading of the
diazirine derivative at which additional chromophore is not
incorporated onto the substrate regardless of the amount of
diazirine employed. At higher loadings (diazirine : nylon 1 : 1)
it is proposed that the carbenes produced from the fluorenone
derivative 1 are in close enough proximity to react with other
molecules of 1, thus limiting the reaction of the carbene with
the nylon substrate.
The percentage of chromophore incorporated into the nylon
compared to the amount of fluorenone derivative 1 employed
initially is shown in Fig. 1 (K). At high mixing ratios the
amount of chromophore incorporated is o1% and was found
to increase exponentially as the mixing ratio decreased result-
ing in ca. 9% incorporation of the chromophore at a diazir-
ine : nylon mixing ratio of 1 : 1000. The results confirm that at
high mixing ratios more of the fluorenone derivative 1 is in
contact with itself as opposed to the substrate. Thus, at high
loadings only a small proportion of the applied fluorenone
derivative 1 is in close enough proximity to react with the
nylon polymer chains upon photoactivation of the diazirine
moiety. In addition, the adsorption of radiation by the fluor-
enone derivative 1 at the surface of the solid mixture may
hinder the activation of the diazirine moiety of other molecules
of 1 just below the surface. UV-visible and NMR spectro-
scopic analyses of the washings obtained when high mixing
ratios (e.g. diazirine : nylon, 1 : 1) were employed provided
evidence for unreacted diazirine. In addition, a singlet reso-
nance at dF ꢁ68.5 ppm in the 19F NMR spectrum19 of the
washings revealed the presence of the azine derivative20 (see
10, Fig. 2) of the fluorenone 1. The formation of azine
derivatives in the solution phase chemistry of diazirine func-
tionalised azobenzene dyes has also been reported by Bray-
brook et al.6 At lower diazirine : nylon mixing ratios (o1 : 10)
the diazirine 1 was not detected via either UV-visible or 19F
NMR spectroscopic analysis of the washings, implying com-
plete decomposition of the diazirine moiety of 1.
UV-visible spectroscopic analysis of the modified nylon
obtained using different ratios of diazirine to nylon indicated
that the fluorenone derivative 1 was incorporated successfully
at each of the mixing ratios employed (diazirine : nylon, 1 : 1,
1 : 2, 1 : 5, 1 : 10, 1 : 20, 1 : 100, 1 : 1000). A graph of absorbance
at 277 nm versus the mixing ratio (diazirine/nylon) employed
revealed an exponential relationship in which the absorbance
was found to increase as the mixing ratio increased (Fig. 1, m).
At mixing ratios of o0.1 (diazirine : nylon 1 : 10) the absor-
bance of the modified nylon was found to increase steadily
with an increase in the mixing ratio. However, at higher
mixing ratios (40.1) the absorbance of the modified nylon
To determine if the amount of chromophore incorporated
after additional dyeing cycles followed a linear relationship the
nylon was mixed with the fluorenone derivative 1, irradiated,
washed and then the procedure was repeated a total of six
times. The modified nylon was analysed via UV-visible
Fig. 1 m = Absorbance of functionalised nylon at 277 nm vs. mixing
ratio (diazirine/nylon). K = Percentage incorporation of chromo-
phore vs. mixing ratio of diazirine and nylon (diazirine/nylon).
Fig. 2 Structure of azine 10.
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Instrumentation
Thin-layer chromatography (TLC) was performed on alumi-
nium sheets coated with Merck silica gel 60 F254. Developed
TLC plates were stained with potassium permanganate solu-
tion or scrutinised under 254 nm UV light. Column chroma-
tography was performed using SI60 Sorbent silica (40–63 mm)
supplied from VWR international. Melting points were deter-
mined using a Mettler FP61 melting point apparatus and are
uncorrected. 1H Nuclear magnetic resonance (NMR) spectro-
scopy was performed on either a Bruker DPX250 (250 MHz)
or a Bruker AMX400 (400 MHz) spectrometer (using TMS
and the deuterated solvent as lock and residual solvent). 13C
NMR spectroscopy was performed on Bruker AC250 (62.8
MHz) or Bruker AMX400 (100 MHz) spectrometers. 19F
NMR spectroscopy was performed on a Bruker DPX250
(235 MHz) spectrometer (using CFCl3 as internal reference).
Infrared spectroscopy was performed using a Perkin Elmer
1720-X spectrometer with the samples analysed as thin films.
UV-visible analysis was performed on a Perkin Elmer Lambda
25 UV/Vis spectrometer using methanol or 2,2,2-trichlor-
oethanol as the solvent. Mass spectra (MS) were obtained
either using a Fisons VG Autospec instrument or Finnigan
MAT 95 instrument operating in chemical ionisation mode,
using ammonia as the impact gas.
Fig. 3 Absorbance of functionalised nylon at 277 nm vs. the coating
cycle for the diazirine : nylon mixing ratios of 1 : 1, 1 : 10, 1 : 100 and
1 : 1000, respectively.
spectroscopic analysis after each coating cycle. A graph of
absorbance at 277 nm against the coating cycle at four
different diazirine : nylon mixing ratios (1 : 1, 1 : 10, 1 : 100
and 1 : 1000) revealed a linear relationship for each mixing
ratio employed, in which the absorbance increased with each
coating cycle (Fig. 3). In addition to the UV-visible spectro-
scopic results obtained it was possible to observe a difference
in the depth of colour after each coating cycle. For example,
after six coating cycles (at a 1 : 1 diazirine : nylon mixing ratio)
the colour of the nylon powder had changed from a bright
white to a light yellow.
Preparation of fluorenone derivative 1
3-[3-(Trifluoromethyl)diazirin-3-yl]phenyl-9-oxo-9H-fluorene-
2-carboxylate 1. Fluorenone-2-carboxylic acid (510 mg, 2.27
mmol) was dissolved in anhydrous dichloromethane (35 mL)
under argon and DCC (692 mg, 3.41 mmol) and DMAP (2
mol%, 5 mg, 0.04 mmol) were added. After a period of 10
minutes, the diazirine 2 (361 mg, 1.78 mmol) was added and
the reaction was stirred at room temperature in the dark for 20
hours. The insoluble N,N0-dicyclohexylurea was removed by
filtration and the filtrate was concentrated in vacuo to afford a
yellow solid. Purification via column chromatography on silica
(1 : 1 hexane : dichloromethane) afforded the fluorenone deri-
vative 1 as a bright yellow solid, 638 mg (87%); Td 113.2 1C;
UV-visible (MeOH): l = 372 nm (NQN); IR nmax/cmꢁ1 (thin
film) 739, 1056, 1151, 1188, 1241, 1605, 1713, 1719 and 3070;
1H NMR (250 MHz, CDCl3, TMS) dH 7.07–7.08 (m, 1H,
ArH), 7.12 (dquin, J = 1.8, 7.9 Hz, 1H, ArH), 7.33 (ddd, J =
1.0, 2.3, 8.2 Hz, 1H, ArH), 7.42 (td, J = 1.1, 7.4 Hz, 1H, ArH),
7.49 (t, J = 7.9 Hz, 1H, ArH), 7.58 (td, J = 1.2, 7.5 Hz, 1H,
ArH), 7.65 (dt, J = 1.0, 7.5 Hz, 1H, ArH), 7.68 (dd, J = 0.6,
7.8 Hz, 1H, ArH), 7.75 (dt, J = 1.0, 7.4 Hz, 1H, ArH), 8.35
(dd, J = 1.6, 7.8 Hz, 1H, ArH), 8.45 (dd, J = 0.6, 1.6 Hz, 1H,
ArH) ppm; 13C NMR (62.8 MHz, CDCl3) dC 28.7 (q, J = 40.3
Hz, CN2), 119.9 (ArCH), 120.4 (ArCH), 121.4 (ArCH), 121.5
(q, J = 271.5 Hz, CF3), 123.2 (ArCH), 124.1 (ArCH), 124.8
(ArCH), 125.8 (ArCH), 130.1 (ArCH), 130.2 (ArCC), 130.5
(ArCH), 131.3 (ArCC), 134.8 (ArCC), 135.1 (ArCC), 135.1
(ArCH), 137.0 (ArCH), 143.5 (ArCC), 149.7 (ArCC), 151.4
(CO2), 164.2 (ArCO), 192.8 (CO) ppm; 19F NMR (235 MHz,
CDCl3, CFCl3) dF ꢁ65.5 (s, CF3) ppm; CI-MS ([M]+ ꢁ N2)
calculated for C22H11F3O3: 380.0660, found: 380.0651.
3. Conclusions
A diazirine functionalised fluorenone has been synthesised
efficiently and employed as a model compound to demonstrate
the applicability of carbene insertion processes for the modi-
fication of polymeric substrates such as nylon 6,6. Photoche-
mical reaction of the fluorenone derivative with substrates
representative of the functional groups present in nylon
afforded high yields of carbene insertion products. Solid state
photochemical reactions of the fluorenone derivative with
nylon were conducted at different diazirine : nylon mixing
ratios and UV-visible spectroscopic analysis of the modified
nylon revealed that the fluorenone moiety was incorporated
successfully into the nylon and enabled quantification of the
amount of chromophore present. In addition, repeating the
photo-induced modification cycle resulted in a linear increase
in the amount of chromophore incorporated.
4. Experimental
Materials
Reagents were purchased from either Lancaster, Acros Chi-
mica or the Aldrich Chemical Company and were used with-
out further purification, unless stated. Diethyl ether and
tetrahydrofuran (THF) were distilled from benzophenone
and sodium. Dichloromethane was distilled from CaH2. Sam-
ples of nylon 6,6 (stabilised with copper halide) were supplied
by DuPont. GC grade 2,2,2-trichloroethanol (99.9+%) was
used for UV-visible spectroscopic analysis.
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3-(Trifluoromethyl)-3-(3-hydroxylphenyl)diazirine 2. 3-(Tri-
fluoromethyl)-3-(3-methoxyphenyl)diazirine (11.43 g, 52.9
mmol) was dissolved in anhydrous dichloromethane (180
mL). Boron tribromide (7.55 mL, 79.4 mmol) was added
dropwise over a period of 30 minutes and the mixture was
stirred in the dark under argon for 24 hours. Water (30 mL)
was added carefully followed by dichloromethane (100 mL)
and water (200 mL). After 1 hour the organic phase was
removed and the aqueous phase was extracted with dichloro-
methane (3 ꢃ 150 mL). The combined organic extracts were
dried (MgSO4), filtered and concentrated in vacuo at 40 1C to
afford an orange oil. Purification via column chromatography
on silica (3 : 2 hexane : dichloromethane), afforded the diazir-
ine 2 as a very pale yellow oil, 10.36 g (97%); UV-visible
(MeOH): l = 361 nm (NQN); IR nmax/cmꢁ1 (thin film) 1154,
cmꢁ1 (thin film) 1154, 1202, 1256, 1343, 1466, 1492, 1584, 1600
and 1718; 1H NMR (250 MHz, CDCl3, TMS) dH 3.88 (s, 3H,
OCH3), 7.23–7.28 (m, 1H, ArH), 7.46 (t, J = 16.1 Hz, 1H,
ArH), 7.57 (s, 1H, ArH), 7.65–7.68 (m, 1H, ArH) ppm; 13C
NMR (62.8 MHz, CDCl3) dC 55.9 (CH3), 114.3 (ArCH), 117.0
(q, J = 291.3 Hz, CF3), 122.7 (ArCH), 123.2 (ArCH), 130.5
(ArCH), 131.5 (ArCC), 160.4 (ArCO), 180.8 (q, J = 35.1 Hz,
CO) ppm; 19F NMR (235 MHz, CDCl3, CFCl3) dF ꢁ71.6 (s,
CF3) ppm; CI-MS ([M]+) calculated for C9H7F3O2: 204.0398,
found: 204.0400.
2,2,2-Trifluoro-1-(3-methoxyphenyl)ethanone oxime 4. 2,2,2-
Trifluoro-1-(3-methoxyphenyl)ethanone (7.92 g, 30.0 mmol)
and hydroxylamine hydrochloride (5.56 g, 80.0 mmol) were
dissolved in ethanol (150 mL) and maintained under reflux for
2 hours before the mixture was neutralised with 4 M NaOH.
After a further 2 hours under reflux, the mixture was neutra-
lised again and the solution was concentrated in vacuo. The
resulting residue was dissolved in water (200 mL) and ex-
tracted with diethyl ether (4 ꢃ 150 mL). The combined organic
extracts were washed with 0.25 M HCl (200 mL), water (200
mL), dried (MgSO4), filtered and concentrated in vacuo to
1
1204, 1272, 1355, 1454, 1500, 1588, 1612 and 3334; H NMR
(250 MHz, CDCl3, TMS) dH 5.00 (s, 1H, OH), 6.67 (m, 1H,
ArH), 6.71–6.75 (m, 1H, ArH), 6.85–6.90 (m, 1H, ArH), 7.27
(t, J = 7.9 Hz, 1H, ArH) ppm; 13C NMR (62.8 MHz, CDCl3)
dC 28.7 (q, J = 40.5 Hz, CN2), 113.9 (ArCH), 117.2 (ArCH),
119.2 (ArCH), 122.4 (q, J = 274.6 Hz, CF3), 130.6 (ArCH),
131.2 (ArCC), 156.2 (ArCO) ppm; 19F NMR (235 MHz,
CDCl3, CFCl3) dF ꢁ65.6 (s, CF3) ppm; CI-MS ([MH]+
ꢁ
afford the oxime 4 as a clear viscous oil, 8.07 g (97%); IR nmax/
N2) calculated for C8H5F3O: 175.0371, found: 175.0365.
cmꢁ1 (thin film) 1137, 1197, 1251, 1343, 1430, 1489, 1582,
1
1602, 1702 and 3346; H NMR (250 MHz, CDCl3, TMS) dH
1-Bromo-3-methoxybenzene 3. 3-Bromophenol (10.02 g, 58
mmol) was dissolved in THF (150 mL) and KOH pellets (6.50
g, 116 mmol) were added. The mixture was stirred for a period
of 30 minutes under argon and then MeI (5.4 mL, 87 mmol)
was added. After 16 hours water (300 mL) and diethyl ether
(100 mL) were added and the mixture was stirred for a further
30 minutes. The organic phase was removed and the aqueous
phase was extracted with diethyl ether (3 ꢃ 150 mL). The
combined organic extracts were dried (MgSO4), filtered and
concentrated in vacuo to afford 3 as a pale yellow oil, 10.70 g
(99%); IR nmax/cmꢁ1 (thin film) 766, 838, 1039, 1230, 1246,
3.84 (s, 3H, OCH3), 7.00–7.09 (m, 3H, 3ArH), 7.37–7.44 (m,
1H, ArH), 8.81 (br s, 1H, OH) ppm; 13C NMR (62.8 MHz,
CDCl3) dC 55.8 (OCH3), 114.7 (ArCH), 116.7 (ArCH), 121.0
(q, J = 274.8 Hz, CF3), 121.2 (ArCH), 127.5 (ArCC), 130.2
(ArCH), 147.8 (q, J = 32.4 Hz, CN), 159.8 (ArCO) ppm; 19
F
NMR (235 MHz, CDCl3, CFCl3) dF ꢁ67.3 (s, CF3) ppm;
CI-MS ([M]+) calculated for C9H8F3O2N: 219.0507, found:
219.0508.
O-Tosyl-2,2,2-trifluoro-1-(3-methoxyphenyl)ethanone oxime.
Oxime 4 (12.18 g, 55.6 mmol), triethylamine (11.7 mL, 83.4
mmol), DMAP (50 mg) and p-toluenesulfonyl chloride (10.60
g, 55.6 mmol) were dissolved in dichloromethane (200 mL)
under argon and stirred at room temperature for 36 hours in
the dark. The resulting mixture was washed with water (2 ꢃ
150 mL) and 0.25 M HCl (2 ꢃ 150 mL). The combined
aqueous washings were washed with dichloromethane (2 ꢃ
100 mL) and the organic extracts were collected together,
washed with saturated NaHCO3 (150 mL), dried (MgSO4),
filtered and concentrated in vacuo to afford the O-tosyl oxime,
O-tosyl-2,2,2-trifluoro-1-(3-methoxyphenyl)ethanone oxime
1
1284, 1429, 1477, 1575, 1590 and 2937; H NMR (250 MHz,
CDCl3, TMS) dH 3.79 (s, 3H, OCH3), 6.81–6.85 (m, 1H, ArH),
7.05–7.06 (m, 1H, ArH), 7.08–7.17 (m, 2H, 2ArH) ppm; 13C
NMR (62.8 MHz, CDCl3) dC 55.8 (CH3), 113.5 (ArCH), 117.5
(ArCH), 123.2 (ArCBr), 124.2 (ArCH), 130.9 (ArCH), 160.8
(ArCO) ppm; CI-MS ([M]+) calculated for C7H7OBr: 185.9,
found: 185.9.
2,2,2-Trifluoro-1-(3-methoxyphenyl)ethanone. 1-Bromo-3-
methoxybenzene 3 (5.00 g, 26.9 mmol) was dissolved in
anhydrous THF (100 mL) and cooled to ꢁ78 1C under argon.
1.6 M n-BuLi in hexanes (16.8 mL, 26.9 mmol) was added over
a period of 5 minutes and the mixture was stirred for a further
5 minutes. N,N-Diethyltrifluoroacetamide (5.01 g, 29.9 mmol)
was added over a period of 5 minutes and the mixture was
stirred for 2 hours. The mixture was poured into a saturated
NH4Cl (300 mL) solution and stirred rapidly for an hour
before extraction with diethyl ether (3 ꢃ 100 mL). The
combined organic extracts were dried (MgSO4), filtered and
concentrated in vacuo to afford a pale yellow oil. Purification
via column chromatography on silica (3 : 2 hexane : dichloro-
methane) afforded the ketone, 2,2,2-trifluoro-1-(3-methoxy-
as a white solid, 20.43 g (98%); mp 111.0–111.6 1C; IR nmax
/
cmꢁ1 (thin film) 1154, 1178 1194, 1255, 1291, 1390, 1487, 1578
and 1606; 1H NMR (250 MHz, CDCl3, TMS) dH 2.48 (s, 3H,
CH3), 3.82 (s, 3H, OCH3), 6.88–6.89 (m, 1H, ArH), 6.93–6.96
(m, 1H, ArH), 7.03–7.07 (m, 1H, ArH), 7.35–7.41 (m, 3H,
3ArH), 7.89 (AA0XX0 system, 2H, 2ArH) ppm; 13C NMR
(62.8 MHz, CDCl3) dC 22.2 (CH3), 55.8 (OCH3), 114.3
(ArCH), 117.6 (ArCH), 119.9 (q, J = 277.6 Hz, CF3), 120.9
(ArCH), 126.3 (ArCC), 129.6 (2ArCH), 130.3 (2ArCH), 130.4
(ArCH), 131.6 (ArCC), 146.6 (ArCC), 154.4 (q, J = 33.7 Hz,
CN), 159.9 (ArCO) ppm; 19F NMR (235 MHz, CDCl3,
CFCl3) dF ꢁ67.4 (s, CF3) ppm; CI-MS ([M]+) calculated for
C16H14O4F3NS: 373.0596, found: 373.0599.
phenyl)ethanone, as a pale yellow oil, 4.83 g (88%); IR nmax
/
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006
New J. Chem., 2006, 30, 53–58 | 57

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3-(Trifluoromethyl)-3-(3-methoxyphenyl)diaziridine 5. O-To-
syl-2,2,2-trifluoro-1-(3-methoxyphenyl)ethanone oxime (20.01
g, 53.6 mmol) was dissolved in dichloromethane (80 mL) and
added dropwise over a period of 30 minutes to liquid ammonia
(200 mL) at ꢁ78 1C under argon. After 12 hours the mixture
was gradually warmed to room temperature. Water (200 mL)
and dichloromethane (100 mL) were added and the mixture
was stirred for 1 hour before removal of the organic phase and
further extraction of the aqueous phase with dichloromethane
(3 ꢃ 100 mL). The combined organic extracts were dried
(MgSO4), filtered and concentrated in vacuo to afford the
diaziridine 5 as a crystalline solid, 11.60 g (99%); mp 40.1–
40.6 1C; IR nmax/cmꢁ1 (thin film) 1164, 1217, 1247, 1370, 1461,
in an identical manner and washed in an identical manner,
however, they were stored in the dark for 12 hours as opposed
to being irradiated.
Acknowledgements
AB would like to thank DuPont Fellows Forum for funding.
References
1 J. J. Lee, N. K. Han, W. J. Lee, J. H. Choi and J. P. Kim, Color.
Technol., 2003, 119, 134.
2 J. Sokolowska-Gajda and H. S. Freeman, Dyes Pigm., 1990, 14, 35.
3 P. Suwanruji, H. S. Freeman and D. Zhao, Color. Technol., 2004,
120, 220.
1
1586, 1604 and 3256; H NMR (250 MHz, CDCl3, TMS) dH
4 A. Blencowe and W. Hayes, Soft Matter, 2005, 1, 178.
5 (a) U. G. Kang, J. W. Raksis, C. L. Kehr and C. A. Ferrin, in
Polymer Surface Modification using Aqueous Stable Diazo Solution,
US Patent 5,075,427, 1991; (b) R. Reiner and H. Kaiser, in Process
and Compounds for Surface Modification of Macromolecular Sub-
stances, US Patent 4,309,453, 1982; (c) D. A. Olsen and A. J.
Osterras, in Carbene Modified Organic Surfaces, Canadian Patent
812,736, 1969; (d) A. W. Morgan and J. S. Swenson, in Process for
the Chemical Modification of the Solid Surface of a Polymer, US
Patent 3,376,278, 1968; (e) P. J. Pullan, in Dyeing Textile Fibres,
Br. Patent 1,395,885, 1975; (f) P. J. Pullan, in A Method of
Colouring a Fabric or Film, Br. Patent 1,412,963, 1975; (g) C.
Holstead, R. A. Jeffreys, L. Shuttleworth and R. S. Wickham, in
Photographic Materials, Br. Patent 1,344,993, 1974; (h) C. Hol-
stead, L. Shuttleworth, J. Griffiths and P. J. Pullan, in Dyeing or
Treating Films and Fibres, Br. Patent 1,344,991, 1974; (i) M. G.
Moloney, W. Ebenezer and K. Awenat, in Process for the Surface
Functionalisation of Polymeric Substrates using Diarylcarbenes as
Reactive Intermediates, US Patent 6,699,527, 2004; (j) K. Awenat,
W. Ebenezer and M. G. Moloney, in A Method for the Functiona-
lisation of Polymeric Substrates, Br. Patent PCT/GB99/03629,
1999.
2.22 (d, J = 8.8 Hz, 1H, NH), 2.76 (d, J = 8.8 Hz, 1H, NH),
3.83 (s, 3H, OCH3), 6.96–7.00 (m, 1H, ArH), 7.15–7.16 (m,
1H, ArH), 7.19–7.22 (m, 1H, ArH), 7.31 (t, J = 8.0 Hz, 1H,
ArH) ppm; 13C NMR (62.8 MHz, CDCl3) dC 55.7 (OCH3),
58.4 (q, J = 35.8 Hz, CN2), 114.0 (ArCH), 116.2 (ArCH),
120.7 (ArCH), 123.9 (q, J = 278.3 Hz, CF3), 130.3 (ArCH),
133.4 (ArCC), 160.1 (ArCO) ppm; 19F NMR (235 MHz,
CDCl3, CFCl3) dF ꢁ75.9 (s, CF3) ppm; CI-MS ([MH]+)
calculated for C9H9F3N2O: 219.0745, found: 219.0748.
3-(Trifluoromethyl)-3-(3-methoxyphenyl)diazirine. Diaziri-
dine 5 (11.40 g, 52.3 mmol) was dissolved in diethyl ether
(120 mL) and Ag2O (14.81 g, 63.8 mmol) was added. The
mixture was stirred vigorously in the dark under argon for 20
hours. The insoluble silver residues were removed by filtration
though a MgSO4–Celites layered sinter bed and the filtrate
was concentrated in vacuo to afford 3-(trifluoromethyl)-3-(3-
methoxyphenyl)diazirine as a very pale yellow oil, 11.01 g
6 D. R. Braybrook, M. G. Moloney, H. M. I. Osborn and W. J.
Norris, J. Photochem. Photobiol., A, 1993, 70, 171.
(98%); UV-visible (MeOH): l = 363 nm (NQN); IR nmax
/
cmꢁ1 (thin film) 1154, 1214, 1267, 1355, 1467, 1496, 1584, 1607
and 2962; 1H NMR (250 MHz, CDCl3, TMS) dH 3.73 (s, 3H,
OCH3), 6.61 (s, 1H, ArH), 6.68–6.72 (m, 1H, ArH), 6.84–6.89
(m, 1H, ArH), 7.23 (t, J = 8.1 Hz, 1H, ArH) ppm; 13C NMR
(62.8 MHz, CDCl3) dC 28.8 (q, J = 40.2 Hz, CN2), 55.7
(OCH3), 112.6 (ArCH), 115.6 (ArCH), 119.1 (ArCH), 122.5
(q, J = 274.7 Hz, CF3), 130.0 (ArCC), 130.4 (ArCH), 160.2
(ArCO) ppm; 19F NMR (235 MHz, CDCl3, CFCl3) dF ꢁ65.6
(s, CF3) ppm; CI-MS ([M]+ ꢁ N2) calculated for C9H7F3O:
188.0449, found: 188.0442.
7 K. M. Awenat, P. J. Davis, M. G. Moloney and W. Ebenezer,
Chem. Commun., 2005, 990.
8 Chemistry of Diazirines, ed. M. T. H. Liu, CRC Press, Boca Raton,
1987, vol. 1.
9 (a) J. Brunner, H. Senn and F. M. Richards, J. Biol. Chem., 1980,
255, 3313; (b) J. Brunner and G. Semenza, Biochemistry, 1981, 20,
7174.
10 J. H. Robson and J. Reinhart, J. Am. Chem. Soc., 1955, 77, 498.
11 C. Aubert, C. Huard-Perrio and M.-C. Lasne, J. Chem. Soc.,
Perkin Trans. 1, 1997, 2837.
12 (a) A. D. Allen, I. C. Ambridge, C. Che, H. Micheal, R. J. Muir
and T. T. Tidwell, J. Am. Chem. Soc., 1983, 105, 2343; (b) J.
Gaspar and A. Guerrero, Tetrahedron: Asymmetry, 1995, 6, 231.
13 (a) J. P. Richard, J. Am. Chem. Soc., 1989, 111, 6735; (b) F. Levrat,
H. Stoeckli-Evans and N. Engel, Tetrahedron: Asymmetry, 2002,
13, 2335; (c) Y. Gong, K. Kato and H. Kimoto, Bull. Chem. Soc.
Jpn., 2002, 75, 2637.
General procedure for dyeing of nylon 6,6 using the fluorenone
dye 1
Nylon 6,6 powder was washed prior to modification with
hexane, chloroform, THF and methanol (10 mL of each)
and dried under vacuum (0.1 mbar). Nylon powder was
weighed into a 5 mL vial and a solution of 1 in anhydrous
diethyl ether (1 mL) was added to afford weight to weight
diazirine : nylon mixing ratios of 1 : 1, 1 : 2, 1 : 5, 1 : 10, 1 : 20,
1 : 100 and 1 : 1000, respectively. The vial was spun at 400 rpm
and the solvent removed under reduced pressure (0.1 mbar) at
50 1C for 2 hours. The vial was flushed with argon, sealed and
irradiated using a 125 W high pressure mercury lamp for 12
hours. The modified nylon was washed three times with
chloroform, THF and methanol (3 ꢃ 10 mL of each) and
dried under vacuum (0.1 mbar) at 40 1C. Blanks were prepared
14 T. Okano, H. Sugiura, M. Fumoto, H. Matsubara, T. Kusukawa
and M. Fujita, J. Fluorine Chem., 2002, 114, 91.
15 A. Admasu, A. D. Gudmundsdottir, M. S. Platz, D. S. Watt, S.
´
Kwiatkowski and P. J. Crocker, J. Chem. Soc., Perkin Trans. 2,
1998, 1093.
16 M. S. Platz, W. R. White and D. A. Modarelli, Res. Chem.
Intermed., 1994, 20, 175.
17 J.-F. Rontani, Trends Photochem. Photobiol., 1997, 4, 125.
18 (a) R. S. Davidson, P. F. Lambeth, F. A. Younis and R. Wilson,
J. Chem. Soc. C, 1969, 2203; (b) R. S. Davidson and R. Wilson,
J. Chem. Soc. B, 1970, 71.
19 S. Benomar, B. Patel and A. E. Tipping, J. Fluorine Chem., 1990,
50, 207.
20 (a) M. T. H. Liu and K. Ramakrishnan, J. Org. Chem., 1977, 42,
3450; (b) M. P. Doyle, A. H. Devia, K. E. Bassett, J. W. Terpstra
and S. N. Mahapatro, J. Org. Chem., 1987, 52, 1619.
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58 | New J. Chem., 2006, 30, 53–58