Synthesis and characterization of novel metal-free and metallo- porphyrazines with eight 3-thiopropylpentafluorobenzoate units

Article abstract of DOI:10.1016/j.poly.2012.03.015

Metal-free and metallo-porphyrazines (M = 2H, Mg, Cu, Zn or Co) with eight polyfluorinated groups appended on the periphery through flexible alkylthio-bridges have been synthesized through esterification of octakis(hydroxypropylthio)porphyrazinato magnesi

Full text of DOI:10.1016/j.poly.2012.03.015

Polyhedron 38 (2012) 218–223
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Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis and characterization of novel metal-free and metallo-porphyrazines
with eight 3-thiopropylpentafluorobenzoate units
⇑
Hakan Kunt, Ergün Gonca
Fatih University, Department of Chemistry, TR 34500 B.Cekmece, Istanbul, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Metal-free and metallo-porphyrazines (M = 2H, Mg, Cu, Zn or Co) with eight polyfluorinated groups
appended on the periphery through flexible alkylthio-bridges have been synthesized through esterifica-
tion of octakis(hydroxypropylthio)porphyrazinato magnesium with 2,3,4,5,6-pentafluorobenzoic acid in
the presence of dicyclohexylcarbodiimide (DCCI) and toluene-p-sulfonic acid. The symmetrically func-
tionalized porphyrazines with eight ester units are soluble in common organic solvents, such as CHCl3,
CH2Cl2, THF, acetone and toluene, and are insoluble in water and n-hexane. The newly synthesized com-
pounds were characterized by FT-IR, UV–Vis, mass, 1H, 13C and 19F NMR, together with elemental
analysis.
Received 28 December 2011
Accepted 5 March 2012
Available online 21 March 2012
Keywords:
Porphyrazine
Pentafluorobenzoic acid
Esterification
Magnesium
Cobalt
Ó 2012 Elsevier Ltd. All rights reserved.
Zinc
1. Introduction
[22], 3-methylbutylthio [23], 1-naphthylmethylthio [24], 9-anth-
racenylmethylthio [25], 3,5-bis-trifluoromethyl-benzylthio [26],
Tetrapyrrole macrocycles, such as phthalocyanines, porphyrines
and porphyrazines, possess a conjugated system of 18 -electrons.
The presence of a -electron system is essential for charge-carrier
etc.) on the peripheral positions of the porphyrazines has been
accomplished by either starting with an unsaturated dinitrile pre-
cursor or a preformed porphyrazine with reactive functional groups
that can be subsequently modified (e.g. crown ethers [27], ferro-
cenes [28], triphenylphosphine [29], acetoxy [30], etc. have been
incorporated by further condensation reactions).
p
p
transport, so they exhibit a number of unique properties which
attribute them great interest in several scientific and technological
areas ranging from nanotechnology to medicine [1–3]. There has
been growing interest in the use of tetrapyrrole macrocycles in a
variety of new high technology fields including energy conversion,
electrophotography, gas sensors, liquid crystals, infrared dyes for
laser technology, optical data storage, semiconductor devices,
Langmuire–Blodgett films, electrochromic display devices, non-lin-
ear optics, organic light emitting diodes (OLED), photodynamic
cancer therapy and various catalytic processes [4–14]. They have
also been of considerable interest to theoretical chemists owing
to their high symmetry, planarity, thermal stability and electronic
delocalization [15,16]. A significant amount of work has been car-
ried out on their magnetic and catalytic properties and also on
their role in biomolecular processes [17,18].
Solubility is an important property for porphyrazines and most
of their treatments are best determined in the soluble form. Because
the parent unsubstituted metal-free, metallo-porphyrazines and
most of the metal polymeric porphyrazine structures are less or
insoluble in common organic solvents, the synthesis of a new por-
phyrazine system should be essentially designed in such a way that
the final porphyrazine derivatives are sufficiently soluble to per-
form the desired activities. Compared to the unsubstituted parent
metal porphyrazines, ester-containing porphyrazines are highly
soluble in chlorinated hydrocarbons, such as dichloromethane and
chloroform [27–32]. A further step for porphyrazine esters is the
possibility of forming supramolecular structures with donor groups
on the ester moiety. The applications of ester-containing tetrapyr-
role compounds are very variable. For example, some esters [33]
showed a gas-sensor response against NOx gases, whereas some
showed characteristics of liquid crystals with glassy transitions
[34,35]. Furthermore, some patents and publications reported that
ester-containing tetrapyrroles could be used as tumor growth sup-
pressors [36], electro-photographic photoconductors [37], optical
storage agents [38] and photosensitizers in photo-dynamic therapy
[39,40].
During the last decade, intensive research interest on peripher-
ally functionalized porphyrazines has shown that these tetrapyrrole
derivatives should be considered as alternatives to phthalocyanines
[19]. Substitution of different various groups (e.g. 4-tert-buthylphe-
nylthio [20], o-tolylthio and p-tolylthio [21], tosylaminoethylthio
⇑
Corresponding author. Tel.: +90 212 866 33 00; fax: +90 212 866 34 02.
E-mail address: egonca@fatih.edu.tr (E. Gonca).
0277-5387/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2012.03.015

H. Kunt, E. Gonca / Polyhedron 38 (2012) 218–223
219
Metal phthalocyanines bearing fluorine atoms are currently
2.2. [2,3,7,8,12,13,17,18-Octakis(3-hydroxypropylthio)porphyrazina
to] Mg(II) (3)
receiving a great deal of attention due to their high thermal and
chemical stability, interesting electron-transporting characteris-
tics, hydrophobicity, lipophobicity and decreased intermolecular
attractive forces in comparison to their hydrocarbon analogs [41–
44]. It has been reported that the position and the number of pen-
tafluorophenyl groups on the macrocycle ring has a marked effect
on the stability and catalytic activity [45,46]. Placing stronger elec-
tron-withdrawing fluorine atoms on the Pc ring results in both the
valence and conduction band energies being further lowered. Thus,
MPcFn (n: number of fluorine atoms) exhibits n-type behavior,
while unsubstituted phthalocyanines possess p-type behavior
due to doping with electron-accepting molecules [47]. These unu-
sual properties of MPcFn have led scientists to expose their chem-
istry for use in a number of different industrial applications [48].
In the present work, the reactivity of hydroxypropylsulfanyl
groups of metal-free and metallo-porphyrazines, which are novel
compounds (4–8), has been demonstrated by the esterification
with carboxylate groups such as pentafluorobenzoic acid. They
are highly soluble redox-active compounds; therefore, they might
be used in catalytic applications. The novel compounds have been
characterized by FT-IR, UV–Vis, mass, 1H, 13C and 19F NMR, to-
gether with elemental analysis.
Mg turnings (6 mg, 0.25 mmol) and a small I2 crystal were re-
fluxed in n-BuOH (20.0 mL) for about 8 h to obtain Mg(BuO)2.
2,3-Bis(3-hydroxypropylthio)maleonitrile (2) (129 mg, 0.50 mmol)
was added to this solution and the mixture was refluxed for about
12 h. The resulting blue-green suspension was filtered while hot,
and the precipitate was washed with n-BuOH. The combined fil-
trates were evaporated and the residue was washed with aqueous
10% Na2CO3 solution (100 mL). The suspension was centrifuged
and washed with distilled H2O. The blue-green highly viscous
product was dissolved in MeOH, filtered, and finally the solvent
was evaporated in vacuum. Purification of the product was accom-
plished by column chromatography with silica gel using methanol/
chloroform (1:20) as the eluent. The colored product was soluble in
methanol, ethanol, n-propanol, DMF, DMSO and THF, but insoluble
in n-hexane. Yield: 95 mg (72%). FT-IR, m
max/(cmÀ1): 3330 (OH),
2955–2825 (CH, aliphatic), 1065 (CAO). 1H NMR (d, ppm): 4.55
(8H, t, OH), 4.38 (16H, t, OACH2), 3.66 (16H, t, SACH2), 2.48 (m,
16H, ACH2A). 13C NMR (d, ppm): 26.2, 29.6, 61.7, 115.5, 121.7.
MS (ESI) m/z: 1057.2 [M]+.
2.3. [2,3,7,8,12,13,17,18-Octakis(3-thiopropylpentafluorobenzoate)
2. Experimental
porphyrazinato] Mg(II) (4)
IR spectra were recorded on a Perkin Elmer Spectrum One FT-IR
(ATR sampling accessory) spectrophotometer, electronic spectra
on a Unicam UV2 spectrophotometer. Elemental analyses were
recorded on a Thermo Scientific 2000 instrument. 1H, 13C and 19F
NMR spectra were taken in CDCl3 solutions at 400.000, 100.577
and 376.308 MHz, respectively, recorded on a Bruker Ultra Shield
Plus 400 MHz spectrometer. Chemical shifts refer to TMS (1H and
13C NMR) and fluorotrichloromethane (19F NMR) as the internal
standards. By using the electrospray ionization (ESI) method, mass
spectra were recorded on a Bruker Daltonics Micro-TOF and
MALDI-TOF mass spectrometer. The instrument was operated in
the positive ion mode. All reactions were carried out under a
nitrogen atmosphere in dried solvents. All chemicals were used with
sufficient chemical purity. 2,3,4,5,6-Pentafluorobenzoic acid,
Octakis(3-thiopropylpentafluorobenzoate)porphyrazinato mag-
nesium (4) was prepared by the reaction of 3 (0.529 g, 0.5 mmol),
2,3,4,5,6-pentafluorobenzoic acid (2.545 g, 12 mmol), dicyclohex-
ylcarbodiimide (DCCI) (2.208 g, 12 mmol) and toluene-p-sulfonic
acid (0.086 g, 0.5 mmol) in dry pyridine (30 mL) under N2 at ambi-
ent temperature for 72 h. The suspension was filtered and the
solvent was evaporated in a vacuum. The residue was treated with
CHCl3 (100 mL) and the clear solution was extracted with 10%
Na2CO3 solution (100 mL) and then with distilled water. The
extraction was repeated several times with distilled water until
the pH was neutral. The chloroform phase was dried over anhy-
drous Na2SO4 and the solvent was evaporated in a vacuum. The
colored product was stirred in cold CH2Cl2, filtered and the solvent
was evaporated in a vacuum. The residue was treated with ace-
tone. The purification of the product was accomplished by column
chromatography (SiO2, CH3OH:CHCl3, 1:50 v/v). The colored prod-
uct was soluble in CHCl3, CH2Cl2, THF, acetone and toluene, and
insoluble in distilled water and n-hexane. Yield: 757 mg (58%).
3-chloro-1-propanol,
N,N-dicyclohexylcarbodiimide
(DCCI),
toluene-p-sulfonic acid, N,N-dimethylformamide, chloroform,
dichloromethane, pyridine, sodium sulfate and sodium carbonate
were purchased from Aldrich, Merck or Alfa Aesar. Silica gel 60
FT-IR,
m
max/(cmÀ1): 2940–2855 (CH, aliphatic), 1720 and 1255
(63–200 lm, Merck) was used for column chromatography. Analyt-
(COO), 1650 (C@C, aromatic), 1328, 1157, 1126, 628. 1H NMR (d,
ppm): 4.66 (16H, t, OACH2), 4.10 (16H, t, SACH2), 2.52 (m, 16H,
ACH2A). 13C NMR (d, ppm): 26.4, 29.9, 61.9, 110.2, 115.8, 121.9,
137.4, 146.8, 147.9, 166.2. 19F NMR (d, ppm): À142.6 (o-fluoro),
À152.8 (p-fluoro), À161.4 (m-fluoro). MS (ESI) m/z: 2610.8 [M]+.
ical thin-layer chromatography (TLC) was performed using Merck
60 F254 silica gel (precoated sheets, 0.2 mm thick). The disodium salt
of dithiomaleonitrile (1) was prepared according to the previously
reported procedures [49].
2.1. 2,3-Bis(3-hydroxypropylthio)maleonitrile (2)
2.4. [2,3,7,8,12,13,17,18-Octakis(3-thiopropylpentafluorobenzoate)
To a vigorously stirred suspension of the disodium salt of dithi-
omaleonitrile (5.59 g, 30.0 mmol) in abs. EtOH (250 mL) under N2,
a solution of ClCH2CH2CH2OH (5.67 g, 60.0 mmol) in abs. EtOH
(10 mL) was added dropwise. After stirring for 72 h, the mixture
was filtered and the filtrate was concentrated under vacuum. The
reddish-brown oily residue was extracted several times with anhy-
drous t-BuOMe and after evaporation of the solvent in vacuum, a
reddish-brown highly viscous product was obtained, which was
recrystallised from cold Et2O as white crystals. Yield: 5.81 g
H
21, H23 porphyrazine] (5)
Compound 4 (106 mg, 0.1 mmol) was dissolved in a minimum
amount of trifluoroaceticacid (ꢀ3.00 mL) and stirred for 3 h at
room temperature. The reaction mixture was then added to ice
dropwise and neutralized with 25% ammonia solution. Precipita-
tion occurred and this precipitate was filtered. The precipitate
was extracted into chloroform and the chloroform solution was
extracted with distilled water twice. After drying over anhydrous
Na2SO4, the solvent was evaporated to obtain a violet colored me-
tal-free porphyrazine. Compound 5 was obtained by column chro-
matography (SiO2, CH3OH:CHCl3, 1:50 v/v). Yield: 176 mg (68%).
(75%). FT-IR, m
max/(cmÀ1): 3350 br (OH), 2985–2883 (CH, aliphatic),
2227 (C„N), 1650 (C@C), 1055 (CAO). 1H NMR (d, ppm): 4.72 (2H,
t, OH), 3.61 (4H, t, OACH2), 3.27 (4H, t, SACH2), 2.42 (m, 4H,
ACH2A). 13C NMR (d, ppm): 26.4, 30.0, 62.2, 115.9, 122.2. MS
(ESI) m/z: 258.8 [M]+.
FT-IR,
and 1265 (COO), 1652 (C@C, aromatic), 1324, 1152, 1120, 622.
m
max/(cmÀ1): 3285 (NAH), 2985–2850 (CH, aliphatic), 1727

220
H. Kunt, E. Gonca / Polyhedron 38 (2012) 218–223
1H NMR (d, ppm): 4.44 (16H, t, OACH2), 4.15 (16H, t, SACH2), 2.55
(m, 16H, ACH2A), À1.55 (br s, 2H, NH). 13C NMR (d, ppm): 26.5,
29.8, 61.8, 109.8, 115.9, 121.7, 137.0, 146.5, 147.7, 165.9. 19F
NMR (d, ppm): À142.4 (o-fluoro), À151.2 (p-fluoro), À154.6 (m-flu-
oro). MS (ESI) m/z: 2587.2 [M]+.
3. Results and discussion
As proposed by Linstead, an unsaturated 1,2-dinitrile derivative
should be prepared as the starting material [49,50]. The disodium
salt of dithiomaleonitrile (1), obtained from the simple reactants
sodium cyanide and carbondisulfide in two steps, was referred to
as the starting point. Alkylation of the disodium salt of maleonitrile
with 3-chloro-1-propanol in absolute ethanol gave 2,3-bis
(3-hydroxypropylthio)maleonitrile (2), which was in the cis-form
and easily soluble in chloroform, dichloromethane and acetone
(Scheme 1). The reddish-brown colored product (2) was obtained
in 75% yield. The presence of bulky electron-donating S-groups is
expected to enhance the chemical stability and optical properties
of porphyrazines [51]. Octakis(3-hydroxypropylthio)porphyrazina-
to magnesium (3) is obtained by cyclotetramerization of 2,3-bis
(3-hydroxypropylthio)maleonitrile in a high-boiling solvent, like
n-butanol, at high temperatures for 12 h [52–54]. Under normal
conditions, the porphyrazine core has a À2 charge, so divalent me-
tal ions give neutral porphyrazine complexes. Compound 3 was
very soluble in most common solvents, such as methanol, ethanol,
n-propanol, DMF and DMSO, but insoluble in n-hexane (Scheme 1).
Octakis(3-thiopropylpentafluorobenzoate)porphyrazinato magne-
sium (4), with eight polyfluorinated groups appended on the
periphery through flexible alkylthio-bridges, has been synthesized
through esterification of 3 with 2,3,4,5,6-pentafluorobenzoic acid
in the presence of dicyclohexylcarbodiimide (DCCI) and toluene-
p-sulfonic acid.
The aim of the esterification was to enhance the overall solu-
bility in common organic solvents. The parent hydroxy-termi-
nated porphyrazines [55] are not practically soluble in solvents
like chloroform or tetrahydrofuran; therefore, in order to be used
more efficiently in some organic transformations or in some tech-
nological applications, these compounds must be converted into a
more soluble form. Ester groups are known to provide good solu-
bility, and they were selected because of the ease of their synthe-
sis [27–32]. The most efficient route for this condensation
reaction of carboxylic acid and the AOH groups on porphyrazines
was to carry out the reaction at room temperature in the presence
of a strongly dehydrating agent, such as dicyclohexylcarbodiimide
(DCCI). The by-product, dicyclohexylurea, was eliminated by
2.5. General procedure for metallo-porphyrazines (6–8)
Compound 5 (124 mg, 0.05 mmol) in CHCl3 (10.0 mL) was stir-
red with the metal salt [Cu(OAc)2 (91 mg, 0.5 mmol), Zn(OAc)2
(92 mg, 0.5 mmol) or Co(OAc)2 (89 mg, 0.5 mmol)] in ethanol
(15.0 mL) and refluxed under nitrogen for about 6 h. The precipi-
tate thus obtained was composed of the crude product and excess
metal salt. The precipitate was treated with CHCl3 and the insolu-
ble metal salts were removed by filtration. The filtrate was reduced
to a minimum volume under reduced pressure and then added to
n-hexane (150 mL) dropwise to ensure precipitation. Finally, the
pure porphyrazine derivatives (6–8) were obtained by the column
chromatography (SiO2, CH3OH:CHCl3, 1:20 v/v).
2.5.1. [2,3,7,8,12,13,17,18-Octakis(3-thiopropylpentafluorobenzoate)
porphyrazinato] Cu(II) (6)
Yield: 61 mg (46%). FT-IR,
m
max/(cmÀ1): 2980–2858 (CH, ali-
phatic), 1722 and 1262 (COO), 1648 (C@C, aromatic), 1320, 1155,
1122, 625. MS (ESI) m/z: 2649.8 [M]+.
2.5.2. [2,3,7,8,12,13,17,18-Octakis(3-thiopropylpentafluorobenzoate)
porphyrazinato] Zn(II) (7)
Yield: 72 mg (54%). FT-IR,
m
max/(cmÀ1): 2985–2855 (CH, ali-
phatic), 1720 and 1265 (COO), 1655 (C@C, aromatic), 1326, 1158,
1132, 621. 1H NMR (d, ppm): 4.64 (16H, t, OACH2), 4.12 (16H, t,
SACH2), 2.50 (m, 16H, ACH2A). 13C NMR (d, ppm): 26.6, 29.7,
61.8, 110.1, 115.9, 121.7, 137.1, 146.5, 147.4, 166.1. 19F NMR (d,
ppm): À142.9 (o-fluoro), À152.6 (p-fluoro), À161.6 (m-fluoro).
MS (ESI) m/z: 2651.9 [M]+.
2.5.3. [2,3,7,8,12,13,17,18-Octakis(3-thiopropylpentafluorobenzoate)
porphyrazinato] Co(II) (8)
Yield: 56 mg (42%). FT-IR,
m
max/(cmÀ1): 2986–2854 (CH, ali-
phatic), 1725 and 1260 (COO), 1648 (C@C, aromatic), 1316, 1165,
1135, 629. MS (ESI) m/z: 2644.2 [M]+.
NC
S
OH
OH
SNa
SNa
NC
(i)
(ii)
Cl
OH
+
NC
HO
NC
S
OH
O
H
OH
S
S
N
S
N
S
S
N
N
N
N
(iv)
(iii)
(v)
Mg
N
_ 8
N
4
5
6
S
S
S
OH
O
H
OH
O
H
Scheme 1. (i) Abs. EtOH; (ii) Mg turnings, I2, n-BuOH; (iii) 2,3,4,5,6-pentafluorobenzoic acid, DCCI, toluene-p-sulfonic acid and dry pyridine; (iv) CF3CO2H; (v) EtOH, CHCl3
and Cu(OAc)2, Zn(OAc)2, or Co(OAc)2.

H. Kunt, E. Gonca / Polyhedron 38 (2012) 218–223
221
Table 1
filtering the reaction mixture after treatment with cold dichloro-
Elemental analyses results of 2–8.*
methane. By referring to mass spectrometric data, the usage of
the DCCI-mediated esterification system for octakis(hydrox-
ypropylsulfanyl)porphyrazines ensured that all of the available
AOH groups reacted in the process. The choice of reaction time
was based on routine TLC tests and changed with different condi-
tions. Another aim of this study was to see the effect of different
esterification conditions on the reaction yield. Our results show
that the best condition was to utilize DCCI:OH group in a 9:1 M
ratio. Other procedures involved the usage of DCCI with tolu-
ene-p-sulfonic acid and the AOH group in a molar ratio like
24:1 [27–30,56,57]. The yield of 4 was of a sufficient level (58%)
(Scheme 1). The symmetrically functionalized porphyrazine with
eight ester units was soluble in common organic solvents, such
as CHCl3, CH2Cl2, THF, acetone and toluene, and insoluble in water
and n-hexane. The conversion of 4 into 5 was achieved by the
treatment with relatively strong acids (e.g. trifluoroacetic acid).
Further reaction of 5 with copper(II) acetate, zinc(II) acetate and
cobalt(II) acetate has led to the metal porphyrazinates (M = Cu,
Zn, Co) (6–8) (Fig. 1).
Compound
C
H
N
S
2
3
4
5
6
7
8
46.61 (46.49)
45.54 (45.42)
44.28 (44.17)
44.66 (44.55)
43.64 (43.52)
43.59 (43.49)
43.71 (43.60)
5.59 (5.46)
5.23 (5.34)
1.96 (1.85)
1.82 (1.95)
1.72 (1.83)
1.71 (1.82)
1.71 (1.83)
10.72 (10.84)
10.69 (10.59)
4.18 (4.29)
4.44 (4.33)
4.34 (4.23)
4.34 (4.23)
4.36 (4.24)
24.70 (24.82)
24.37 (24.25)
9.72 (9.83)
9.80 (9.91)
9.81 (9.68)
9.58 (9.68)
9.58 (9.70)
*
Required values are given in parentheses.
Comparison of the FT-IR spectra at each step gave some insights
on the nature of the compounds. The FT-IR spectrum of 3 provided
valuable information, as the C„N vibration at 2227 cmÀ1 disap-
pears with cyclotetramerization of 2. This peak can be used to
monitor the conversion, and to detect any ligand impurities in
the porphyrazine 3. In the FT-IR spectra for 4–8, aliphatic CAH
peaks around 2850–2986 cmÀ1
, C@O peaks around 1720–
1727 cmÀ1, OAC@O peaks at 1255–1265 cmÀ1, the aromatic C@C
peaks at 1648–1655 cmÀ1, the disappearance of the OAH peak
The newly synthesized compounds were characterized by FT-IR,
UV–Vis, mass, 1H, 13C and 19F NMR, together with elemental anal-
ysis. Spectral investigations for all new products were consistent
with the assigned structures. The elemental analyses corresponded
closely with the values calculated for 2–8 (Table 1).
around 3330 cmÀ1 for
3 and the NAH vibrations around
3285 cmÀ1 for 5, together with the high solubility in chloroform
and tetrahydrofuran acquired after this reaction, are all evidences
for the formation of 4–8.
F
F
F
F
F
F
F
F
O
F
O
F
F
F
F
F
F
F
O
O
F
F
F
O
O
F
O
O
S
S
N
S
S
S
N
N
N
N
N
M
N
S
F
O
F
N
F
O
F
F
S
S
O
O
F
F
F
F
F
O
O
F
F
F
O
O
F
F
F
F
F
F
F
M = Mg(4); 2H(5); Cu(6); Zn(7); Co(8).
Fig. 1. 2,3,7,8,12,13,17,18-Octakis(3-thiopropylpentafluorobenzoate) substituted porphyrazines (4–8).

222
H. Kunt, E. Gonca / Polyhedron 38 (2012) 218–223
The 1H NMR spectrum of 3 gave chemical shifts belonging to
changes in the nature of the solvent. As expected for a porphyr-
azine core (3), there are two intense absorptions: one of them is
in the UV-range around 368 nm and the other one is at the lower
energy side of the visible region (668 nm). In most tetrapyrrole
derivatives, the Q band absorption is more intense than the B band
OAH (triplet), OACH2 (triplet), SACH2 (triplet) and ACH2A (multi-
plet) at 4.55, 4.38, 3.66 and 2.48 ppm, respectively. In the 1H NMR
spectrum of 4, protons of the OACH2, SACH2 and ACH2A groups
come out around 4.66, 4.10 and 2.52 ppm, respectively. 1H NMR
spectrum of 5 showed a chemical shift belonging to the porphyr-
azine ring protons (singlet) at À1.55 ppm [27–30,56,57]. In the
13C NMR spectra of the diamagnetic porphyrazines 4, 5 and 7,
ten different single chemical shifts for carbon atoms were clearly
seen.
absorption, although both of them correspond to a
tion [52,60,61]. When we compare the absorbance values in these
p ?
p⁄ transi-
two peaks, the one in the UV-range is higher. The reason for this
controversy is the combination of
p–
p⁄ transitions of penta-
fluorobenzoate units with the B band of the porphyrazine core.
For the metal-free derivative (5), the Q band is split into two peaks
at 650 and 710 nm as a consequence of the change in the symme-
try of the porphyrazine core from D4h (in the case of the metallo
19F NMR spectroscopy has been a very useful technique for
investigating fluorinated compounds. The 19F NMR spectrum of 4
showed three different peaks at À142.6, À152.8 and À161.4 ppm,
relating to the fluorine atoms in the ortho, para and meta positions
of the phenyl substituents, respectively, and the spectrum showed
the expected signals for the five fluorine atoms attached to the aro-
matic ring [58,59]. Integration of the peaks gave a 2:1:2 ratio as
expected.
derivatives) to D2h
.
The aggregation treatment of porphyrazines in solution, which
can be followed effectually by absorption works, is a good explana-
tion of the interactions between the aromatic macrocycles of the
porphyrazines. Aggregation, which is usually indicated as a copla-
nar association, is affected by the concentration, nature of the sol-
vent, nature of the substituents, complexed metal ions and
temperature [62–64]. The aggregation behavior of 6 was searched
at several concentrations in chloroform (Fig. 4). In chloroform, as
the concentration was increased, the intensity of the Q-band
In addition to these supportive results for the structures, mass
spectrometry results of the pentafluorobenzoate substituted mag-
nesium, metal-free, copper, zinc and cobalt porphyrazines (4–8)
confirmed the complete esterification of AOH groups by the pres-
ence of molecular ion peaks, at m/z: 2610.8 [M]+, 2587.2 [M]+,
2649.8 [M]+, 2651.9 [M]+ and 2644.2 [M]+, respectively.
UV–Vis spectra of 3, 4, 6–8 (Table 2) show two sharp bands as a
result of
p ?
p⁄ transitions of the macrocycles. The one around
300–400 nm is called the ‘‘B’’ or Soret band, while the one at
600–700 nm is called the ‘‘Q’’ band. The presence of an electron
donating group on the periphery causes a bathochromic shift of
the Q bands (4, 6–8). These two bands are present in all the kinds
of porphyrazine (3, 4, 6–8). UV–Vis spectra of 4, 6–8 in chloroform
are shown in Fig. 2. The UV–Vis spectra of 3 in solvents of different
polarity (chloroform, ethanol, dichloromethane and pyridine) are
given in Fig. 3. There is almost no difference with respect to the
Table 2
UV–Vis data for the porphyrazines 3–8 in chloroform.
Compound
k/nm (loge )
/dm3 molÀ1 cmÀ1
3
4
5
6
7
8
368 (4.94)
379 (4.65)
338 (4.85)
340 (4.95)
352 (4.93)
345 (4.65)
668 (4.79)
675 (4.91)
650 (4.65)
679 (4.99)
683 (4.97)
676 (4.72)
710 (4.68)
Fig. 3. UV–Vis spectra of 3 in various solvents.
Fig. 2. UV–Vis spectra of 4, 6–8 in chloroform.
Fig. 4. UV–Vis spectra of 6 in chloroform at different concentrations.

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223
absorption increased in parallel, and there were no new bands be-
cause of the aggregated species [23]. It is seen that the Beer–Lam-
bert law was obeyed for compound 6 for concentrations ranging
from 2 Â 10À5 to 5 Â 10À6 mol dmÀ3 (Fig. 4).
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4. Conclusions
_
_
In conclusion, this study shows that a poorly soluble porphyr-
azine derivative containing reactive groups can be used as a frame-
work for subsequent reactions, such as esterification. We believe
that some of the synthesized compounds might be utilized as cat-
alysts, soluble dyes and optical recording agents. Meanwhile, fluo-
rinated metallo porphyrazines have currently been receiving a
great deal of attention due to their interesting electron transport
characteristics. Also, fluorocarbons display enhanced hydrophobic-
ity, chemical resistance, thermal stability and lipophobicity in
comparison to their hydrocarbon counterparts. Therefore, the
products can be candidated for use in these areas.
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Acknowledgement
This work was supported by the Scientific Research Fund of Fa-
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