Isomorphic complexes formed by recrystallisation of M(II)Pc (M(II) = Mg, Mn and Zn) in liquid 2-amino-3-picoline

Article abstract of DOI:10.1016/j.molstruc.2009.08.007

Three isomorphic, Mg, Mn and Zn phthalocyaninato complexes monoaxially ligated by 2-amino-3-picoline (2A3P) are obtained. They crystallise with 2A3P molecule as solvent molecule in the centrosymmetric space group P2₁/c of monoclinic system. The

Full text of DOI:10.1016/j.molstruc.2009.08.007

Journal of Molecular Structure 937 (2009) 25–33
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Isomorphic complexes formed by recrystallisation of M(II)Pc (M(II) = Mg, Mn
and Zn) in liquid 2-amino-3-picoline
*
Jan Janczak , Ryszard Kubiak, Ewa Bukowska
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-950 Wrocław, Okólna 2 str., P.O. Box 1410, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 July 2009
Received in revised form 5 August 2009
Accepted 6 August 2009
Available online 11 August 2009
Three isomorphic, Mg, Mn and Zn phthalocyaninato complexes monoaxially ligated by 2-amino-3-pico-
line (2A3P) are obtained. They crystallise with 2A3P molecule as solvent molecule in the centrosymmet-
ric space group P2
coordinated by four isoindole N atoms of Pc macrocycle in equatorial position, and by ring N atom of
A3P molecule in an axial position. The M(II) due to the interaction with an axial 2A3P molecule is sig-
1
/c of monoclinic system. The central M(II) atom in these complexes, M(II)Pc(2A3P), is
2
nificantly displaced from the plane defined by four isoindole N atoms of Pc macrocycle toward the ring N
atom of 2A3P molecule. The stability of these complexes in solid was analysed by thermogravimetric
measurements. The Mg and Zn complexes in solution are stable under air condition, while the Mn
Keywords:
Metallophthalocyanines
Magnesium
Manganese
Zinc
complex is moderately stable in solution and after several days transforms into
phthalocyanine complex. The magnetic susceptibility of the MnPc(2A3P) ꢀ 2A3P complex shows the
Curie–Weiss behaviour in the temperature range of 300–75 K. The calculated eff indicates on high-spin
l-oxo manganese(III)
Crystal structure
Thermal stability
l
complex. Below 75 K, the leff drastically lowered to the value of ꢁ3.62 lB indicating the intermediate-
spin complex. In addition, the co-crystals of 2:1 composition of 2A3P:1,2-dicyanobenzene were isolated
during the preparation of the MgPc(2A3P) ꢀ 2A3P.
Ó 2009 Elsevier B.V. All rights reserved.
1
. Introduction
The metallophthalocyanines, MPc’s, are still very intensively
the centre of essentially planar, rigid and extended Pc, than is clear
that in such cause, when the 2A3P molecule is additively bonded
by its N ring atom, than it is not more capable to attract effectively
the M atom of any second MPc by the amine group. If so, the mate-
rial recrystallised may consist the metallophthalocyanine units
only in the forms as illustrate Scheme 1.
Furthermore, both groups attached to the ring of 2A3P molecule
should not be regarded as only sterical hindrances influencing the
arrangement mode in the crystalline network formed, but also as
functional moieties offering the possibility of the various weak
interactions contributing to the stabilisation of the specific struc-
ture. Therefore to characterize the specific interactions between
the molecules in the solid-state, the crystals of the title M(II)Pc-
2A3P system have been obtained. The X-ray results described here
will be helpful for better understanding of the interactions be-
tween the molecules developing the 3D architecture.
studied multiply functional compounds, useful for industry and
modern technology as colorants and sensors [1–4]. The simple
method to tune their properties is the recrystallisation of MPc’s
in various solvents. Obviously the recrystallisation effect, i.e. what
material is produced in such a way, depends on the MPc – solvent
balance conditions realised in the individual system. Among the
solvents used, the pyridine and its derivatives are well known as
effective media for recrystallisation and as ligating N-donors. As
concerns the MgPc, MnPc and ZnPc compounds, they all show sim-
ilar columnar stacks of the molecules in the solid from [5–7]. How-
ever, in the case of the structures of their additive complexes with
N-donating bases, only the biaxial (4 + 2) complexes of MgPc and
of MnPc, and monoaxial (4 + 1) in case of ZnPc are known from
the X-ray diffraction studies [8–10]. By analogy with these exper-
imental results, one could expect that with 2-amino-3-picoline
2
. Experimental
(
2A3P) the respective M(II)Pc complexes, showing the similar cen-
tral M coordination geometries, corresponding to coordination
number 4 + 2 for Mg(II) and Mn(II), but 4 + 1 for Zn(II) would be
formed. Besides, if we recognize that in the MPc the M residue in
2
.1. Preparation
The MgPc used in the synthesis procedure was prepared as de-
scribed elsewhere [5]. The ZnPc and MnPc were obtained from
Aldrich. Although, the bottles were labelled as zinc and manganese
phthalocyanines the analysis implies on the small amount of
*
Corresponding author.
E-mail address: j.janczak@int.pan.wroc.pl (J. Janczak).
0
022-2860/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2009.08.007

2
6
J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
L
L
M
L
+
L
M
M
and/or
CH3
where
M
=
M(II)Pc,
L =
NH2
N
Scheme 1.
impurity. Both phthalocyanines were purified by heating under
vacuum at about 210 °C. After one day the purity of both metall-
ophthalocyanines have been checked on energy dispersive spec-
trometer. Th X-ray powder diffraction patterns clearly shown
that the metallophthalocyanines after heating procedure exist in
the b-modification. The single crystals of MgPc(2A3P) ꢀ 2A3P,
ZnPc(2A3P) ꢀ 2A3P and MnPc(2A3P) ꢀ 2A3P were obtained by
the following procedure. A suspension of 0.5 g metallophthalocya-
nine (MgPc, ZnPc or MnPc) in 5 ml 2-amino-3-picoline was heated
in an evacuated glass ampoule (c.a. 10 cm) at the temperature
gradient. Hot zone 140 °C and cold zone 80 °C. After one day during
the heating procedure violet crystals of the respective metal(II)-
phthalocyaninato complexes (MgPc(2A3P) ꢀ 2A3P, ZnPc(2A3P) ꢀ
strained: thermal parameters and distances. Details of the data col-
lection parameters, crystallographic data and final agreement
parameters are collected in Table 1. Selected geometrical parame-
ters are listed in Table 2.
2.4. Thermal measurements
Thermal analysis was carried out on a Lines L81 thermobalance
apparatus with Pt crucibles. Powdered Al O has been used as a
2
3
reference. The measurements have been performed under static
air atmosphere on heating from room temperature to 300 °C at
ꢃ1
the heating rate of 5 °Cꢂmin
.5. UV–vis measurements
The electronic absorption spectra measurements were carried
.
2
A3P and MnPc(2A3P) ꢀ 2A3P) in various size were formed. Ele-
2
mental analyses were carried out on an energy dispersive spec-
trometer. Found for MgPc(2A3P) ꢀ 2A3P: C, 70.32; N, 22.35; H,
4
4
4
2
.22; Mg, 3.11%, for ZnPc(2A3P) ꢀ 2A3P: C, 66.68; N, 21.10; H,
.12; Zn, 8.10%, for MnPc(2A3P) ꢀ 2A3P: C, 67.64; N, 21.41; H,
.03; Mn, 6.92%. Calculated for Mg(2A3P) ꢀ 2A3P: C, 70.17; N,
2.32; H, 4.28 and Mg, 3.23%, for ZnPc(2A3P) ꢀ 2A3P: C, 66.54;
out at room temperature using a CARY-VARIAN SE UV–vis–NIR
spectrometer. The spectra of the samples were recorded in pyri-
dine solutions.
N, 21.16; H, 4.06; Zn, 8.24%, for MnPc(2A3P) ꢀ 2A3P: C, 67.43; N,
2.6. Magnetic susceptibility measurements
2
1.45; H, 4.12; Mn, 7.00%.
The temperature dependence of the magnetic susceptibility of
2
.2. X-ray powder diffraction measurements
MnPc(2A3P) ꢀ 2A3P was recorded from 300 to 1.8 K on Quantum
Design SQUID magnetometer (San Diego, CA) on the sample of
115 mg. The magnetization on magnetic field dependence was re-
corded from 0 to 5 T at 1.9 K.
The purified started metallophthalocyanines as well as the rest
of the samples left after thermogravimetric analyses were mea-
sured on a STOE powder diffratometer equipped with a linear po-
sition detector (PSD) [11] using Cu K
at room temperature.
1
a radiation (k = 1.540562 Å)
3
. Results and discussion
3.1. Synthesis and characterization
2.3. Single crystal X-ray crystallography
The M(II)Pc(2A3P) ꢀ 2A3P crystals (M = Mg, Mn and Zn) were
Suitable single crystals of MgPc(2A3P) ꢀ 2A3P, MnPc(2A3P) ꢀ
A3P, ZnPc(2A3P) ꢀ 2A3P and bis(2-amino-3-picoline) ꢀ 1,2-dicy-
obtained by recrystallization of the respective b = M(II)Pc’s in 2-
amino-3-picoline (2A3P). A suspension of M(II)Pc in 2A3P was
heated in an evacuated glass ampoule at the temperature gradient
during one day. During the heating process the M(II)Pc molecule
interacts by its positively polarized central metal with the lone
electron pair of the N ring atom of 2A3P. As a result of the interac-
tions the axial M–N bond is formed yielding the monoaxially
ligated M(II)Pc(2A3P) complex. During the migration of the formed
M(II)Pc(2A3P) molecules to the cold temperature zone (ꢁ80 °C)
2
anobenzene were used for data collection on a four-circle KUMA
KM4 diffractometer equipped with two-dimensional CCD area
detector [12]. The graphite monochromatized Mo-K
a radiation
(
k = 0.71073 Å) and the -scan technique ( = 1°) were used
x
Dx
for data collection. Data collection and reduction along with
absorption correction were performed using CrysAlis software
package [12]. The structures were solved by direct methods using
SHELXS-97 giving positions of almost all non-hydrogen atoms. The
remaining atoms were located from subsequent difference Fourier
syntheses. The structures were refined using SHELXL-97 [13] with
the anisotropic thermal displacement parameters. Hydrogen atoms
of the phthalocyanine moieties, 2A3P and 1,2-dicyanobenzene
molecules were located from the difference Fourier maps, but in
the final refinement the positions of all hydrogen atoms were con-
they interact with each other via
p–p clouds of Pc macrorings as
well as with the solvent 2A3P molecules. This initiates the crystal-
lisation process and with the time the well developed violet crys-
tals of M(II)Pc(2A3P) ꢀ 2A3P appear. The crystals were separated
from the excess of the 2A3P by filtration. In the filtrate, from which
were separated the MgPc(2A3P) ꢀ 2A3P crystals, after several days
few colourless crystals appear. The elemental analysis and single

J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
27
Table 1
Crystallographic data for M(II)Pc(2A3P) ꢀ 2A3P (M(II) = Mg, Mn and Zn) and for the 2:1 co-crystal of 2A3P and 1,2-DCB.
Formula
MgC44H
32
N
12
MnC44
H
32
N
12
ZnC44
H
32
N
12
18 20 4
C H N
Molecular weight
Temperature
Crystal system
753.13
295(2)
783.76
295(2)
794.19
295(2)
344.42
295(2)
Monoclinic
P2 /c (No. 14)
Monoclinic
P2 /c (No. 14)
Monoclinic
P2 /c (No. 14)
Monoclinic
P2 /n (No. 14)
Space group
1
1
1
1
0
16.765(2)
24.619(3)
9.139(2)
16.692(2)
24.581(3)
9.125(1)
16.840(2)
24.593(3)
9.115(2)
7.924(1)
15.014(3)
16.301(3)
a ( AÅ )
0
b ( AÅ )
0
c ( AÅ )
b (°0)
V ( ÅA )
101.34(2)
3698.4(10)
100.94(2)
3676.0(8)
101.98(2)
3692.7(10)
93.68(2)
1935.3(6)
3
Z
4
4
4
4
D
D
l
calc
1.353
1.35
0.10
0.48 ꢀ 0.14 ꢀ 0.11
43422/9289
0.048
0.045
0.079
1.416
1.41
0.41
0.46 ꢀ 0.16 ꢀ 0.14
33106/7769
0.041
0.072
0.177
1.429
1.42
0.72
0.42 ꢀ 0.14 ꢀ 0.12
42784/9264
0.047
0.050
0.124
1.182
1.18
0.07
0.32 ꢀ 0.25 ꢀ 0.15
23442/4821
0.044
0.048
0.122
obs.
ꢃ1
(mm
)
3
Crystal size (mm )
Total/unique refls
(R )
int
2
2
(F )]a
R [F > 2
r
wR [F2 all refls]
b
S
1.001
+0.31; ꢃ0.21
1.002
+1.27; ꢃ1.19
1.001
+0.71; ꢃ0.50
1.01
+0.12; ꢃ0.13
0
ꢃ3
D
q
max
,
D
q
min (eꢂÅA
)
a
R =
wR = {
R
||F
R
o
| ꢃ |F ||/
c o
RF .
b
2
2 2
4}½; w–1
2(F
2) + (aP)2 + bP where P = (F 2
+ 2F 2
[w(F
o
ꢃ F
c
) ]/
R
wF
o
=
r
o
o
c
)/3. The a and b parameters are: 0.0192 and 0 for Mg, 0.058 and 9.57 for Mn, 0.0598 and
0
.306 for Zn compounds and 0.034 and 0 for the 2:1 co-crystal of 2(2A3P):(1,2-DCB).
Table 2
solution, the M(II)Pc(2A3P) complexes are moderately stable due
to the exchange of the axial ligand. In the case of Mg and Mn com-
plexes in dry pyridine the exchange of 2A3P to pyridine leads to
Selected geometrical parameters (Å, o).
MgPc(2A3P) ꢀ 2A3P MnPc(2A3P) ꢀ 2A3P ZnPc(2A3P) ꢀ 2A3P
the formation of biaxially coordinated MgPc(py)
2
[8] and
M–N2
M–N4
M–N6
M–N8
M–N9
N2–M–N4 87.39(5)
N2–M–N6 151.96(6)
N2–M–N8 85.81(6)
N4–M–N6 86.30(5)
N4–M–N8 152.43(6)
N6–M–N8 87.36(5)
N2–M–N9 102.97(6)
N4–M–N9 105.71(6)
N6–M–N9 105.04(6)
N8–M–N9 101.85(6)
2.0353(14)
2.0419(14)
2.0368(13)
2.0365(14)
2.1768(17)
2.051(3)
2.069(3)
2.053(3)
2.080(3)
2.035(2)
2.037(2)
2.032(2)
2.036(2)
2.157(2)
87.69(8)
153.19(8)
85.66(8)
86.71(7)
153.37(8)
87.69(8)
101.55(8)
105.78(8)
105.20(8)
100.82(8)
MnPc(py) [9], while in the case of Zn to the monoaxially coordi-
2
nated ZnPc(py) complex [10,15]. The equilibrium between the
form of the complexes in pyridine solution strongly depends on
the environment conditions, like moist atmosphere, or on the ex-
pose to air. In the case of wet-pyridine the MgPc(2A3P) complex
transforms into the aqua(phthalocyaninato)magnesium complex
due to the affinity of the central Mg to water molecule [16,17].
The exposure of MnPc(2A3P) in pyridine solution on the air condi-
2.248(4)
86.55(10)
148.65(12)
84.82(10)
86.34(10)
149.56(12)
84.04(10)
104.52(11)
105.08(11)
106.82(11)
105.34(11)
tion transforms the Mn complex into the l-oxo-bis[phthalocyani-
nato(2-)]manganese(III) complex as a result of the oxidation [18].
These processes have been described in details in the previous pa-
per [9]. In the case of ZnPc(2A3P) in pyridine solution are no ob-
served any change during expose on air or moist atmosphere.
crystal X-ray experiment indicate on the 2(2-amino-3-pico-
line):(1,2-dicyanobenzene) composition of the colourless crystals.
Since the started MgPc was obtained from pure powder Mg and
3.2. Thermal stability
In order to determine the thermal stability of the complexes
investigated here, the thermogravimetric analysis of the Mg, Mn
and Zn complexes were carried out on the samples of 50 mg and
1
,2-dicyanobenzene as described elsewhere [5], after the prepara-
tion procedure of MgPc the small amount of 1,2-dicyanobenzene as
impurity was present in the started sample, which is well soluble
in the 2A3P. For this reason in the result of MgPc(2A3P) ꢀ 2A3P
preparation process, in the filtrate after several days the 1,2-dicy-
anobenzene recrystallised, yielding 2(2A3P)(1,2-DCB) co-crystals.
The obtained MgPc(2A3P) ꢀ 2A3P, MnPc(2A3P) ꢀ 2A3P and
ZnPc(2A3P) ꢀ 2A3P crystals are well soluble in an aromatic sol-
vents like pyridine, 2-, 3- and 4-picoline, dioxan and other aro-
matic solvents containing N or O donor atoms. The solubility in
the other aromatic solvents like benzene or 1-chloronaphthalene
is significantly lower than that in N- and O-heteroaromatic sol-
vents. The solubility in water is not significant. The contact of the
complexes with non-oxidising dilute acids lead to the demetalla-
ꢃ1
with the heating rate of 5 °C min . The thermogravimetric analy-
ses of the complexes are shown in Fig. 1. The thermal analyses of
the Mg, Mn and Zn complexes show that these compounds under-
go very similar decomposition processes, consisting of the
stepwise cleavage of the 2A3P molecules from the starting com-
pounds. Generally, at lower temperature the samples loss the sol-
vated molecules and at higher temperature loss the coordinated
2A3P. The respective mass loss registered for the complexes are:
ꢁ14.0 and 28.5% for MgPc(2A3P) ꢀ 2A3P, ꢁ14 and 28% for
MnPc(2A3P) ꢀ 2A3P and ꢁ13.5 and 27.5% for ZnPc(2A3P) ꢀ 2A3P,
and agrees well with the expected values responsible for the loss
of solvated and coordinated 2A3P molecules from the samples
(see Table 3). The solvated 2A3P molecule is released from the
samples at slightly different temperature, at ꢁ165 °C in the Mn,
at ꢁ170 °C in Zn and at ꢁ180 °C in Mg. This can be understand if
we take into account the interactions of the solvated 2A3P
tion yielding metal-free phthalocyanine in the a-form [14], which
was identified by the X-ray powder diffraction method [11]. The
obtained MgPc(2A3P) ꢀ 2A3P, MnPc(2A3P) ꢀ 2A3P and ZnPc-
(
2A3P) ꢀ 2A3P crystals are stable under air atmosphere, but in

2
8
J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
0
complexes is closely related with the electronic structure of the
0
5
central M(II) and with the strength of the axial M–N bond (see Ta-
ble 2). The shortest axial M–N bond is observed in the most stable
Zn-complex, while the longest M–N bond is found in the Mn-com-
plex with the lowest thermal decomposition within the complexes
studied here. The decomposition processes, i.e. loss of solvated and
loss of coordinated 2A3P molecules, are endothermic processes as
illustrate the DTA curves (Fig. 1).
.
MgPc(2A3P)2A3P
-
-
1
-
-
-
-
-
10
15
20
25
30
-2
3.3. Description of the structures and molecular arrangement
MgPc
The investigated crystals of M(II)Pc(2A3P) ꢀ 2A3P complexes
-3
are isomorphic. The asymmetric unit consists of one monoaxially
ligated by 2-amino-3-picoline M(II)Pc molecule and one 2A3P sol-
vated molecule (Fig. 2). The geometries of these three molecules
are quite similar (Table 4). The M(II)Pc unit in these complexes is
not planar, and the central M(II) atom exhibits 4 + 1 geometry,
coordinated equatorially by four isoindole N atoms of Pc macrocy-
cle and by the ring N atom of an axial 2A3P molecule. The coordi-
nation of the Mg and Mn central atom of M(II)Pc by ring N atom of
50
100
150
200
250
300
Temperature [ºC]
0
0
.
ZnPc(2A3P) 2A3P
-
5
-
1
2
3
-
-
-
-
-
10
15
20
25
30
aromatic ligands is different to that found in MgPc(py)
2
[9],
MgPc(4-Mepy) [10], and MnPc(py) (all 4 + 2 coordinated com-
2
2
plexes) due to the steric hindrance of the amine group in the ortho
position in relation to the ring N atom. The planar M(II)Pc
molecules, upon ligation by 2A3P, adopt the saucer shape form,
due to the interaction of the oppositely charged central M(II) atom
of M(II)Pc with the ring N atom (containing lone electron pair) of
the axial 2A3P molecule. This interaction leads to deviation of
the M(II) from the centre cavity of the Pc macrocycle toward the
coordinated 2A3P molecule, making the four equatorial M(II)–N
bonds longer by ꢁ0.1 Å in relation to the parent M(II)Pc complexes
-
-
ZnPc
50
100
150
200
250
300
Temperature [ºC]
[
5–7]. Interaction between the ring N atom, with a lone-pair of
0
electrons, and the positively polarized M(II) atom of M(II)Pc mole-
cules leads to deviation of the central M(II) by 0.489(2), 0.549(2)
and 0.470(2) Å from the plane defined by the four isoindole N
atoms of Pc macrocycle in the Mg, Mn and Zn-complexes, respec-
tively. The orientation of the 2A3P molecule ligated the central
M(II) atom in relation to the Pc macrocycle is well described by
the torsion angle of N2–M(II)–N9–C37 (M(II) = Mg, Mn and Zn).
The rotation of the 2A3P molecule around the axial M(II)–N(9) axis
would reduce the steric hindrance effect, i.e. the non-bonding dis-
tances between the hydrogen atom of amine group and the hydro-
gen atom in ortho position in relation to the ring N atom and the
atoms of Pc macrocycle. In particular, if the rotation angle is equal
0, the 2A3P molecule is parallel to the M(II)–N2 bond, or at the
0
-
5
.
MnPc(2A3P)2A3P
-
-
-
-
-
10
15
20
25
30
-
1
2
3
-
MnPc
-
50
100
150
200
250
300
o
Temperature [ºC]
equivalent position rotated by 90 , the 2A3P molecule is parallel
to M(II)–N4 bond. The second orientation, with the rotation angle
Fig. 1. Thermogram for the MgPc(2A3P) ꢀ 2A3P (a), MnPc(2A3P) ꢀ 2A3P (b) and
o
ꢃ1
of 45 , makes the axial 2A3P ligand plane parallel to the
ZnPc(2A3P) ꢀ 2A3P (c) complexes. Speed rates 5°Cmin
.
ꢂꢂꢂ
M(II) N(azamethine) axis. This orientation is realised in all
investigated here complexes and is the most stable conformation
ꢂꢂꢂ
ꢂꢂꢂ
which is stabilised by the C37–H37 N1 and N10–H10B N5 inter-
actions between the H atoms of 2A3P molecule and the Pc macro-
cycle (Table 5).
molecules with the M(II)Pc(2A3P) leading to the formation of the
D-architecture of the crystals (details of the molecular interac-
3
tions are described in the next paragraph). After loss of the sol-
vated 2A3P molecules, the thermal stability of the M(II)Pc(2A3P)
The main differences between the Mg, Mn and Zn –structures
are found in the axial M(II)–N bond distances (see Table 2). The
Table 3
Comparison of the TG, DTA and XRD data for the solid-state samples of M(II)Pc(2A3P) ꢀ 2A3P complexes.
Compound
TG (weigth loss,%)
calc. weight loss, (%)
DTA
XRD identified residue
MgPc(2A3P) ꢀ 2A3P
ꢁ180°C, 14.0 (solvated 2A3P)
14.36
28.72
13.80
27.60
13.62
27.23
Endothermall
Endotherma
Endothermal
Endotherma
Endothermal
Endothermal
b-MgPc
ꢁ
240°C, 28.5 (coordinated 2A3P)
MnPc(2A3P) ꢀ 2A3P
ZnPc(2A3P) ꢀ 2A3P
ꢁ165°C, 14.0 (solvated 2A3P)
220°C, 27.0 (coordinated 2A3P)
ꢁ170°C, 14.1 (solvated 2A3P)
270°C, 27.0 (coordinated 2A3P)
b-MnPc
b-ZnPc
ꢁ
ꢁ

J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
29
ferences in these three structures can be found in the dihedral an-
gle between the N -isoindole plane of Pc macrocycle and the ring
plane of coordinated 2A3P molecule (Table 4). The solvated 2A3P
molecule is almost perpendicular to the plan of Pc macrocycle
and is almost parallel to the plane of coordinated 2A3P molecule
C42
C41
C43
N11
4
C40
C39
C38
C35
(Table 4). Although, the solvated 2A3P molecule is not directly
N12
C36
C34
N10
joined to the M(II)Pc molecule, its orientation is determined by
the weak interactions between the hydrogen atoms of 2A3P sol-
vated molecule and the azamethine nitrogen atoms of Pc macrocy-
C44
C33
N9
C37
C11
C10
C12
C5
C6
C13
C14
i
ꢂꢂꢂ
i
cle, C43–H43ꢂꢂꢂN1 and N10–H10B N5 , i = ꢃx, 1 ꢃ y, ꢃz (see Table
N3
C7
C1
C9
C8
6
). Both interactions are relatively weak, but important and deter-
C4
C15
N5
C17
mine the orientation of the solvated 2A3P molecule in relation to
M(II)Pc(2A3P) complex. In addition, the ring N atom with lone
electron pair of the solvated 2A3P molecule acts as acceptor in
the hydrogen bond (Table 7).
C2
N1
N4
C16
C3
N2
Mg
N6
C18
C32
C19
N8
C26
C25
C31
C20
C21
C24
The mutual arrangement of M(II)Pc(2A3P) ꢀ 2A3P molecules
C30
C29
N7
C23
and the crystal packing is mainly determined by the p–p interac-
C28
C42
C27
C22
tions (Fig. 3). The M(II)Pc(2A3P) molecules related by an inversion
interact via in the back-to-back fashion with the interplanar
distance between the N -planes of Pc rings compared to the sum
of van der Waals radii of the
-aromatic ring system (ꢁ3.4 Å, see
p–p
C43
C39
4
p
C41
Table 7) [19]. The overlap of the Pc macrocyclic ligands in this
manner is characteristic of five coordinate (4 + 1) M(II)-phthaloc-
yaninate(2-) complexes (Fig. 3). Scheidt and Lee [20] examined
the overlap in neutral, structurally characterized, sterically unhin-
dered metal-porphyrinato complexes and discovered that the dis-
N11
C40
C35
C38
C34
N12
C44
C5
N10
C36
C37
C33
tribution of the overlap of the ligands is trimodal rather than
N9
ꢂꢂꢂ
continuous. The N
4
N
4
distances between the back-to-back ori-
C11
C10
C12
C6
C13
ented Pc macrocycles observed in these structures (Table 7) repre-
sent an intermediate overlap between the -aromatic ring system.
N3
C4
C7 C8
C9
p
C14
N5
However, owing to the saucer shape of the Pc ligands, the mean
C15
N2
C3 C2 C1
N1
N4 C16
interplanar separations between the 40-atoms rings of back-to-
Mn
ꢂꢂꢂ
C32
C17
back oriented dimers are shorter by ꢁ0.32 Å than the N
4
N
4
values
N8
N6
C18
C31
given in Table 7, and are nearly midway between the sum of the C
atom van der Waals radii of the
-aromatic rings (ꢁ3.4 Å) and the
distance at which the steric interactions between the -aromatic
C30
C19
C20
p
C24
C25
C26
N7
C23
p
C21
ring system becomes predominantly repulsive (ꢁ3.08 Å).
C29
C22
C28
C27
C39
The asymmetric unit of the 2(2-amino-3-picoline): (1,2-dicya-
nobenzene) co-crystals obtained as by-product during the
MgPc(2A3P) ꢀ 2A3P consists of two 2A3P molecules and one mol-
ecule of 1,2-dicyanobenzene (1,2-DCB) (Fig. 4). The 2A3P mole-
C42
C41
C43
N11
ꢂꢂꢂ
cules interact via N–H N hydrogen bonds (Table 8) forming
dimeric units. The bond distances and angles of 2A3P molecules
are similar and compared with those found in the ligated and sol-
vated 2A3P molecules in the M(II)Pc(2A3P) ꢀ 2A3P complexes
C40
C38
C35
C34
N12
(
within the 3 e.s.d’s), while the bond distances and angles of 1,2-
C44
C33
N9
N10
C11
DCB molecule are quite similar to that found in the crystal of pure
1,2-DCB [21]. Molecular architecture and the crystal packing is
mainly determined by the - cloud interactions between the aro-
matic rings of 2A3P and 1,2-DCB molecules (Fig. 5).
C36
C37
C5
C6
C12
C13
N3
C4
C7
C8
C9
C10
C1
C15 C14
N5
C2
N4 C16
C3
N2
C32
3.4. UV–vis spectroscopy
Zn
N1
C17
N6
C18
C31
C28
N8
C26
C27
C30
C19
C20
The electronic absorption spectra of fresh solution of the inves-
tigated complexes in pyridine are shown in Fig. 6. The spectra of
the Mg and Zn complexes are very similar and show a typical Q
and B bands characteristic for the phthalocyaninate(2-) ligand.
The Q band corresponds to excitation between the HOMO to LUMO
level. As can be seen from the Fig. 6a and c the Q band exhibits
C24
C25
C23
N7
C29
C22
C21
Fig. 2. Molecular structure of the MgPc(2A3P) ꢀ 2A3P (a), MnPc(2A3P) ꢀ 2A3P (b)
and ZnPc(2A3P) ꢀ 2A3P (c) complexes with labelling scheme Displacement ellip-
soids are shown at the 50% probability level. H atoms are shown as spheres with
arbitrary radii.
1
splitting, which has been mentioned in the literature as Q and
Q
2
bands [22,23]. The splitting value of ꢁ60 nm is likely due to
the vibronic coupling in the excited state as was suggested in the
literature [24]. The bands observed in the UV–vis spectrum of Mg
and Zn complexes well correlate with that observed for the MgPc
and ZnPc complexes of the vapour phase [25]. Additionally, in
the spectral region of 600–700 nm, besides the two distinctly
values of the axial M(II)–N coordination bond lengths in these
complexes indicate on their strength and well correlate with the
thermal stability as shown the TG analyses. In addition, small dif-

3
0
J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
Table 4
Comparison of the geometries of the M(II)Pc(2A3P) ꢀ 2A3P complexes.
MgPc(2A3P) ꢀ 2A3P
MnPc(2A3P) ꢀ 2A3P
ZnPc(2A3P) ꢀ 2A3P
Average of the four equatorial M–N bonds, (Å)
Axial M–N bond, (Å)
2.037
2.063
2.035
2.1768(17)
0.489(2)
50.7(1)
99.7(2)
7.7(2)
2.248(4)
0.549(2)
51.4(2)
103.6(2)
6.1(3)
2.157(2)
0.470(2)
50.6(1)
98.3(2)
7.5(2)
Displacement of the M(II) from the N
Orientation of the ligated 2A3P molecule in relation to the Pc,N2–M(II)–N9–C37, (°)
Inclination of the ring-plane of ligated 2A3P in relation to the N -plane of Pc, (°)
Dihedral angle between the planes of solvated and coordinated 2A3P molecules, (°)
Inclination of the solvated 2A3P molecule to the N -plane of Pc, (°)
4
-isoindole plane of Pc, (Å)
4
4
100.4(2)
105.6(2)
99.6(2)
Table 5
Comparison of the C–HꢂꢂꢂN and N–HꢂꢂꢂN intramolecular contacts that stabilise the geometry of M(II)Pc(2A3P) ꢀ 2A3P molecules.
D–HꢂꢂꢂA
MgPc(2A3P) ꢀ 2A3P
MnPc(2A3P) ꢀ 2A3P
ZnPc(2A3P) ꢀ 2A3P
D–H, HꢂꢂꢂA, DꢂꢂꢂA, <DHA
D–H, HꢂꢂꢂA, DꢂꢂꢂA, <DHA
D–H, HꢂꢂꢂA, DꢂꢂꢂA, <DHA
C37–H37ꢂꢂꢂN1
0.93, 2.821, 3.794(3), 157
0.86, 2.616, 3.419(3), 156
0.93, 3.125, 3.972(3), 153
0.86, 2.647, 3.430(3), 152
0.93, 2.836, 3.717(2), 158
0.86, 2.593, 3.396(3), 156
N10–H10AꢂꢂꢂN5
Table 6
The shortest C–HꢂꢂꢂN contacts stabilised the orientation of the solvated 2A3P molecule in the M(II)Pc(2A3P) ꢀ 2A3P crystals.
Compound
D–HꢂꢂꢂA, (Å, °)
i
I
i
C43–H43
H43ꢂꢂꢂN5
C43ꢂꢂꢂN5
C43–H43ꢂꢂꢂN5
MgPc(2A3P) ꢀ 2A3P
MnPc(2A3P) ꢀ 2A3P
ZnPc(2A3P) ꢀ 2A3P
0.93
0.93
0.93
2.528
2.589
2.502
3.456(3)
3.502(3)
3.472(3)
175
167
173
Symmetry code: i = ꢃx, 1 ꢃ y, ꢃz.
Table 7
Comparison of the hydrogen bonds geometry and the back-to-back N
4
ꢂꢂꢂN distance in the crystals of M(II)Pc(2A3P) ꢀ 2A3P complexes.
4
Compound
D–HꢂꢂꢂA
D–H (Å)
HꢂꢂꢂA (Å)
2.42
2.31
2.44
DꢂꢂꢂA (Å)
3.165(3)
3.080(3)
3.187(3)
<(DHA), (°)
N
4
ꢂꢂꢂN
4
, (Å)
i
i
i
Mg
Mn
Zn
N10–H10BꢂꢂꢂN1
N10–H10BꢂꢂꢂN1
N10–H10BꢂꢂꢂN1
0.86
0.85
0.86
145
150
146
3.525(3)
3.532(3)
3.581(3)
Symmetry code: i = ꢃx, 1 ꢃ y, ꢃz.
ꢃ6
3
ꢃ1
separated Q
1
and Q
2
bands, a shoulder is observed. This shoulder is
nate)2-) macrocycle (ꢃ290 ꢀ 10 cm mol ) and the 2A3P mole-
ꢃ6
3
ꢃ1
also observed in the vapour-phase spectrum of MgPc and ZnPc as
well as in solution [25,26].
cules (ꢃ48 ꢀ 10 cm mol ) have been included for the molar
susceptibility [29]. The experimental data in the temperature re-
gion of 300–75 K are well approximated by a Curie–Weiss law with
The electronic absorption spectrum of fresh solution of the
MnPc(2A3P) ꢀ 2A3P complex in pyridine is shown in Fig. 6b (solid
line). The Q band in solution splits into two bands at ꢁ666 and
the value of
netic moment calculated for the MnPc(2A3P) ꢀ 2A3P at room tem-
perature (298 K) is eff = 5.82 and is slightly lower than the value
of 5.92 calculated for the spin-only magnetic moment for S =
5/2. The slightly lower value of eff than the calculated is likely
H
ffiꢃ5.5 K for the Curie constant. The effective mag-
ꢁ
690 nm. After exposure of the solution of the Mn-complex to
l
l
B
air during one weak, the spectrum was registered again (see
Fig. 6b, dashed line). On introduction of air the Q bands character-
istic for the Mn(II) phthalocyaninato complex decreased, and the
new bands (ꢁ568, ꢁ611 and ꢁ718 nm) are appeared. These bands
have been assigned to the transitions in the dinuclear manga-
l
B
l
due to the fact that the starting MnPc(2A3P) ꢀ 2A3P solid state
sample used for the magnetic measurement was not entirely pure,
since it is moderately stable in air, and some amount of the l-oxo-
3
+
nese(III)
l-oxo-complex [18], which is formed by oxidation of
manganese(III) complex was present. The cation Mn with four
electrons exhibits diamagnetic character due to spin pairing which
is unusual for this ion but possible under two conditions: (1) anti-
ferromagnetic interactions between oxygen bridged Mn(III) ions
the starting M(II)Pc(2A3P) complex in pyridine solution by O
2
. This
assignment is in agreement with the suggestions of Yamamoto
et al. [27] that studied the oxidation and reduction reactions of
MnPc in solution of several solvents [28]. The spectra of the Mg
and Zn complexes taken after exposure of the solution on air by
one weak do not shown any changes related to the exchange of
an axial 2A3P ligand to pyridine.
g
and/or (2) by pairing of the electrons on the dxz,dyz orbitals (e ) that
are the lowest lying of the manganese(III) d-orbitals as has been
suggested by Yamamoto et al. [30]. Thus the MnPc(2A3P) ꢀ 2A3P
complex is a high spin complex.
A temperature dependence of the magnetic moment down to
3
.5. Magnetic properties
1.9 K is shown in Fig. 8. As can be seen form the Fig. 8, the
is constant in the temperature range of 300–75 K and below
. This value
l
eff
A plot of the reciprocal molar susceptibility versus temperature
(75 K) drastically decreases to the value of ꢁ3.7
l
B
for MnPc(2A3P) ꢀ 2A3P solid state sample is shown in Fig. 7. The
indicates that below 75 K the MnPc(2A3P) ꢀ 2A3P complex is
corrections for diamagnetic susceptibility of the phthalocyani-
the intermediate-spin complex with the three unpaired electron

J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
31
Table 8
Geometry of the hydrogen bonds in the 2:1 co-crystal of 2A3P: 1,2-DCB.
D–HꢂꢂꢂA
D–H (Å)
HꢂꢂꢂA (Å)
DꢂꢂꢂA (Å)
<(DHA), (°)
N2–H21ꢂꢂꢂN21
N22–H221ꢂꢂꢂN1
N22–H222ꢂꢂꢂN32
0.86
0.86
0.86
2.30
2.16
2,46
3.096(2)
3.004(2)
3.161(3)
154
166
139
i
Symmetry code: i = x + ½, ꢃy + ½, z ꢃ ½.
o
b
a
c
Fig. 5. View of the molecular arrangement of 2(2A3P):(1,2-DCB).
c
b
per molecule (
B
leff spin-only = 3.87 l for S = 3/2). Below 15 K the
Fig. 3. View of the molecular packing of M(II)Pc(2A3P) ꢀ 2A3P (M(II) = Mg, Mn, Zn).
leff quickly decreases to the value close to 0 at the1.9 K. In the
2
+
crystal, the magnetic Mn ions are separated by 7.142(2) and
9
.836(2) in the back-to-back and face-to-face oriented
Å
MnPc(2A3P) ꢀ 2A3P molecules, respectively. These distances are
too large for direct interactions of the 3d orbitals of Mn2+ to mag-
netic exchange phenomenon. Therefore, the possibility of spin–
2
+
spin coupling between the magnetic centres (Mn ) via exchange
mechanism involving electron system of Pc macrocycles should
be considered. The distance of 3.532(3) Å between the N
C5
p
C4
4
ꢂꢂꢂN
4
isoindole planes of the back-to-back oriented and partially
overlapped phthalocyaninate(2-) macrocycles is sufficient to en-
sure the co-operative interactions yielding to antiferromagnetic
C6
N1
C3
C1
2
+
orientation of the magnetic moment of the Mn ions that are
responsible for quick decreasing of the eff at the temperature
close to 1.9 K. For a comparison, the effective magnetic moment,
eff, for the parent non-ligated MnPc complex at room tempera-
ture is equal to 4.33 [30] and is greater than spin-only mag-
netic moment for S = 3/2 (3.87 ) due to a mixing of the
ground state configuration of (b2g) (e
g g
excited state of (b2g) (e ) (a1g)1(b1g) , i.e. E or by a standard
perturbation treatment mixing into the ground term via spin–or-
bit coupling [31]. In addition quite different temperature depen-
C2
l
H221
N2
N22
l
C21
C23
C35
C22
l
B
H21
C36
C31
l
B
N21
C26
2
2
1
4
C34
C33
g
) (a1g) , i.e.
A2g with the
1
2
1
4
C37
C32
C38
N32
C24
dence of the
decreasing of the temperature from 300 to ꢁ15 K the increasing
of was observed. Barroclough et al.
eff from 4.33 to ꢁ7.30
31] explain the increasing of the eff by the ferromagnetic inter-
actions. Below 15 K the eff for pure MnPc decreases to the value
. Thus the observed magnetic properties for the
leff for MnPc was observed (see Fig. 8). With
N31
C25
l
l
B
[
l
l
of ꢁ3.10
l
B
Fig. 4. Asymmetric unit of 2(2A3P):(1,2-DCB) co-crystal. Displacement ellipsoids
are shown at the 50% probability level. H atoms are shown as spheres with arbitrary
radii. Dashed lines represent the hydrogen bonds.
MnPc(2A3P) ꢀ 2A3P complex are different in relation to the par-
ent MnPc complex.

3
2
J. Janczak et al. / Journal of Molecular Structure 937 (2009) 25–33
MgPc(2A3P)x2A3P
1
00
8
6
4
2
0
0
0
0
0
0
50
100
150
200
250
300
300
400
500
600
700
800
Temperature [K]
Wavelength [nm]
Fig. 7. Plots of inverse molar susceptibility of MnPc(2A3P) ꢀ 2A3P solid sample
versus temperature.
MnPc(2A3P)x2A3P
8
7
MnPc(2A3P)x2 A 3 P
6
5
4
3
2
1
0
MnPc
300
400
500
600
700
800
Wavelength [nm]
ZnPc(2A3P)x2A3P
0
50
100
150
200
250
300
Temperature [K]
Fig. 8. Temperature dependence of the magnetic moment of MnPc(2A3P) ꢀ 2A3P
and its parent MnPc complex.
3
00 and 75 K the MnPc(2A3P) ꢀ 2A3P complex is high-spin com-
plex while below 75 K it is intermediate-spin complex.
Supplementary materials
3
00
400
500
600
700
800
Details on data collection and refinement, fractional atomic
coordinates, anisotropic displacement parameters and full list of
bond lengths and angles in CIF format has been deposited at the
Cambridge Crystallographic Data Centre, No. CCDC 719152, CCDC
Wavelength [nm]
Fig. 6. Electronic absorption spectra of MgPc(2A3P) ꢀ 2A3P (a), MnPc(2A3P) ꢀ
2
2
A3P (b) and ZnPc(2A3P) ꢀ 2A3P (c) in pyridine solution. For the MnPc(2A3P) ꢀ
A3P the solid line represents the spectrum of starting complex and the dashed line
7
7
19153 and CCDC 719154 for Mg, Mn and Zn complex, and CCDC
19155 for the co-crystal of 2(2A3P) (1,2-DCB). Copies of this infor-
represents the spectrum after one weak.
.
mation may be obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (fax: +44 1223 336 033;
email: deposit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.
ac.uk). CCDC 719152.
4
. Conclusions
Our investigations showed that using 2-amino-3-picoline as
2
ligating molecule containing a steric hindrance, NH group, forces
monoaxially coordination of MgPc and MnPc complexes in contrast
to the unhindered N-hetero aromatic ligands like pyridine or 4-pic-
oline. The central Zn atom of ZnPc complex prefer 4 + 1 coordina-
tion for all N-hetero aromatic ligands (2A3P, py, 4-Mepy). The
M(II)Pc(2A3P) complexes crystallise with 2A3P molecule as sol-
vent. All investigated here complexes are stable in solid. The
MnPc(2A3P) ꢀ 2A3P complex is moderately stable in solution and
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