Synthesis and characterization of new soluble fluorinated seco-porphyrazines

Article abstract of DOI:10.1016/j.poly.2011.01.003

Magnesium porphyrazinate substituted with eight 3,5-bis(trifluoromethyl) phenyl groups on the peripheral positions has been synthesized by the cyclotetramerization of 3,4-[3,5-bis(trifluoromethyl)phenyl]pyrroline-2,5- diimine in the presence of magnesium butanolate. Acid-mediated demetallation of the magnesium porphyrazine resulted in peripheral oxidation of one pyrrole ring to reveal the seco-porphyrazine, octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco- porphyrazine-2,3-dione. Further reaction of this product with copper (II) acetate, zinc (II) acetate and cobalt (II) acetate has led to the metallo-derivatives, {octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-2,3- dioxoporphyrazinato} M(II) [M = Cu(II), Zn(II), Co(II)]. These new soluble complexes were characterized by elemental analysis, together with FT-IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR, UV-Vis and mass spectral data.

Full text of DOI:10.1016/j.poly.2011.01.003

Polyhedron 30 (2011) 1035–1039
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis and characterization of new soluble fluorinated seco-porphyrazines
⇑
Murat Altunkaya, Ergün Gonca
Department of Chemistry, Fatih University, TR34500 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:
Received 4 October 2010
Available online 18 January 2011
Magnesium porphyrazinate substituted with eight 3,5-bis(trifluoromethyl)phenyl groups on the
peripheral positions has been synthesized by the cyclotetramerization of 3,4-[3,5-bis(trifluoromethyl)-
phenyl]pyrroline-2,5-diimine in the presence of magnesium butanolate. Acid-mediated demetallation
of the magnesium porphyrazine resulted in peripheral oxidation of one pyrrole ring to reveal the seco-
porphyrazine, octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-porphyrazine-2,3-dione. Further reaction
of this product with copper (II) acetate, zinc (II) acetate and cobalt (II) acetate has led to the metallo-
derivatives, {octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-2,3-dioxoporphyrazinato} M(II) [M = Cu(II),
Zn(II), Co(II)]. These new soluble complexes were characterized by elemental analysis, together with
FT-IR, 1H NMR, 13C NMR, 19F NMR, UV–Vis and mass spectral data.
Keywords:
3,5-Bis(trifluoromethyl)phenyl
Seco-porphyrazine
Pyrroline
19F NMR spectroscopy
Magnesium
Ó 2011 Elsevier Ltd. All rights reserved.
Copper
1. Introduction
In comparison to their phthalocyanine counterparts, porphyra-
zines also often display a vastly increased solubility in organic
Porphyrins, phthalocyanines, tetrabenzoporphyrins and por-
phyrazines are tetrapyrrole macrocycle ring systems. These com-
plexes have been used in catalysis, photodynamic therapy of
tumors, electrophotography, optical data storage, security printing,
liquid crystals and as pigments and dyes [1–5]. Porphyrazines as a
chemical class similar to phthalocyanines provide the dominant
blue and blue-green pigments, due to their intense absorption at
long wavelengths in the visible spectrum together with their excel-
lent durability and relatively low cost, and their structural analogs
belong to a broad class of macroheterocyclic tetrapyrrole systems
that are constitutionally tetraaza analogs of porphyrins. These por-
phyrins are of considerable interest because their representatives
are components of the most important natural compounds (hemo-
globin, myoglobin, cytochromes, chlorophylls and others) and are
involved in vital processes including photosynthesis, cell respira-
tion and electron transport [6–10].
Recently, heteroatomic substitutions directly fused to the mac-
rocyclic periphery have brought increasing attention to porphyr-
azine studies. The relative ease of their synthetic preparation and
also the strong correlation between the nature of the substituent
and the electronic and optical properties of the macrocyclic ring
system play roles in this recent interest. Direct fusion of hetero-
atomic substituents onto the porphyrazine b-positions is possible.
To the best of our knowledge, there are no such examples for por-
phyrin derivatives [11–15].
solvents. Thus, they maintain a unique position among the tetra-
pyrrolic macrocycles, and their straightforward synthesis coupled
with their tuneable electronic and optical properties renders them
exciting candidates for a whole range of applications [16].
Our group has been heavily interested in the preparation of no-
vel soluble porphyrazine derivatives. Among these, Pzs with
peripheral functional groups such as quaternizable amino groups
[17], crown ethers [18], ferrocenes [19], pyridine [20], triphenyl-
phosphine [21], 4-tert-buthylphenylthio [22], o-tolylthio and p-
tolylthio [23], tosylaminoethylthio [24], 3-methylbutylthio [25]
and 3,5-bis-trifluoromethyl-benzylthio [26] can be cited. We have
also reported new porphyrazines with bulky electron rich substit-
uents such as 1-naphthylmethylthio [27] and 9-anthracenylmeth-
ylthio [28] units, with the aim of carrying out photoemission
studies. Recently, we have synthesized novel seco-porphyrazines
substituted with 1-naphthyl [29], o-tolyl and p-tolyl [30], 4-tert-
butylphenyl [31] and 4-biphenyl groups [32] on the peripheral
positions, as encountered by Barrett, Hoffman and coworkers with
peripheral amino derivatives [33].
Fluorinated metallo-tetrapyrrol compounds form a class of
coordination compounds which have currently been receiving a
great deal of attention due to their interesting electron transport
characteristics [34–36]. Also, fluorocarbons display enhanced
hydrophobicity, chemical resistance, thermal stability and lipop-
hobicity in comparison to their hydrocarbon counterparts [37,38].
At the beginning, the aim and scope of this work was to synthe-
size metallo-porphyrazinates substituted directly with eight 3,5-
bis(trifluoromethyl)phenyl groups on the peripheral positions.
Although the first step of this process to obtain magnesium
⇑
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 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2011.01.003

1036
M. Altunkaya, E. Gonca / Polyhedron 30 (2011) 1035–1039
porphyrazinate (3a) has been actualized in the requested direction,
demetallation to the metal-free compound led to an oxidized
seco-porphyrazine (3b), as encountered by Nie et al. [39] with
peripheral amino derivatives. Together with further metallated
products (3c–e), these new soluble complexes were characterized
by elemental analysis, together with FT-IR, 1H NMR, 13C NMR, 19F
NMR, UV–Vis and mass spectral data.
122.4, 124.7, 125.4, 125.9, 131.3, 133.0, 162.3. MS (ESI) (m/z):
519.8 [M]+.
2.3. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]
porphyrazinato} Mg(II) (3a)
Mg turnings (6 mg, 0.25 mmol) and a small amount of I2 crys-
tals were refluxed in n-BuOH (20 ml) for about 8 h to obtain
Mg(BuO)2. 3,4-[3,5-Bis(trifluoromethyl)phenyl]pyrroline-2,5-dii-
mine (260 mg, 0.5 mmol) was added to this solution and the mix-
ture was refluxed for about 12 h. The blue-green colored product
was filtered, washed with ethanol and water, and dried in vacuo.
The crude product was dissolved in CHCl3 and filtered. The CHCl3
solution was dried over anhydrous Na2SO4. When the solvent
was evaporated, the product was obtained. Finally, the pure por-
phyrazine was obtained by column chromatography (SiO2, CH3OH:
CHCl3, 1:50 v/v). The product was very soluble in chloroform, sol-
uble in dichloromethane and acetone, but insoluble in n-hexane.
2. Experimental
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 Finnigan Flash EA 1112 instrument.
1H NMR, 13C NMR and 19F NMR spectra, taken in CDCl3 solutions
at 400, 100.577 and 376.308 MHz, respectively, were recorded on
a Bruker Ultra Shield Plus 400 MHz spectrometer. Chemical shifts
refer to TMS (1H NMR and 13C NMR) and fluorotrichloromethane
19F NMR) as internal standards. Mass spectra were recorded on
Yield: 198 mg (78%). FT-IR,
m
max/(cmÀ1): 3070–3035 (CH, aro-
(
matic), 1662, 1608 (C@C, aromatic), 1575, 1513, 1465, 1382,
1338, 1275, 1165, 1115, 1056, 933, 904, 840, 705, 675, 583. 1H
NMR (d, ppm): 7.54 (s, 16H, Ar-H), 7.30 (s, 8H, Ar-H). 13C NMR (d,
ppm): 118.5, 121.8, 122.4, 124.9, 126.2, 131.4, 135.2. 19F NMR (d,
ppm): À63.46. MS (ESI) (m/z): 2033.8 [M]+.
a Bruker Daltonics Micro-TOF and MALDI-TOF mass spectrometers
using the electrospray ionization (ESI) method. The instrument
was operated in positive ion mode. All starting materials were pur-
chased from major suppliers and were used without any further
purification. The homogeneity of the products was tested in each
step by TLC.
2.4. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]-2-
seco-porphyrazine-2,3-dione} (3b)
2.1. Synthesis of 1,2-bis[3,5-bis(trifluoromethyl)phenyl]dinitrile
derivatives (1)
3a (203 mg, 0.1 mmol) was dissolved a the minimum amount of
trifluoroaceticacid (ꢀ4.00 ml) and stirred for 3 h at room tempera-
ture. When the reaction mixture was added to ice, drop by drop,
and neutralized with a 25% ammonia solution, precipitation oc-
curred and the mixture was filtered. The precipitate was extracted
into the chloroform, and the chloroform solution was extracted
with water twice. After drying over anhydrous Na2SO4, the solvent
was evaporated to obtain a violet colored metal-free porphyrazine.
3b was obtained by column chromatography (SiO2, CH3OH:CHCl3,
3,5-Bis(trifluoromethyl)phenylacetonitrile (3.18 g, 12.56 mmol)
and iodine (3.19 g, 12.56 mmol) in 1:1 Et2O–MeOH (30 ml) were
allowed to reflux under nitrogen for 1 h. The solution was cooled
to room temperature, then sodium methoxide (2.2 equiv, 2.0 M,
14 ml) – methanol solution was added drop by drop (over a period
of 30 min) into the reaction medium under a nitrogen atmosphere.
The reaction mixture was stirred for another 4 h. During this time,
more and more precipitation formed in the solution. The solution
was filtered at room temperature and the solid product was
washed with water. The product was a mixture of maleonitrile
and fumaronitrile derivatives. The product was brown colored
and was very soluble in chloroform, dichloromethane and acetone,
1:30 v/v). Yield: 133 mg (65%). FT-IR, m
max/(cmÀ1): 3333 (NAH),
3070–3030 (CH, aromatic), 1717 (C@O), 1660, 1612 (C@C, aro-
matic), 1582, 1506, 1410, 1346, 1306, 1275, 1188, 1126, 1068,
904, 846, 702, 688, 584. 1H NMR (d, ppm): 7.66 (s, 16H, Ar-H),
7.33 (s, 8H, Ar-H), À1.05 (br s, 2H, NH). 13C NMR (d, ppm): 118.6,
121.6, 122.5, 124.7, 126.0, 131.0, 135.4. 19F NMR (d, ppm):
À63.40. MS (ESI): (m/z): 2043.7 [M]+.
but insoluble in n-hexane. The yield was 1.42 g (45%). FT-IR, mmax
/
(cmÀ1): 3062–3026 (CH, aromatic), 2214 (C„N), 1660, 1612 (C@C,
aromatic), 1571, 1510, 1463, 1379, 1340, 1272, 1161, 1119, 1059,
938, 900, 842, 708, 679, 586. 1H NMR (d, ppm): 7.64 (s, 4H, Ar-
H), 7.38 (s, 2H, Ar-H). 13C NMR (d, ppm): 118.2, 121.5, 122.1,
124.6, 125.9, 131.0, 134.7. MS (ESI) (m/z): 502.9 [M]+.
2.5. General procedure for metallo seco-porphyrazines (3c–e)
3b (204 mg, 0.1 mmol) in CHCl3 (10 ml) was stirred with the
metal salt [Cu(OAc)2 (182 mg, 1 mmol), Zn(OAc)2 (183 mg,
1 mmol) or Co(OAc)2 (177 mg, 1 mmol)] in ethanol (15 ml) and re-
fluxed under nitrogen for about 4 h. The precipitate, composed of
the crude product and the excess metal salt, was then filtered.
The precipitate was treated with CHCl3 and the insoluble metal
salts were removed by filtration. The filtrate was reduced to a
minimum volume under reduced pressure and then added into
n-hexane (100 ml) drop by drop to realize the precipitation. Final-
ly, the pure porphyrazine derivatives (3c–e) were obtained by
column chromatography (SiO2, CH3OH: CHCl3, 1:100 v/v).
2.2. Synthesis of 3,4-[3,5-bis(trifluoromethyl)phenyl]pyrroline-2,5-
diimine (2)
1 (0.76 g, 1.51 mmol) was suspended in ethylene glycol (30 ml)
and heated to 115 °C. A small chunk of Na (12 mg) was added to
the reaction. When the temperature of the suspension reached
115 °C, gaseous NH3 was bubbled through the suspension for
1.5 h. The solution was filtered hot and the filtrate was poured over
ice water (200 ml). The precipitate was extracted with CHCl3, dried
(Na2SO4), and the solvent was removed under vacuum. The prod-
uct was isolated as a yellow-brown powder. Yield: 0.30 g (38%).
The unreacted fumaronitrile that was filtered from the ethylene
glycol reaction was dried and reused for the same reaction. FT-IR,
2.5.1. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]-2-
seco-2,3-dioxoporphyrazinato} Cu(II) (3c)
m
max/(cmÀ1): 3301 (NAH), 3065–3030 (CH, aromatic), 1664, 1610
Yield: 147 mg (70%). FT-IR, m
max/(cmÀ1): 3075–3035 (CH, aro-
(C@C, aromatic), 1575, 1512, 1465, 1380, 1342, 1270, 1164, 1121,
1061, 941, 905, 845, 706, 675, 583. 1H NMR (d, ppm): 7.59 (s, 4H,
Ar-H), 7.33 (s, 2H, Ar-H), 4.84 (br s, 3H, NH). 13C NMR (d, ppm):
matic), 1720 (C@O), 1662, 1610 (C@C, aromatic), 1584, 1508,
1412, 1344, 1308, 1271, 1185, 1122, 1070, 906, 842, 700, 689,
585. MS (ESI) (m/z): 2104.1 [M]+.

M. Altunkaya, E. Gonca / Polyhedron 30 (2011) 1035–1039
F C
1037
3
CF
3
F C
3
CN
CN
NC
CN
(i)
(ii)
F C
3
CF
F C
3
3
+
F C
3
CN
F C
3
F C
3
F C
3
F C
CF
3
3
F C
CF
3
3
(iv)
(v)
(iii)
(3a)
(3b)
(3c 3e)
HN
NH
N
H
Scheme 1. Et2O–MeOH, I2; (ii) ethylene glycol; (iii) Mg turnings, I2, n-BuOH; (iv) CF3CO2H; (v) EtOH and Cu(OAc)2, Zn(OAc)2 or Co(OAc)2.
2.5.2. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]-2-
1416, 1348, 1302, 1274, 1188, 1126, 1071, 905, 844, 703, 686,
seco-2,3-dioxoporphyrazinato} Zn(II) (3d)
582. MS (ESI): (m/z) 2099.2 [M]+.
Yield: 139 mg (66%). FT-IR, m
max/(cmÀ1): 3065–3030 (CH, aro-
matic), 1722 (C@O), 1664, 1608 (C@C, aromatic), 1584, 1504,
1406, 1348, 1305, 1274, 1180, 1124, 1069, 901, 844, 701, 689,
585. 1H NMR (d, ppm): 7.56 (s, 16H, Ar-H), 7.32 (s, 8H, Ar-H). 13C
NMR (d, ppm): 118.3, 121.6, 122.5, 124.8, 126.3, 131.6, 135.4. 19F
NMR (d, ppm): À63.35. MS (ESI) (m/z): 2106.8 [M]+.
3. Results and discussion
The starting point for a new porphyrazine structure with eight
[3,5-bis(trifluoromethyl)phenyl] groups bound to the periphery is
1,2-bis[3,5-bis(trifluoromethyl)phenyl]dinitrile (1), which was ob-
tained by oxidative coupling of 3,5-bis(trifluoromethyl)phenylace-
tonitrile in the presence of I2 [40]. The solid product (1) was
obtained in a yield of 45%. It was a mixture of maleo- and fumar-
onitriles, and the former was present in a negligible amount, as
2.5.3. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]-2-
seco-2,3-dioxoporphyrazinato} Co(II) (3e)
Yield: 155 mg (74%). FT-IR,
matic), 1718 (C@O), 1660, 1612 (C@C, aromatic), 1580, 1510,
m
max/(cmÀ1): 3072–3030 (CH, aro-
CF
F C
3
3
CF3
F3C
F C
3
CF
F3C
3
CF3
F3
C
CF
3
F
C
CF
3
3
N
N
N
N
N
N
N
N
O
O
F3
F3
C
F
C
CF
3
N
M
N
3
N
CF
CF3
N
3
M
N
N
CF
C
3
F3
C
N
N
F3
C
CF
F
3C
3
CF3
CF
F C
3
CF3
3
F
C
3
F C
CF
3
3
F3C
CF
3
M= Mg(3a)
M = 2H(3b); Cu(3c); Zn(3d); Co(3e)
Fig. 1. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]porfirazinato}-
Mg(II) (3a).
Fig.
2. {2,3,7,8,12,13,17,18-Octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-por-
phyrazine-2,3-dione} and metal derivatives [M = 2H, Cu(II), Zn(II) or Co(II)] (3b–e).

1038
M. Altunkaya, E. Gonca / Polyhedron 30 (2011) 1035–1039
Fig. 3. Mass spectra of 3a and 3b.
expected due to the presence of the 3,5-bis(trifluoromethyl)phenyl
substituents. Its reluctance to turn into the porphyrazine under the
usual conditions (i.e., Mg(OBu)2 in refluxing butanol) points out the
lower ratio of the maleonitrile component. This problem was
solved by reacting the fumaronitrile derivative with the corre-
sponding pyrroline derivative (2), which can be converted into
the macrocyclic porphyrazine quite easily at the reflux tempera-
ture of butanol [41]. Conversion of 3,4-[3,5-bis(trifluoro-
methyl)phenyl]pyrroline-2,5-diimine (2) into porphyrazine (3a)
was achieved by the template effect of magnesium butanolate
(Scheme 1). Cyclotetramerization gave the blue-green colored oc-
takis[3,5-bis(trifluoromethyl)phenyl] porphyrazinatomagnesium
(3a) (Fig. 1) in yield 78%. It is soluble in chloroform, dichlorometh-
ane and acetone, but insoluble in apolar hydrocarbon solvents,
such as n-hexane.
In the FT-IR spectrum of 1,2-bis[3,5-bis(trifluoromethyl)-
phenyl]dinitrile (1), the aromatic CAH peaks are around 3062–
3026 cmÀ1
, the stretching vibration of C„N is observed at
2214 cmÀ1, the aromatic C@C peak is at 1612 cmÀ1 and the stretch-
ing vibrations of CAF are at 1340, 1161 and 1119 cmÀ1. In the FT-IR
spectrum of 3,4-[3,5-bis(trifluoromethyl)phenyl]pyrroline-2,5-dii-
mine (2), the stretching vibration of NAH is observed at
3301 cmÀ1, the aromatic CAH peaks are around 3065–3030 cmÀ1
and the characteristic substituted ArACF3 peaks are at 1342,
1164 and 1121 cmÀ1. After conversion of 3,4-[3,5-bis(trifluoro-
methyl)phenyl]pyrroline-2,5-diimine (2) to porphyrazine 3a, the
NAH vibration at 3301 cmÀ1 disappeared. These values comply
with those reported in the literature for similar compounds
[29–32]. The NAH stretching absorption of the inner core of the
metal-free porphyrazine (3b) was observed around 3333 cmÀ1
,
In the conversion of 3a into 3b (Fig. 2) by treatment with rela-
tively strong acids (e.g., trifluoroacetic acid), a seco-porphyrazine
type macrocycle in which one of the four pyrrole rings has been
oxidized is the main product. Formation of oxidized species was al-
most inevitable even when the reaction was carried under inert
conditions. The 3,5-bis(trifluoromethyl)phenyl groups are not
comparable with dimethylamino groups [15,33,39], but are com-
parable with (p-tolyl) and (o-tolyl) groups as electron donors to
and also during acid-mediated demetallation of the magnesium
porphyrazine (3a) peripheral oxidation of one pyrrole ring was
confirmed with an intense absorption in the range 1717–
1722 cmÀ1 [33,39]. FT-IR spectra of all the porphyrazines
derivatives (3a–e) showed the aromatic CAH peaks are around
3075–3030 cmÀ1, the aromatic C@C peak is in the range 1664–
1608 cmÀ1 and the characteristic substituted ArACF3 peaks are at
1340, 1160, 1120 cmÀ1 [29–32].
the 18-
p
electron system of the inner core [30]. The tendency of
The NAH protons of the metal-free porphyrazine (3b) were also
identified in the 1H NMR spectrum, with a broad singlet peak at
d = À1.05 ppm presenting the typical shielding of the inner core
protons, which is a common feature of the 1H NMR spectra of
metal-free porphyrazines [17–19,24,27,42]. In the 1H NMR spectra
of the diamagnetic porphyrazines (3a, 3b and 3d), two different
types of protons are clearly seen as two singlets around 7.32–
7.66 ppm, corresponding to aromatic protons. In the 13C NMR spec-
tra of the diamagnetic porphyrazines (3a, 3b and 3d), seven
3,5-bis(trifluoromethyl)phenyl substituted porphyrazines to oxi-
dize to seco-porphyrazine derivatives should be higher than for
dimethylamino substituted ones because the reactions were car-
ried out under inert atmospheres during these experiments, yet
no product corresponding to the metal-free derivative of 3a could
be isolated. The mass spectral results have clearly indicated the
change of the structure from the magnesium porphyrazinate (3a)
to the demetallated seco-porphyrazine (3b) (Fig. 3). In addition to
the mass spectral results, the intense C@O absorption peaks clearly
differentiates the oxidized products from the symmetrically
octakis(3,5-bis(trifluoromethyl)phenyl) substituted magnesium
porphyrazinate. The metallation reactions of the demetallated
seco-porphyrazine (3b) with Cu(II), Zn(II) and Co(II) salts gave the
metallated species (3c–e).
All the products were identified through several spectroscopic
techniques such as FT-IR, 1H NMR, 19F NMR, 13C NMR, UV–Vis,
mass and elemental analysis. The spectroscopic data of the desired
products were in accordance with the assigned structures. The ele-
mental analyses results correspond closely with the calculated val-
ues for the products (Table 1).
Table 1
Elemental analyses results of the porphyrazinesa.
Compound
C
H
N
1
2
47.71 (47.83)
46.38 (46.26)
47.38 (47.26)
47.15 (47.03)
45.79 (45.66)
45.75 (45.62)
45.76 (45.76)
1.31 (1.20)
1.62 (1.75)
1.30 (1.19)
1.16 (1.28)
1.02 (1.15)
1.01 (1.15)
1.26 (1.15)
5.69 (5.58)
8.21 (8.09)
5.40 (5.51)
5.60 (5.48)
5.46 (5.32)
5.42 (5.32)
5.21 (5.34)
3a
3b
3c
3d
3e
a
Required values are given in parentheses.

M. Altunkaya, E. Gonca / Polyhedron 30 (2011) 1035–1039
1039
Table 2
around 676–684 nm and B bands in the near UV region around
340–352 nm (Table 2). For the metal-free derivative 3b, the Q band
is split into two peaks at 652 and 712 nm, as a consequence of the
change in the symmetry of porphyrazine core from D4h to C2v. The
UV–Vis spectra of 3a–e in chloroform are shown in Fig. 4. The elec-
tronic spectra of 3c taken at concentrations from 2 Â 10À5 to
5 Â 10À6 M show that no aggregation occurs in this concentration
range due to the peripheral [3,5-bis(trifluoromethyl)phenyl] sub-
stituents (Fig. 5).
UV–Vis data for the porphyrazines in chloroform.
Compound
k/nm (log e )
/dm3 molÀ1 cmÀ1
3a
3b
3c
3d
3e
344 (4.89)
336 (4.87)
340 (4.95)
352 (4.94)
350 (4.93)
676 (4.93)
652 (4.61)
680 (4.99)
684 (4.99)
682 (4.99)
712 (4.66)
different single chemical shifts for carbon atoms are clearly seen.
The 19F NMR spectra of the diamagnetic porphyrazines (3a, 3b
and 3d) show a single chemical shift for the trifluoromethyl groups
at À63.46, À63.40 and À63.35 ppm, respectively.
Acknowledgement
This work was supported by the Scientific Research Fund of
Fatih University under the Project No. P50020901_1.
Electronic spectra were very useful in establishing the structure
of the porphyrazines (3a–e). The UV–Vis spectra of the porphyr-
azine core are dominated by two intense bands, the Q band be-
tween 676 and 684 nm, and the B band in the near UV region
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Fig. 5. UV–Vis spectra of 3c in chloroform at several different concentrations.