Fluorous phthalocyanines and subphthalocyanines

Article abstract of DOI:10.1142/S1088424620500182

Incorporating fluorine atoms into a molecule can endow it with various unique properties that enable materials applications. Selective solubility in fluorous solvents is achieved by a high fluorine content and selective partitioning into perfluorinated liquids over organic and aqueous phases provides orthogonal opportunities for chemistry and materials assembly. Although there is a growing number of partially fluorinated molecules, there are insufficient structural design principles to produce diverse fluorous soluble dyes. Herein, we report the synthesis of six fluorous phthalocyanine and subphthalocyanine dyes, and study their properties in the fluorous phase. Phthalocyanines generally display limited solubility and we also observed apparent aggregation in the fluorous phase. However, the nonplanar subphthalocyanines showed greater solubility. Subphthalocyanines also displayed fluorescence in selected solvents, and their emissive properties were investigated. The materials described expand the library of fluorous dyes and provide insights for the design of new molecules with fluorous solubility.

Full text of DOI:10.1142/S1088424620500182

Published at https://www.worldscinet.com/jpp/
Journal of Porphyrins and Phthalocyanines
J. Porphyrins Phthalocyanines 2020; A–I
DOI: 10.1142/S1088424620500182
(pp. 9
Fluorous phthalocyanines and subphthalocyanines
KosukeYoshinaga, Leo Delage-Laurin and Timothy M. Swager*
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge,
MA 02139, USA
Received 27 March 2020
Accepted 28 March 2020
ABSTRACT: Incorporating fluorine atoms into a molecule can endow it with various unique properties
that enable materials applications. Selective solubility in fluorous solvents is achieved by a high
fluorine content and selective partitioning into perfluorinated liquids over organic and aqueous phases
provides orthogonal opportunities for chemistry and materials assembly. Although there is a growing
number of partially fluorinated molecules, there are insufficient structural design principles to produce
diverse fluorous soluble dyes. Herein, we report the synthesis of six fluorous phthalocyanine and
subphthalocyanine dyes, and study their properties in the fluorous phase. Phthalocyanines generally
display limited solubility and we also observed apparent aggregation in the fluorous phase. However, the
nonplanar subphthalocyanines showed greater solubility. Subphthalocyanines also displayed fluorescence
in selected solvents, and their emissive properties were investigated. The materials described expand the
library of fluorous dyes and provide insights for the design of new molecules with fluorous solubility.
KEYWORDS: phthalocyanine, zinc phthalocyanine, subphthalocyanine, fluorescence, fluorine,
aggregation, Faraday rotation.
the fluorine content of the molecule, and the typical
INTRODUCTION
requirement is that there is >50 weight percent fluorine
Fluorine incorporation provides properties of impor-
(wt% F) [7]. However, to date examples of dyes that
tance to materials chemistry and has found applications
in coating materials [1], pharmaceuticals [2], in vivo
partition to fluorous phases over organic phases are scarce
[9]. We are interested in expanding this area and have
drug delivery with perfluorocarbon nanoemulsions
produced fluorous soluble conjugated polymers [10, 11],
[3], and organic electronics [4]. Owing to fluorine’s
an array of fluorofluorophores [12], and fluorofluorescent
electronegativity and hydrophobicity, introducing even a
perylene bisimides [13]. Additionally, Cao and Sletten
single fluorine atom into a molecule can vastly influence
have recently demonstrated the opportunities of fluorous
its solubility and dipole moment [5]. As a result, there is
character and reported the first J-aggregate in fluorous
a growing interest in incorporating fluorine into organic
media [14] and the synthesis of a branched fluorous tag
semiconductingmaterialstoenhancedeviceperformance.
to create a fluorous soluble porphyrin [15]. All these
Incorporation of fluorine has also been found to improve
examples give rise to noteworthy materials properties,
chemical, thermal, and photochemical stability [6]. In
which highlights the uniqueness of the fluorous phase. As
some cases when the incorporation of fluorine atoms is
a result, we believe many applications await the discovery
high, compounds can phase separate from organic and
with the introduction of new fluorous materials.
aqueous phases [7]. In 1994, Horváth and Rábai labeled
Fluorous phthalocyanines and subphthalocyanines
liquids displaying this phase separation as “fluorous”
have attracted our interest as a result of their applications
phases, and demonstrated their utility in fluorous
in organic field-effect transistors [16], organic light-
biphasic catalysis [8]. Strategies to promote fluorous
emitting diodes [17], photovoltaics [18], nonlinear
phase formation and solubility therein mainly rely on
optical materials [19], and photodynamic therapy [20].
To date there are limited reports describing the properties
of phthalocyanines and subphthalocyanines in the
fluorous phase [21, 22]. Herein, we report the synthesis
*Correspondence to: Timothy M. Swager, tel: +1 (617) 253-
4423 email: tswager@mit.edu.
Copyright © World Scientific Publishing Company

B
K. YOSHINAGA ET AL.
of six fluorous soluble phthalocyanines (F-PCs) and
subphthalocyanines (F-SubPCs), and elaborate on their
structure–property relationship in the fluorous phase.
(66 and 128°C, respectively). F-PC-3 is slightly more
soluble in THF and HFE-7500 than F-PC-1 and F-PC-2,
-1
.
displaying a solubility of ~1 mg mL .
ThephotophysicalpropertiesofF-PCsaresummarized
in Table 1 and Figs 1d–1f. F-PC-1 is scarcely soluble in
heated THF and HFE-7500, and as a result its absorbance
spectra were taken in THF and HFE-7500 heated to near
their boiling temperatures. When solutions are cooled,
the spectra broaden and decrease in intensity (Fig. S1).
The heated solution was able to pass through a 0.2 mm
syringe filter; however, after cooling no perceptible color
was observed in filtered solutions, thereby indicating that
F-PC-1 precipitates. The absorbance spectra of F-PC-2
and F-PC-3 were also taken in THF and HFE-7500. The
absorbance spectra of F-PC-2 in THF resemble that
reported previously [21]. The absorbance of F-PCs in
THF showed the typical Soret and Q absorbance bands
for phthalocyanines; however, a consistent large change
in the spectra was observed for all of the F-PCs in
HFE-7500. Specifically, the relative peak intensity of the
Q band at ~690 nm decreased, while the relative peak
intensities of the Soret band at ~360 nm, as well as the
shoulder at ~650 nm increased. A decreased intensity
at the S0 à S1 band (labs ≈ 690 nm) and an increased
intensity of the absorbance at ~650 nm are suggestive of
H-aggregation in fluorous solvents [23, 24].
RESULTS AND DISCUSSION
Synthesis of F-PCs
The synthesis of F-PCs, as shown in Scheme 1, was
accomplished by adaptation of a method previously
reported in the literature [21]. In brief, phthalonitriles 1–3
werereactedwithzincacetateand1,8-diazabicyclo[5.4.0]
undec-7-ene (DBU) in n-pentanol to provide the desired
F-PCs in 32–43% yields. F-PCs were characterized by
MALDI-TOF MS, UV-vis absorbance spectroscopy,
FT-IR, and elemental analysis. The low solubility of
F-PCs in deuterated solvents and fluorous solvents
prevented the acquisition of nuclear magnetic resonance
(NMR) characterization.
Properties of F-PCs
The F-PCs displayed almost no solubility in any
organic solvents, regardless of wt% F. THF was the
only solvent that showed any, albeit low, solubility
-1
.
(<0.1 mg mL ) of F-PCs. Figs 1a–1c shows the
F-PCs partitioning into the fluorous solvent 2-(trifluo-
romethyl)-3-ethoxydodecafluorohexane (HFE-7500)
rather than dissolving in the organic solvent diethyl-
benzene (DEB). The HFE-7500 and DEB solvent
combination has a low interfacial tension and low
upper critical mixing temperature. Although the F-PCs
partitioned into HFE-7500, we observed precipitation
of F-PC-1 and F-PC-2 solutions from this solvent at
room temperature (Fig. S1). This was confirmed by
the observation that when solutions of F-PC-1 and
F-PC-2 were passed through a 0.2 mm syringe filter, the
solution was colorless, implying that they likely form
aggregates larger than 0.2 mm. The solubility of F-PCs
Synthesis of F-SubPCs
The synthesis of F-SubPCs, as shown in Scheme 2,
was accomplished by adapting procedures previously
reported in the literature [25]. In brief, the phthalonitrile
precursors 1–3 were prepared by an SNAr reaction of
the fluoroalkyl thiols and halogenated phthalonitriles.
Phthalonitriles 1–3 were then reacted with BCl3 to
provide the desired F-SubPCs in 13–29% yields. We note
that an alternative synthetic scheme wherein the SNAr
reaction installing the fluoroalkyl thiols is performed
on the halogenated subphthalocyanines did not produce
the desired F-SubPCs (Scheme S1). The F-SubPCs
were characterized by NMR, MALDI-TOF MS, UV-vis
absorbance, fluorescence spectroscopy, FT-IR, and
-1
.
can be increased to ~0.1 mg mL by heating the THF
and HFE-7500 solutions to their boiling temperatures
NC
CN
CnF2n+1
F2n+1Cn
S
S
HS
RF
N
Zn
N
(RF = C6F13 or C8F17
)
NC
R1
CN
R2
Zn(OAc)2
DBU
N
N
N
N
K2CO3
Cl
Cl
N
or
N
n-Pentanol
140 °C, 18 h
Acetone
60 °C, 16-48 h
NC
CN
1-3
S
S
S
CnF2n+1
F2n+1Cn
1: R1 = R2 =
2: R1 = R2 =
F
C8F17
C6F13
F-PCs
S
S
3: R1 = H, R2 =
C8F17
Scheme 1. Synthesis of fluorous phthalocyanines (F-PCs).
Copyright © World Scientific Publishing Company
J. Porphyrins Phthalocyanines

FLUOROUS PHTHALOCYANINES AND SUBPHTHALOCYANINES
C
Fig. 1. Chemical structure and fluorous partition of (a) F-PC-1, (b) F-PC-2, and (c) F-PC-3. Overlaid normalized absorbance
spectra of (d) F-PC-1, (e) F-PC-2, and (f) F-PC-3 in organic solvent THF and in fluorous solvent HFE-7500. Spectra for F-PC-1
obtained by heating the solutions to their boiling temperatures (66°C for THF, 128°C for HFE-7500).
Table 1. Summary of photophysical properties of F-PCs.
(PhMe), as well as the mentioned fluorous solvents.
We determined the fluorous partition coefficient (P) of
F-SubPCs by subjecting each compound to a 1:1 mixture
of PFMCH and PhMe, and quantifying the amount in each
layer by UV-vis absorbance spectroscopy (Figs 2a–2c).
F-SubPC-1, F-SubPC-2, and F-SubPC-3 had a P = 36
(97:3 in PFMCH/PhMe), 1.1 (53:47 in PFMCH/PhMe),
and 0.044 (4:96 in PFMCH/PhMe), respectively. From
these results, we confirm a trend that higher wt% F leads
to superior partitioning into fluorous solvents. The low
P of F-SubPC-3 may also be reflective of the fact that
it is a regioisomeric mixture, and therefore possesses an
asymmetric molecular structure.
Compound
l
abs, nm
Molar Extinction Coefficient
5
-1
-1
.
.
at labs, 10 L mol cm )
F-PC-1
698 (THF)
1.67 (THF)
650 (HFE-7500)
698 (THF)
2.37 (THF)
2.84 (THF)
F-PC-2
F-PC-3
650 (HFE-7500)
683 (THF)
624 (HFE-7500)
The photophysical properties of F-SubPCs are
summarized in Table 2 and Figs 2d–2f. In PhMe,
F-SubPC-2 and F-SubPC-3 were fluorescent, possessing
quantum yields of 25.1% and 35.2%, respectively. The
limited solubility of F-SubPC-1 in PhMe hindered
the determination of the quantum yield in PhMe. The
F-SubPCs dissolved in PFMCH also displayed a
broad absorbance in the visible region, with a small
hypsochromic shift. The F-SubPCs were only weakly
fluorescent in PFMCH (Figs 2a–2c), and the quantum
yields in PFMCH could not be determined.
elemental analysis. The low solubility of F-SubPC-1 in
deuterated solvents prevented the acquisition of NMR
characterization.
Properties of F-SubPCs
The F-SubPCs are consistently more soluble than their
F-PCs counterparts despite possessing nearly identical
wt% F. F-SubPC-1 was insoluble in common organic
solvents, but was facilely soluble in fluorous solvents
such as perfluoro(methylcyclohexane) (PFMCH), HFE-
-1
.
7500, and FC-770 (>1 mg mL ). F-SubPC-2 and
F-SubPC-2 displayed solubility in both organic
and fluorous phases to allow for comparisons, and in
fluorous solvents the intensity of longest wavelength
-1
.
F-SubPC-3 displayed moderate solubility (~1 mg mL )
in organic solvents such as chloroform and toluene
Copyright © World Scientific Publishing Company
J. Porphyrins Phthalocyanines

D
K. YOSHINAGA ET AL.
CnF2n+1
NC
R1
CN
R2
S
Cl
N
BCl3
N
N
B
1-3
S
p-Xylene
Reflux, 30 min
N
N
1: R1 = R2 =
2: R1 = R2 =
3: R1 = H, R2 =
C8F17
C6F13
S
N
S
S
S
C8F17
F2n+1Cn
CnF2n+1
F-SubPCs
Scheme 2. Synthesis of fluorous subphthalocyanines (F-SubPCs).
Fig. 2. Chemical structure and fluorous partition of (a) F-SubPC-1, (b) F-SubPC-2, and (c) F-SubPC-3. Absorbance and emission
spectra of (d) F-SubPC-1, (e) F-SubPC-2, and (f) F-SubPC-3.
Table 2. Summary of photophysical properties of F-SubPCs.
Compound
Fluorous partition
coefficient (PFMCH/
PhMe) (P)
l
abs, nm
Molar extinction
coefficient at labs
10 L mol cm )
–(PhMe)d
lem, nma
Quantum
Fluorescence
,
-1
yield j, %b
lifetime t1, nsc
-1
4
.
.
595 (PhMe)
606 (PhMe)
–(PhMe)d
–(PhMe)d
F-SubPC-1
36
580 (PFMCH) 1.46 (PFMCH)
595 (PhMe) 5.23 (PhMe)
586 (PFMCH) 2.00 (PFMCH)
581 (PhMe) 6.27 (PhMe)
587 (PFMCH) –(PFMCH)e
605(PhMe)
588 (PFMCH) –(PFMCH)e
594 (PhMe) 35.2 (PhMe) 2.87 (PhMe)
573 (PFMCH) –(PFMCH)e –(PFMCH)e
–(PFMCH)e
25.1 (PhMe) 2.72 (PhMe)
–(PFMCH)e
F-SubPC-2
F-SubPC-3
1.1
0.044
567 (PFMCH) –(PFMCH)d
b
c
aExcited at 500 nm. Measured with an integrating sphere excited at 500 nm. Referenced to 1,4-bis(5-phenyloxazol-2-yl)benzene (t1 = 1.32 ns,
MeOH). dNot measured due to low solubility. eNot measured due to weak fluorescence.
Copyright © World Scientific Publishing Company
J. Porphyrins Phthalocyanines

FLUOROUS PHTHALOCYANINES AND SUBPHTHALOCYANINES
E
band (labs ≈ 590 nm) decreased with a small increase
in the absorbance at ~540 nm. This is indicative of
H-aggregation in fluorous solvents, which is also likely
the cause of fluorescence quenching [26]. However, the
F-SubPCs can display fluorescence in fluorous solvents.
For instance, F-SubPC-1 is fluorescent in HFE-7500
and shows excellent partition in HFE-7500 over DEB
(Fig. S2).
magneto-optical effects in order to accommodate for
the solution-phase nature of the samples. Because
F-PCs displayed limited solubility in fluorous solvents,
the rotation spectra could not be obtained. Instead,
rotation spectra for F-PC-2 and F-PC-3 were obtained
in THF, displaying largest molar specific magnetic
6
-1
-1
.
T
-1
. .
rotations of -3.6 × 10 deg L mol
.
m and -8.8 ×
-1
-1
-1
105 deg L mol
. .
T m , respectively. Measurement
.
.
of F-PC-2 was conducted at elevated temperatures
due to its low solubility. For F-SubPCs, rotation
spectra were obtained in fluorous solvent PFMCH
for F-SubPC-1 and F-SubPC-2, and in organic
solvent PhMe for F-SubPC-2 and F-SubPC-3. The
comparison of the spectra for F-SubPC-2 enables the
study of the effect of organic and fluorous solvents on
Faraday rotation properties. While we see rotation
in fluorous solvent PFMCH (largest molar specific
Faraday rotation properties of F-PCs and F-SubPCs
The Faraday effect, discovered by Michael Faraday
two centuries ago, is a ubiquitous magneto-optical
effect, describing the rotation of the plane-polarized
light traveling through a material along the axis of an
applied magnetic field [27]. This effect is quantified by
a Verdet constant (V), which is wavelength dependent
and linearly correlated to the applied magnetic field and
the thickness of the material (Fig. 3). Recent emergence
of organic materials possessing high Verdet constants
such as semiconducting polymers [28, 29], mesogenic
organic molecules [30, 31] including phthalocyanines
[32, 33], and radical-containing polymers [34, 35] holds
promises in utilizing these materials in processable
devices. We have recently discovered that the role of
polymer conformation and supramolecular organization
affects the electronic delocalization and electromagnetic
interactions and thereby modulates the Faraday effect
[28, 34]. Because we observed H-aggregation of F-PCs
and F-SubPCs in fluorous solvents, we hypothesized that
the organization in fluorous solvents may give insight into
the origins of the Faraday effect, and affect the degree
of magnetic rotation. Thus, we sought to investigate the
Faraday rotation properties of F-PCs and F-SubPCs in
fluorous solvents.
4
-1
-1
-1
. .
.
.
magnetic rotation of -9.3 × 10 deg L mol
T m ), it
is lower in intensity than that in organic solvent PhMe
(largest molar specific magnetic rotation of -2.4 ×
5
-1
-1
-1
. .
.
.
T m ). Contrary to our expectations,
10 deg L mol
these results confirm that H-aggregation in fluorous
solvents was detrimental to the Faraday effect; however,
Faraday rotation properties measured in fluorous solvents
is unprecedented.
EXPERIMENTAL
General
All chemical reagents were purchased from Sigma–
Aldrich, Synquest Laboratories, Oakwood Chemicals,
Fluoryx Labs, or TCI, and used without purification
unless noted otherwise. Thin-layer chromatography
was performed with Baker-flex Silica Gel 1B-F plates
(JT Baker). Flash chromatography was performed
using technical grade silica gel with 60 Å pores and
230–400 mesh particle size (Sigma–Aldrich, 717185).
1H, 13C, and 19F nuclear magnetic resonance (NMR)
spectra were recorded on a JEOL model JNM-ECZ500R/
S1 spectrometer operating at 500, 126, and 471 MHz,
Fig. 4 summarizes the Faraday rotation properties
of F-PCs and F-SubPCs in various solvents (also see
Fig. S4 for experimental setup). An analog property
of the Verdet constant, the molar specific magnetic
-1
-1
-1
. .
rotation (deg L mol
.
.
T m ), was used to quantify
1
respectively. For H and 13C NMR spectra, deuterated
solvent references were used as internal standards (1H:
7.26 ppm for CDCl3, 2.05 ppm for acetone-d6; 13C:
77.16 ppm for CDCl3, 206.26 ppm for acetone-d6).
Multiplicities are abbreviated as singlet (s), doublet
(d), triplet (t) and multiplet (m). Direct analysis in real
time (DART) mass spectra and matrix-assisted laser
desorption/ionization time-of-flight (MALDI-TOF)
mass spectra were obtained at the MIT Department of
Chemistry Instrumentation Facility. Elemental analysis
data were obtained at Robertson Microlit Laboratories.
Fourier-transform infrared spectra were obtained on a
Thermo Scientific Nicolet 6700 FT-IR spectrometer.
UV-vis absorbance spectra were obtained on a Cary 4000
UV-vis spectrophotometer (Agilent Technologies) with a
Fig. 3. Schematic image of magneto-optical material displaying
a Faraday rotation. The degree of rotation (b) is governed by the
materials’ Verdet Constant (V), strength of magnetic field (B),
and the thickness of the material (d).
Copyright © World Scientific Publishing Company
J. Porphyrins Phthalocyanines

F
K. YOSHINAGA ET AL.
Fig. 4. Faraday rotation properties of F-PCs and F-SubPCs. Molar specific magnetic rotation of (a) F-PC-2 and (b) F-PC-3 in
THF. Molar specific magnetic rotation of (c) F-SubPC-1 and (d) F-SubPC-2 in PFMCH. Molar specific magnetic rotation of
(e) F-SubPC-2 and (f) F-SubPC-3 in PhMe. Spectra for F-PC-2 obtained by heating the solution to its boiling temperature (66°C).
scan rate of 600 nm.min-1. The instrument was blanked on
the solvent prior to obtaining a spectrum. Fluorescence
spectra were obtained on a Horiba Jobin Yvon SPEX
Fluorolog-t3 fluorimeter (model FL-321, 450 W Xenon
lamp). Quantum yields were determined by using
Horiba Quanta–j integrating sphere. Absorbance and
fluorescence data were collected in a quartz cuvette (1 cm
path length). Magneto-optical (MO) measurements were
performed using our custom Faraday rotation apparatus
(see Fig. S4 for experimental setup). Preparation of thin
films was unsuccessful, so various solutions of F-PCs
and F-SubPCs in organic and fluorous solvents were
measured in a quartz cuvette (0.05 cm path length). An
analog property of the Verdet constant, the molar specific
-1
-1
-1
. .
.
.
magnetic rotation (deg L mol
T m ), was used to
quantify MO effects in order to accommodate for the
solution-phase nature of the samples.
Synthesis
Compound 1. A mixture of 4,5-dichlorophthalonitrile
(98.5 mg, 0.500 mmol), 1H,1H,2H,2H-perfluorodeca-
nethiol (504 mg, 1.05 mmol), and anhydrous K2CO3
(400 mg, 2.89 mmol) in acetone (5 mL) was stirred at
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FLUOROUS PHTHALOCYANINES AND SUBPHTHALOCYANINES
G
60°C for 48 h. Then, 1M HCl aq (10 mL) was added
and the product precipitated. The precipitate was filtered
and collected, and was recrystallized from chloroform to
provide colorless crystals 1 (462 mg, 0.426 mmol, 85%
extraction with MeOH, CH2Cl2, and AcOEt for 24 h
each to obtain F-PC-1 as a dark green solid (114 mg,
0.0625 mmol, 41% yield). NMR and MALDI-TOF MS
spectra could not be obtained due to low solubility and
aggregation.ElementalAnal.calcd.forC112H40F136N8S8Zn
(%): C, 30.55; H, 0.92; N, 2.54. Found: C, 30.53; H, 1.03;
N, 3.23. UV-vis (THF): labs (log e) = 369 (4.9), 629 (4.7),
698 (5.2).
F-PC-2. F-PC-2 was synthesized by following a
method previously reported in the literature [21]. A
mixture of compound 2 (221 mg, 0.250 mmol), Zn(OAc)2
(12.8 mg, 0.0698 mmol), and 1,8-diazabicyclo[5.4.0]
undec-7-ene (DBU, 50 mL) in n-pentanol (5 mL)
was stirred at 140°C for 18 h. The reaction mixture
was cooled to room temperature and filtered. Further
purification was carried out by Soxhlet extraction with
MeOH, CH2Cl2, and AcOEt for 24 h each to obtain
F-PC-2 as a green solid (97.0 mg, 0.0269 mmol, 43%
yield). NMR spectra could not be obtained due to low
solubility and aggregation. MALDI-TOF MS: m/z
calcd. for C96H40F104N8S8Zn [M]+: 3599.8772. Found:
3599.8692. UV-vis (THF): labs (log e) = 366 (5.0), 627
(4.7), 697 (5.4). The characterization is consistent with
the previous literature report [21].
1
yield). H NMR (500 MHz; acetone-d6): d (ppm) 8.06
(s, 2H), 3.59 (t, J = 7.6 Hz, 4H), 2.68–2.84 (m, 4H). 13
NMR (126 MHz; acetone-d6): d (ppm) 143.70, 131.54,
116.43, 113.43, 31.10 (t, J = 22 Hz), 24.35. 19F NMR
(471 MHz; acetone-d6): d (ppm) -81.56 (t, J = 9.8 Hz,
6F), -114.23 (m, 4F), -122.14 (m, 4F), -122.37 (m, 8F),
-123.19 (m, 4F), -123.67 (m, 4F), -126.66 (m, 4F). DART
MS: m/z calcd. for [C28H10F34N2S2]+: 1083.9742. Found:
1083.9742.
C
Compound 2. Compound 2 was prepared by follo-
wing a method previously reported in the literature
[21]. A mixture of 4,5-dichlorophthalonitrile (197 mg,
1.00 mmol), 1H,1H,2H,2H-perfluorooctanethiol (849
mg, 2.23 mmol), and anhydrous K2CO3 (412 mg,
2.98 mmol) in acetone (5 mL) was stirred at 60°C for
48 h. Then, 1M HCl aq (10 mL) was added and the
product precipitated. The precipitate was filtered and
collected, and was recrystallized from chloroform to
provide colorless crystals 2 (789 mg, 0.892 mmol, 89%
1
yield). H NMR (500 MHz; acetone-d6): d (ppm) 8.04
(s, 2H), 3.58 (t, J = 7.6 Hz, 4H), 2.86–2.62 (m, 4H).
19F NMR (471 MHz, acetone-d6, 25°C): d (ppm) -81.62
(t, J = 9.8 Hz, 6F), -114.26 (m, 4F), -122.39 (m, 4F),
-123.39 (m, 4F), -123.74 (m, 4F), -126.73 (m, 4F).
The characterization is consistent with the previous
report [21].
F-PC-3. A mixture of compound 3 (152 mg,
0.251 mmol), Zn(OAc)2 (12.8 mg, 0.697 mmol), and
1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 50 mL) in
n-pentanol (5 mL) was stirred at 140°C for 18 h. The
reaction mixture was cooled to room temperature and
filtered. Further purification was carried out by Soxhlet
extraction with MeOH, CH2Cl2, and AcOEt for 24 h
each to obtain F-PC-3 as a teal-green solid (50.1 mg,
0.0201 mmol, 32% yield). NMR spectra could not be
obtained due to low solubility and aggregation. MALDI-
TOF MS: m/z calcd. for C72H28F68N8S4Zn [M + H]+:
2488.9604. Found: 2488.9574. Elemental Anal. calcd.
for C72H28F68N8S4Zn (%): C, 34.72; H, 1.13; N, 4.50.
Found: C, 35.00; H, 0.56; N, 4.87. UV-vis (THF): labs
(log e) = 357 (5.0), 616 (4.7), 683 (5.5).
F-SubPC-1. F-SubPC-1 was synthesized by following
a method previously reported in the literature [25].
Compound 1 (462 mg, 0.426 mmol) was added to a dried
flask, and BCl3 (1.0 M in p-xylene, 0.450 mL) was added
dropwisely. Then, the reaction mixture was stirred at
160°C in a pre-heated oil bath for 30 min. Upon cooling
the reaction mixture to room temperature, it was diluted
with FC-770 (5 mL) and transferred to a separation funnel.
The fluorous layer was washed with chloroform (10 mL),
acetone (10 mL), water, (10 mL), brine (10 mL), dried
with MgSO4, and evaporated to dryness under reduced
pressure. Further purification was carried out by Soxhlet
extraction with acetone for 72 h to obtain F-SubPC-1 as
a dark purple solid (63.2 mg, 0.0191 mmol, 13% yield).
NMR spectra could not be obtained due to low solubility
and aggregation. MALDI-TOF MS: m/z calcd. for
C84H30BClF102N6S6 [M]+: 3297.9009. Found: 3297.9106.
UV-vis (HFE-7500): labs (log e) = 359 (4.3), 592 (4.2).
Compound 3. A mixture of 4-fluorophthalonitrile
(294mg,2.01mmol),1H,1H,2H,2H-perfluorodecanethiol
(985 mg, 2.05 mmol), and anhydrous K2CO3 (400 mg,
2.89 mmol) in acetone (5 mL) was stirred at 60°C for
16 h. Then, 1M HCl aq (10 mL) was added and the
product precipitated. The precipitate was filtered and
collected, and dissolved in acetone. The acetone solution
was precipitated in excess hexanes, and the precipitate
was filtered and collected to provide 3 as a white solid
1
(980 mg, 1.62 mmol, 81% yield). H NMR (500 MHz;
acetone-d6): d (ppm) 8.06 (s, 1H), 7.98 (d, J = 8.4 Hz,
1H), 7.88 (d, J = 8.4 Hz, 1H), 3.56 (t, J = 7.8 Hz, 2H),
2.70–2.79 (m, 2H). 13C NMR (126 MHz; acetone-d6): d
(ppm) 146.08, 134.79, 131.94, 131.85, 117.15, 116.55,
116.20, 112.42, 31.22 (t, J = 22 Hz), 23.42. 19F NMR
(471 MHz; acetone-d6): d (ppm) -81.56 (t, J = 9.8 Hz,
3F), -114.36 (m, 2F), -122.14 (m, 2F), -122.35 (m, 4F),
-123.18 (m, 2F), -123.67 (m, 2F), -126.65 (m, 2F). DART
MS: m/z calcd. for C18H7F17N2S [M]+: 606.0058. Found:
606.0071, 607.0155 [M + H]+, 624.0422 [M + NH4]+,
665.0584 [M + acetone + H]+.
F-PC-1. A mixture of compound 1 (271 mg,
0.250 mmol), Zn(OAc)2 (12.8 mg, 0.0698 mmol), and
1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 50 mL) in
n-pentanol (5 mL) was stirred at 140°C for 18 h. The
reaction mixture was cooled to room temperature and
filtered. Further purification was carried out by Soxhlet
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J. Porphyrins Phthalocyanines

H
K. YOSHINAGA ET AL.
F-SubPC-2. Compound 2 (265 mg, 0.300 mmol)
was added to a dried flask, and BCl3 (1.0 M in p-xylene,
0.300 mL) was added dropwisely. Then, the reaction
mixture was stirred at 160°C in a pre-heated oil bath
for 30 min. Upon cooling the reaction mixture to room
temperature, it was diluted with FC-770 (5 mL) and
transferred to a separation funnel. The fluorous layer
was washed with chloroform (10 mL), acetone (10 mL),
water, (10 mL), brine (10 mL), dried with MgSO4, and
evaporated to dryness under reduced pressure. The
residue was chromatographed on silica gel using CHCl3
as an eluent, and the fraction containing F-SubPC-2
(Rf = 0.60) was collected and evaporated to dryness to
provide a dark purple solid (50.2 mg, 0.0185 mmol,
fluorous solvents showed different trends, suggestive of
H-aggregation in fluorous solvents. On the other hand,
the nonplanar F-SubPCs showed improved solubility in
fluorous solvents, and followed the trend of higher wt%
F displaying higher fluorous solubility. The F-SubPCs
were fluorescent in organic solvents and HFE-7500, but
were only weakly fluorescent in PFMCH, which is also
suggestive of H-aggregation. We have also studied the
Faraday rotation properties of F-PCs and F-SubPCs
in fluorous and organic solvents. The compounds
described in this report pave the way for the discovery
of functional fluorous soluble phthalocyanines and
subphthalocyanines. Further characterization of the
properties of F-PCs and F-SubPCs is underway, and we
anticipate these compounds will find applications as new
fluorous soluble/dispersible materials.
1
19% yield). H NMR (500 MHz; CDCl3): d (ppm) 8.76
(s, 6H), 3.38–3.49 (m, 12H), 2.49–2.64 (m, 12H). 19F
NMR (471 MHz; CDCl3): d (ppm) -80.79 (t, J = 9.8 Hz,
18F), -113.94 (m, 12F), -121.87 (m, 12F), -122.87 (m,
12F), -123.19 (m, 12F), -126.17 (m, 12F). MALDI-
TOF MS: m/z calcd. for C72H30BClF78N6S6 [M + H]+:
2698.9471. Found: 2698.9707. Elemental Anal. calcd.
for C72H30BClF78N6S6 (%): C, 32.03; H, 1.12; N, 3.11.
Found: C, 32.49; H, 1.03; N, 2.89. UV-vis (PhMe): labs
(log e) = 373 (4.2), 595 (4.7).
Acknowledgments
Financial support from the Air Force Office of
Scientific Research (FA9550-18-1-0341) and the
National Science Foundation (NSF) Center for Energy
Efficient Electronics Science (E3S) (Award ECCS-
0939514) is greatly appreciated. K.Y. thanks Funai
Overseas Scholarship for financial support.
F-SubPC-3. Compound 3 (300 mg, 0.495 mmol)
was added to a dried flask, and BCl3 (1.0 M in p-xylene,
0.500 mL) was added dropwisely. Then, the reaction
mixture was stirred at 160°C in a pre-heated oil bath
for 30 min. Upon cooling the reaction mixture to room
temperature, it was diluted with FC-770 (5 mL) and
transferred to a separation funnel. The fluorous layer
was washed with chloroform (10 mL), acetone (10 mL),
water, (10 mL), brine (10 mL), dried with MgSO4, and
evaporated to dryness under reduced pressure. The
residue was chromatographed on silica gel using CHCl3
as an eluent, and the fraction containing F-SubPC-3
(Rf = 0.60) was collected and evaporated to dryness to
provide a dark purple solid (90.0 mg, 0.0483 mmol,
29% yield). HPLC separation was unsuccessful. 1H
NMR (500 MHz; CDCl3): d (ppm) 8.76–8.83 (m, 6H),
7.85–7.89 (m, 3H), 3.35–3.48 (m, 6H), 2.48–2.59 (m,
6H). 19F NMR (471 MHz; CDCl3): d (ppm) -80.78–80.51
(m, 9F), -113.60 (m, 2F), -113.99 (m, 4F), -121.59 (m,
6F), -121.82 (m, 12F), -122.62 (m, 6F), -123.15 (m,
6F), -126.01 (m, 6F). MALDI-TOF MS: m/z calcd. for
C54H21BClF51N6S3 [M]+: 1863.9957. Found:1863.9942.
UV-vis absorbance (PhMe): labs (log e) = 358 (4.3),
581 (4.8).
Supporting information
Supplementary figures and spectral data (NMR,
MALDI TOF-MS) are given in the Supporting
information. This material is available free of charge via
the internet at http://worldscinet.com/jpp/jpp.shtml.
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