Synthesis, thermal stability and structural characterisation of iron(II) phthalocyanine complex with 4-cyanopyridine

Article abstract of DOI:10.1016/j.poly.2007.01.040

A new complex of bis-axially coordinated iron(II) phthalocyanine by 4-cyanopyridine (4-CNpy) has been obtained in crystalline form as an adduct with two 4-CNpy molecules. The [FePc(4-CNpy)₂] · 2(4-CNpy) crystallises in the monoclinic system, space group P2₁/c with two molecules in the unit cell. The iron(II) coordinates four isoindole nitrogen atoms of the almost planar phthalocyaninato(2-) macroring and axially two nitrogen atoms of 4-CNpy molecules. The coordination polyhedron around the Fe(II) atom approximates to a tetragonal by-pyramid. Four equatorial Fe-N bonds are shorter (1.936(2) A?) than two axial Fe-N bonds (2.027(2) A?). The centrosymmetric FePc(4-CNpy)₂ molecules form alternating sheets parallel to the bc crystallographic plane and solvated 4-CNpy molecules that are anti-parallel oriented by their polar cyano groups are located between the sheets of FePc(4-CNpy)₂ molecules. Ligation of the intermediate-spin iron(II) phthalocyanine by 4-CNpy molecules leads to the low spin Fe(II) complex. The importance of the d(π) → π^*(Pc) back donation is manifested in the difference between the values of C-N isoindole and C-N azamethine bond lengths of the Pc macrocycle. The thermal analysis of the crystals of [FePc(4-CN)₂] · 2(4-CNpy) shows two steps responsible for a loss of solvated (～170 °C) and coordinated (～235 °C) 4-CNpy molecules.

Full text of DOI:10.1016/j.poly.2007.01.040

Polyhedron 26 (2007) 2997–3002
www.elsevier.com/locate/poly
Synthesis, thermal stability and structural characterisation of
iron(II) phthalocyanine complex with 4-cyanopyridine
*
Jan Janczak , Ryszard Kubiak
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Oko´lna 2 str., P.O. Box 1410, 50-950 Wrocław, Poland
Received 22 November 2006; accepted 31 January 2007
Available online 7 February 2007
Abstract
A new complex of bis-axially coordinated iron(II) phthalocyanine by 4-cyanopyridine (4-CNpy) has been obtained in crystalline form
as an adduct with two 4-CNpy molecules. The [FePc(4-CNpy)2] Æ 2(4-CNpy) crystallises in the monoclinic system, space group P21/c with
two molecules in the unit cell. The iron(II) coordinates four isoindole nitrogen atoms of the almost planar phthalocyaninato(2ꢀ) mac-
roring and axially two nitrogen atoms of 4-CNpy molecules. The coordination polyhedron around the Fe(II) atom approximates to a
˚
˚
tetragonal by-pyramid. Four equatorial Fe–N bonds are shorter (1.936(2) A) than two axial Fe–N bonds (2.027(2) A). The centrosym-
metric FePc(4-CNpy)2 molecules form alternating sheets parallel to the bc crystallographic plane and solvated 4-CNpy molecules that are
anti-parallel oriented by their polar cyano groups are located between the sheets of FePc(4-CNpy)2 molecules. Ligation of the interme-
diate-spin iron(II) phthalocyanine by 4-CNpy molecules leads to the low spin Fe(II) complex. The importance of the d(p) ! p*(Pc) back
donation is manifested in the difference between the values of C–N isoindole and C–N azamethine bond lengths of the Pc macrocycle.
The thermal analysis of the crystals of [FePc(4-CN)2] Æ 2(4-CNpy) shows two steps responsible for a loss of solvated (ꢁ170 ꢀC) and coor-
dinated (ꢁ235 ꢀC) 4-CNpy molecules.
ꢁ 2007 Elsevier Ltd. All rights reserved.
Keywords: Iron phthalocyaninie; Low-spin complex; Bis-axially coordination; Crystal structure
1. Introduction
Previously, the iron and cobalt phthalocyanine crystal-
line complexes with 4-methylpyridine (4-Mepy) with the
formula of [MPc(4-Mepy)2] Æ 2(4-Mepy) (where M = Fe(II)
or Co(II)) have been studied by Cariati et al. [5]. These
compounds are also structurally isomorphic, but ortho-
rhombic. Several crystal structures of bis-axially coordi-
nated iron phthalocyanine derivatives have been reported
[6–14] but they contain iron(III) or iron(IV) in the center
of phthalocyaniniato ligand. Besides above-mentioned
bis-axially ligated iron(II) phthalocyanines, the crystal
structure of a low-spin iron(II) phthalocyanine complex
ligated by 4-methylpiperidine (4-Mepip) with the composi-
tion of [FePc(4-Mepip)2] Æ 2(4-Mepip) has been described
[15].
Iron phthalocyanine and its additive complexes are still
of wide interest because of its close analogy to the iron
porhyrin and blood hemine [1]. We are especially interested
in this study, trying to explore how the ligand bis-axially
bonded to the phthalocyanine metal influences the feature
and stability of the complex formed. A few years ago, we
have synthesised and characterised the metal(II) phthalocy-
anine complexes with bis-axially coordinated pyridine mol-
ecules: MgPc(py)2 [2], FePc(py)2 and CoPc(py)2 [3] and
MnPc(py)2 [4]. These all dipyridinated M(II)Pc complexes
are structurally isomorphic and crystallise in the mono-
clinic system.
In this paper, we describe the synthesis, thermal stabil-
ity, crystal structure and magnetic properties of bis-axially
coordinated iron(II) phthalocyanine complex by another
pyridine derivative, i.e. 4-cyanopyridine (4-CNpy).
*
Corresponding author. Tel.: +48 71 343 5021; fax: +48 71 441029.
E-mail address: j.janczak@int.pan.wroc.pl (J. Janczak).
0277-5387/$ - see front matter ꢁ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.01.040

2998
J. Janczak, R. Kubiak / Polyhedron 26 (2007) 2997–3002
2. Experimental
0.910. 5975 independent reflections (a total of 30225 reflec-
tions were integrated, Rint = 0.0579) were used for crystal
structure solution and refinement. The structure was solved
by direct methods. The hydrogen atoms of the phenyl rings
were located from the Dq maps, but in the final refinement
their positions were constrained using HFIX 43 with the iso-
tropic thermal parameters of 1.2Ueq of the carbon atoms
linked directly to the H atoms. The structure was refined with
anisotropic thermal parameters for all non-hydrogen atoms
by full-matrix least-squares methods using SHELXL-97 pro-
gram [18]. The final difference map calculation showed no
peaks of chemical significance; the largest were +0.294 and
2.1. Synthesis of the [FePc(4-CNpy)2].2(4-CNpy) complex
in the crystalline form
Iron phthalocyanine (FePc) and 4-cyanopyridine (4-
CNpy) compounds were mixed in the molar proportion
of 1:5, respectively. Next the mixture was pressed into pel-
lets of 2 g in mass. The pellet was inserted into a glass
ampoule, ca. 10 cm in length, which next was degassed
and sealed off. The sample in the ampoule was thermally
processed by about one weak. At first the temperature
was increased to 120 ꢀC. After as apparently uniform sus-
pension was formed, the temperature was increased again
to 180 ꢀC and held constant by one day and next lowered
to 150 ꢀC by a second day. As only the well developed iron
phthalocyaninato complex crystals were seen (up to 1 mm
in edge), the ampoule was firstly cooled to room tempera-
ture and next placed into temperature gradient, with 50 ꢀC
at the hot zone. After several days the excessive 4-CNpy
migrates to the cold zone. At such state the ampoule was
opened and the crystals of iron phthalocyanine complex
were selected for further experiments. Elemental analysis
of the crystalline iron phthalocyanine complex has been
performed on an energy dispersive spectrometer. Anal.
Calc. for C56H32N16Fe: Fe, 5.67; C, 68.30; N, 22.75; H,
3.28. Found: Fe, 5.72; C, 68.41; N, 22.68, H, 3.19%. We
want to add that another pellets with the various excesses
of 4-cyanopyridine were processed at lower and at higher
temperatures as well, however, these attempts were not sat-
isfactory, regarding the [FePc(4-CNpy)2].2(4-CNpy) com-
plex formation.
ꢀ0.215 e Aꢀ3. More details of the data collection parameters
˚
and the final agreement factors are collected in Table 1.
Selected bond lengths and angles are listed in Table 2.
2.4. Magnetic susceptibility measurements
The temperature dependence of the magnetic suscepti-
bility of [FePc(4-Mepy)2] Æ 2(4-Mepy) was recorded from
300 to 1.8 K on Quantum Design SQUID magnetometer
(San Diego, CA) on the sample of 85 mg. The magnetisa-
tion on magnetic field dependence was recorded from 0
to 5 T at 1.9 K.
3. Results and discussion
3.1. Characterisation of the FePc recrystallisation process in
the 4-cyanopyridine
According to our observations during several days of
thermal processing of the iron phthalocyanine with 4-
cyanopyridine (in excess), roughly three characteristic tem-
perature ranges could be distinguished. In the range above
the melting point of the 4-cyanopyridine (ꢁ80 ꢀC) and to
ca. 150 ꢀC, the suspension is formed, which again com-
pletely separates, as soon as the temperature falls below
the 4-cyanopyridine solidification point. At the tempera-
ture range 150–180 ꢀC the most characteristic products reg-
istered are the parallelepipedal violet crystals of the
additive complex of the iron phthalocyanine, [FePc(4-
CNpy)2].2(4-CNpy) and individual colourless crystals of
2,4,6-tris-(40-pyridyl)-triazine molecules that are formed
by the cyclotrimerisation of 4-cyanopyridine molecules.
The 2,4,6-tris-(40-pyridyl)-triazine crystallises in C2/c space
group of the monoclinic system and the structure was ear-
lier described [19]. When the mixture containing the violet
and colourless crystals is quickly cooled from the above-
mentioned temperature (150–180 ꢀC) to the room tempera-
ture, the crystals of iron phthalocyanine complex with 4-
cyanopyridine are preserved and can be separated for the
X-ray analysis. Otherwise, i.e. if the temperature of the
sample is slowly lowered (during a few days), the crystals
of iron phthalocyanine complex with 4-cyanopyridine van-
ish and again non-coordinated iron phthalocyanine (FePc),
in the form of fine crystalline needles, is present in the
sample.
2.2. Thermal measurements
Thermal analysis was carried out on a Lineis L81 ther-
mobalance apparatus with Pt crucibles. The powdered
Al2O3 has been used as a standard reference. The measure-
ments were performed on samples of 15–20 mg under static
air atmosphere on heating from room temperature to
300 ꢀC with the heating rate of 5 ꢀC minꢀ1
.
2.3. X-ray single crystal measurement
Data collection was carried out on a KUMA KM-4 dif-
fractometer with a two-dimensional area CCD detector.
The graphite-monochromatised Mo Ka radiation
˚
(k = 0.71073 A) and x-scan technique with Dx = 0.75ꢀ for
one image were used for data collection. The 960 images
for six different runs covering over 99% of the Ewald sphere
were performed. One image as a standard was used for mon-
itoring the stability of the intensities after every 40 images.
Integration of the intensities, corrections for Lorenz and
polarisation effects were made using a KUMA KM-4 CCD
program package [16]. The face-indexed analytical absorp-
tion was calculated using the SHELXTL program [17]; maxi-
mum and minimum transmission factors being 0.941 and

J. Janczak, R. Kubiak / Polyhedron 26 (2007) 2997–3002
2999
Table 1
ple (similar catalytic effect is observed in presence of MgPc
and has been registered by us [19]). However, progressively
with the time the thermal processing leads markedly to the
demetallation of iron phthalocyanine and destructive
decomposition (the violet phthalocyanine colour vanishes).
If the processing is interrupted at a proper moment, the
evolved nano-dispersed iron particles cause that the sample
moves under a solid magnet (the effect does not vanish even
after several months). Prolonged heating, however, causes
further, destructive transformation of the sample, leading
to the oxidation of the iron particles, and in the result
the sample does not show magnetic behaviour.
Crystal data and structure refinement for [FePc(4-CNpy)2].2(4-CNpy)
Chemical formula
Formula weight
Temperature (K)
C56H32N16Fe
984.83
295(2)
0.71073
monoclinic
P21/c
˚
Wavelength (A)
Crystal system
Space group
Unit cell dimensions
˚
a (A)
13.719(3)
15.923(3)
11.446(2)
108.86(3)
˚
b (A)
˚
c (A)
b (ꢀ)
Volume (A )
3
˚
2366.1(9)
Z
2
Dcalc and Dmeasure (Mg/m3)
Absorption coefficient (mmꢀ1
Crystal size (mm)
1.382 and 1.38
0.378
0.28 · 0.22 · 0.14
28.49
ꢀ18 6 h 6 18, ꢀ21 6 k 6 20,
ꢀ15 6 l 6 15
30225/5975/3727 (0.0579)
3.2. Thermal analysis of [FePc(4-CNpy)2].2(4-CNpy)
complex
)
hmax for data collection (ꢀ)
Limiting indices
The first marked step on TG (see Fig. 1), registered in
the range of 165–175 ꢀC, is ascribed to the loss of two lat-
tice held 4-cyanopyridine molecules from the complex, [Fe-
Pc(4-CNpy)2](4-CNpy)2 ! [FePc(4-CNpy)2] + 2(4-CNpy).
The further mass loss is observed at about 230 ꢀC. Above
this temperature two axial equivalent Fe–N(4-CNpy)
bonds break simultaneously giving FePc in a powder form.
Both processes are endothermic and characteristic of the
loss of the 4-CNpy molecules as a lattice solvent (first step)
or the loss of coordinated 4-CNpy molecules. Further
increase of the temperature leads to oxidative destruction
of the sample, since above 275 ꢀC the mass loss of the sam-
ple is observed.
Reflections collected/unique/observed
with [F2 > 2r(F2)] (Rint
)
Refinement method
full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Final Ra indices [I > 2r(I)]
wRb indices (all data)
5975/0/331
1.038
0.0595
0.1483
+0.294 and ꢀ0.215
ꢀ3
˚
Largest peak and hole on D map (e A
)
P
P
a
R = iFoj ꢀ jFci/ Fo.
P
P
2
1=2
2
b
wR ¼ f ½wðF 2o ꢀ F c2Þ ꢂ=
wF 4og ; wꢀ1 ¼ ½r2ðF 2oÞ þ ð0:0628PÞ þ
0:7299Pꢂ where P ¼ ðF 2o þ 2F c2Þ=3.
3.3. Description of the structure
Table 2
The molecular structure of [FePc(4-CNpy)2] Æ 2(4-
CNpy) complex is illustrated in Fig. 2. The central iron cat-
ion lies at the inversion center, thus the [FePc(4-CNpy)2]
molecule is centrosymmetric. The coordination polyhedron
around Fe(II) approximates to a tetragonal bypyramid.
The central iron atom and the four isoindole nitrogen
˚
Selected bond lengths (A) and angles (ꢀ) for [FePc(4-CNpy)2] Æ 2(4-CNpy)
Fe1–N2
Fe1–N4
Fe1–N21
1.938(2)
1.934(2)
2.027(2)
N2–Fe1–N4
N2i–Fe1–N4
N2–Fe1–N21
N4–Fe1–N21
90.27(9)
89.73(9)
89.64(8)
90.28(8)
C–N(pyrrole)
C1–N2
C8–N2
C9–N4
C16–N4
C–CN
C–N(azamethine)
C1–N1
C8–N3
C9–N3
C16–N1i
0
-10
-20
-30
-40
-50
1.377(3)
1.370(3)
1.371(3)
1.376(3)
1.327(3)
1.331(3)
1.330(3)
1.331(3)
C„N
C26–N22
C23–C26
1.446(4)
1.420(7)
1.137(4)
(coordinated 4-CNpy)
1.140(6)
C33–C36
C36–N32
(solvated 4-CNpy)
Symmetry code: (i) ꢀx, ꢀy, ꢀz.
50
100
150
200
250
300
At temperature 200 ꢀC and above, the processing firstly
leads to the 2,4,6-tris-(40-pyridyl)-triazine crystals growth,
which is the catalytic effect of the FePc presence in the sam-
Temperature [oC]
Fig. 1.

3000
J. Janczak, R. Kubiak / Polyhedron 26 (2007) 2997–3002
yaninato(2ꢀ) macrocycle. This conformation is the most
stable, and is preferable in the solution, due to the strongest
interaction between the ortho-H atoms of 4-CNpy mole-
cules and the N-azamethine atoms of phthalocyani-
nato(2ꢀ) macroring. This conformation is also present in
the crystal, however, due to the intermolecular interactions
and crystal packing forces this angle is slightly different
from 45ꢀ (see Table 3). This angle is comparable to that
observed in the crystal of [FePc(4-Mepy)2] Æ 2(4-Mepy) [5]
but significantly different from those in the crystal of
FePc(py)2 [3]. The differences between the rotation angle
of the axially coordinated 4-CNpy (or 4-Mepy) and pyri-
dine molecules, are likely due to the interaction with the
solvated 4-CNpy (or 4-Mepy) molecules present in the
structure.
˚
The axial Fe1–N21 bond distance is longer by ꢁ0.1 A
˚
than equatorial four Fe–N bonds [average 1.936 A]. A sim-
ilar pattern of the Fe–N bonds is observed in the other axi-
ally coordinated iron phthalocyanine derivatives (see Table
3). The values of the axial Fe–N bond lengths in axially
coordinated FePc derivatives point to their strength and
correlate well with their thermal stability. For example,
in this complex, the Fe–N(4-CNpy) bond length is shorter
than Fe–N(py) in FePc(py)2 and correlate with the thermal
breaks of the axial Fe–N bond (ꢁ235 ꢀC and ꢁ225 ꢀC for
[FePc(4-CNpy)2] Æ 2(4-CNpy) and FePc(py)2, respectively).
In the crystal of [FePc(4-Mepip)2] Æ 2(4-Mepip) complex
Fig. 2.
atoms of the phthalocyaninato(2ꢀ) macrocycle lie on a
plane. As shown in Fig. 2, the two axial 4-CNpy molecules
are coordinated by their lone-electron pair at the ring nitro-
gen atoms to the central Fe(II) atom. The dihedral angle
between the N4-isoindole plane of phthalocyaninato(2ꢀ)
macrocycle and that containing the axially coordinated 4-
CNpy molecules is close but markedly different from 90ꢀ,
i.e. 85.2(1)ꢀ. For comparison the respective value of the
deviation is not greater than 1ꢀ, when the 4-Mepy or py
molecules are ligated [3,5]. The orientation of the axial 4-
CNpy ligands relative to the phthalocyaninato(2ꢀ) mac-
roring is well described by the torsion angle of N4–Fe1–
N21–C21. The rotation of 4-CNpy ligand around the
Fe1–N21 axis would reduce the steric hindrance, i.e. the
non-bonding distances between the hydrogen atoms of
the axial 4-CNpy ligand in ortho positions and the atoms
of phthalocyaninato(2ꢀ) macrocycle. In particular, if the
rotation angle is equal 0, the 4-CNpy molecule is parallel
to the Fe1–N4 bond or at equivalent position rotated by
90ꢀ, the 4-CNpy molecule is parallel to the Fe1–N2 bond,
making the non-bonding Cꢃ ꢃ ꢃH distances greater than
˚
the elongation of the axial Fe–N bond (2.119(3) A) can
be explain by a steric effect of the 4-methylpiperidine ligand
rather than the electronic structure.
The C–C and C–N bond lengths of the phthalocyani-
nato(2ꢀ) macrocycle in the [FePc(4-CNpy)2] Æ 2(4-CNpy)
are normal in the sense that their values are not very differ-
ent from the corresponding values found in various metall-
ophthalocyanines [20]. However, it should be noted that
small differences between the values of C–N(isoindole)
and C–N(azamehtine) bond lengths are observed (see
Table 2). These differences indicate an accumulation of
the charge density on the outer carbon atoms of pyrrole
rings as well as on the bridging azamethine N atoms and
can, therefore, be explained by an important electron back
donation from the metal d(p) orbitals to the ligand p*(eg)
antibonding orbital, since the maximum charge density is
mainly located at those atoms. The accumulation of the
charge density on the outer carbon atoms of pyrrole rings
and on the bridging azamethine nitrogen atoms of phtha-
locyaninato(2ꢀ) macroring has also been evidenced in the
˚
2.6 A. The second orientation, with the rotation angle of
45ꢀ, makes the axial 4-CNpy ligand plane parallel to the
Fe1ꢃ ꢃ ꢃN(azamethine) axis and reduce the non-bonding dis-
tances between the hydrogen atoms of 4-CNpy (H in ortho
positions) and the azamethine nitrogen atoms of phthaloc-
Table 3
Comparison of the bis-axially ligated iron(II) phthalocyanine complexes and FePc
˚
˚
˚
˚
Compound
Fe–Niso (A)
Fe–Naxial (A)
Rotation angle (ꢀ)
C–Niso (A)
C–Naza (A)
Thermal stability (ꢀC)
ꢁ170–235
Reference
[FePc(4-CNpy)2] Æ 2(4-CNpy)
[FePc(4-Mepy)2] Æ 2(4-Mepy)
FePc(py)2
[FePc(4-Mepip)] Æ 2(4-Mepip)
FePc
1.936(2)
1.935(3)
1.938(2)
1.931(3)
1.926(2)
2.027(2)
2.040(3)
2.039(2)
2.119(2)
47.1(2)
42.6(4)
36.1(2)
1.374(3)
1.373(7)
1.377(3)
1.376(3)
1.378(3)
1.330(3)
1.328(4)
1.331(3)
1.324(3)
1.322(3)
this work
[5]
[3]
[15]
[24]
ꢁ225

J. Janczak, R. Kubiak / Polyhedron 26 (2007) 2997–3002
3001
4. Conclusion
The formation of the Fe–N(4-CNpy) bond, between the
central iron ion of FePc and the ring nitrogen of the 4-
CNpy, in the early stages of dissolution the iron phthalocy-
anine grains is relatively easy reversible, i.e. as long as the
bonding is not complete and not stabilised by an intermo-
lecular order of the units in the assembly. It is so, because
both FePc, as well as the ligated 4-CNpy molecules, char-
acterise a distinct planarity and strong rigidity. Moreover,
the axially coordinated 4-CNpy molecules preserve, in spite
of their marked extension in relation to that of Pc edge
value, a strong propensity for close to perpendicular orien-
tation to the Pc plane. For such extended units as building
blocks, there are only limited opportunities to arrange
themselves into a tightly packed configuration. Therefore,
the newly formed molecules composing the building block
may go again apart, and for that moment they are in the
excited state. In a consequence of it, when FePc is ther-
mally processed (recrystallised) in 4-CNpy, both compo-
nents show highly time and temperature dependent
behaviour. Here we want to add, that according to Hanack
et al. [30] one could expect also that the freshly formed
2,4,6-tris-(40-pyridyl)-triazine molecules, if it is the cause,
as -tridenadate ligand will form very stable complexes with
the FePc present in the system. However, we have not
observed the 2,4,6-tris-(40-pyridyl)-triazine splitting at
342 ꢀC or at higher temperature as mentioned in [30].
Fig. 3.
experimental density maps derived from the low tempera-
ture high resolution X-ray experiment [21–23].
The arrangement of the [FePc(4-CNpy)2] Æ 2(4-CNpy)
molecules in the unit cell is illustrated in Fig. 3. The crystal
is built up from isolated FePc(4-CNpy)2 molecules that are
related by screw axis and glide plane, which form alternat-
ing sheets parallel to the bc crystallographic plane, and sol-
vated 4-CNpy molecules (Fig. 3). The rings of solvated 4-
CNpy molecules related by an inversion center are parallel
to each other, but oriented anti-parallel by their polar
cyano groups. This orientation of solvated 4-CNpy mole-
cules reduces the repulsive forces between the dipoles of
4-CNpy molecules. The dihedral angle between the plane
of solvated 4-CNpy molecule and phthalocyaninato(2ꢀ)
macroring of 42.9(2)ꢀ and the plane of the ligated 4-CNpy
molecule of 73.8(2)ꢀ as well as the intermolecular non-
bonding distances that are greater than the sum of the com-
monly accepted van der Waals radii indicate that there are
no p–p interactions in the structure. The geometry of
ligated and solvated 4-CNpy molecules are comparable,
however, the both N–C lengths in the ring of coordinated
4-CNpy molecule are longer than in solvated one.
Appendix A. Supplementary material
Details on data collection and refinement, fractional
atomic coordinates, anisotropic displacement parameters
and full list of bond lengths and angles in CIF format have
been deposited at the Cambridge Crystallographic Data
Centre. CCDC 628342 contains the supplementary crystal-
lographic data for this paper. These data can be obtained
free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK;
fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.a-
c.uk. Supplementary data associated with this article can
be found, in the online version, at doi:10.1016/
j.poly.2007.01.040.
3.4. Magnetic properties
References
The magnetic susceptibility measurement on the sample
of [FePc(4-CNpy)2] Æ 2(4-CNpy) shows its diamagnetic char-
acter. This experiment clearly evidenced that ligation of the
[1] F.A. Walker, U. Simonis, in: L.J. Berliner, J. Reuben (Eds.),
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[2] J. Janczak, R. Kubiak, Polyhedron 21 (2002) 265.
[3] J. Janczak, R. Kubiak, Inorg. Chim. Acta 342 (2003) 64.
3
iron phthalocyanine with the intermediate state ðdxz; dyzÞ -
2
1
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