Synthesis, characterisation and structural investigations of iodine-doped indium(III) and zirconium(IV) diphthalocyanines: [InPc2]I2 and [ZrPc2]I2

Article abstract of DOI:10.1016/S0020-1693(01)00627-2

Crystals of iodine-doped indium(III) and zirconium(IV) diphthalocyanines, [InPc₂]I₂ and [ZrPc₂]I₂, were grown directly in the reaction of In-Tl alloy or zirconium powder with 1,2-dicyanobenzene under a stream of iodine at about 200°C. Both partially oxidised diphthalocyaninato complexes crystallise in the P4/mcc space group of the tetragonal system with one molecule per unit cell. The space group of P4/mcc requires that the central metal ions are disordered in these structures. The crystal structures shown columnar pseudo-one-dimensional stacks of [InPc₂] or [ZrPc₂] units with a non-integral charge and linear chains of symmetrical triiodide I₃^- ions, which were detected by a Raman spectroscopy. The pseudo-one-dimensional aggregates of [InPc₂]^2/3+ or [ZrPc₂]^2/3+ as well as the chains of I₃^- ions are aligned along the [001] direction. The formal oxidation state of the Pc macrorings equals to ? -1.167 and ? -1.667 in indium(III) and zirconium(IV) diphthalocyaninato complexes. The EPR measurement shows a single sharp EPR line at g = 2.0028 and 2.0026 for the indium and zirconium complexes, respectively. The conductivity measurement on polycrystalline samples at room temperature equals 2.7-3.1 × 10^-2 and 5.2-5.5 × 10^-2 Ω^-1 cm^-1 for [InPc₂]I₂ and [ZrPc₂]I₂, respectively. The charge transport proceeds mainly along the pseudo-one-dimensional [MPc₂]^2/3+ aggregates. Both iodine-doped metallodiphthalocyaninato complexes exhibit non-metallic character in conductivity (dσ/dT > 0).

Full text of DOI:10.1016/S0020-1693(01)00627-2

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Inorganica Chimica Acta 325 (2001) 85–93
Synthesis, characterisation and structural investigations of
iodine-doped indium(III) and zirconium(IV) diphthalocyanines:
[InPc2]I2 and [ZrPc2]I2
Jan Janczak a,b,*, Ynara Marina Idemori a
a Instituto de Cieˆncias Exatas, Departamento de Qu´ımica, Uni6ersidade Federal de Minas Gerais, CEP 31270-901 Belo Horizonte—MG, Brazil
b Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw, Poland
Received 27 April 2001; accepted 14 August 2001
Abstract
Crystals of iodine-doped indium(III) and zirconium(IV) diphthalocyanines, [InPc2]I2 and [ZrPc2]I2, were grown directly in the
reaction of In–Tl alloy or zirconium powder with 1,2-dicyanobenzene under a stream of iodine at about 200 °C. Both partially
oxidised diphthalocyaninato complexes crystallise in the P4/mcc space group of the tetragonal system with one molecule per unit
cell. The space group of P4/mcc requires that the central metal ions are disordered in these structures. The crystal structures
shown columnar pseudo-one-dimensional stacks of [InPc2] or [ZrPc2] units with a non-integral charge and linear chains of
symmetrical triiodide I3− ions, which were detected by a Raman spectroscopy. The pseudo-one-dimensional aggregates of
[InPc2]2/3+ or [ZrPc2]2/3+ as well as the chains of I3− ions are aligned along the [001] direction. The formal oxidation state of the
Pc macrorings equals to $ −1.167 and $ −1.667 in indium(III) and zirconium(IV) diphthalocyaninato complexes. The EPR
measurement shows a single sharp EPR line at g=2.0028 and 2.0026 for the indium and zirconium complexes, respectively. The
conductivity measurement on polycrystalline samples at room temperature equals 2.7–3.1×10−2 and 5.2–5.5×10−2
V
−1 cm−1
for [InPc2]I2 and [ZrPc2]I2, respectively. The charge transport proceeds mainly along the pseudo-one-dimensional [MPc2]2/3+
aggregates. Both iodine-doped metallodiphthalocyaninato complexes exhibit non-metallic character in conductivity (d|/dT\0).
© 2001 Published by Elsevier Science B.V.
Keywords: Indium(III) and zirconium(IV) diphthalocyanine; Sandwich-type metallodiphthalocyanine; EPR spectroscopy; Raman spectroscopy;
Electronic spectra; Conductivity
clearly shows its paramagnetic character and a free
unpaired electron has also been detected by EPR spec-
1. Introduction
troscopy [5]. However, the crystal structure analysis of
the a1-ErPc2 [4] and InPc2 [5] shows that both halves of
these sandwich-type complexes are equivalent struc-
turally, thus no integral formal oxidation state should
be assigned to either of them (z= −1.5). In the second
category doped metal(III) and metal(IV) diphthalo-
cyaninato complexes the conductivity depends strongly
on the amount of the doped atoms, which is closely
correlated with the formal oxidation state of the ph-
thalocyaninato macrocyclic rings. For example, in
a-[PrPc2]Br1.5 [6], a-[SmPc2]Br1.45 [8b] and in [BiPc2]I1.5
[9] the formal oxidation state of the Pc moieties equal
to $ −1.25, while in the [YbPc2]I2 the formal oxida-
tion state of Pc macrorings equals to $ −1.167 [11].
Partially oxidised metallodiphthalocyaninato com-
plexes are divided into two subgroups: (1) undoped
metal(III) diphthalocyanines (Scheme 1(a)) [1–5] and
(2) doped (by I, Br or another monovalent ions such as
ClO4− or BF4−) metal(III) and metal(IV) diphthalocya-
nines (Scheme 1(b)) [6–12]. In the first category
M(III)Pc2, exhibiting semiconducting properties, the
trivalent central metal ion is surrounded by two differ-
ent ligands: Pc2− and one-oxidised Pc− radical ion.
’
For example, the magnetic susceptibility measurement
of the InPc2 complex with one free unpaired electron
* Corresponding author.
E-mail address: jjanek@dedaluss.lcc.ufmg.br (J. Janczak).
0020-1693/01/$ - see front matter © 2001 Published by Elsevier Science B.V.
PII: S0020-1693(01)00627-2

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J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
The formal oxidation state of Pc macrocycles in the
iodine-doped metal(IV) diphthalocyanine complexes
such as [TiPc2]I2 [7] and [UPc2]I2 [12] equals to −1.667,
whereas in the [UPc2]I5/3 the formal oxidation state of
Pc macrocyclic rings equals to −1.722 [10]. The further
oxidation of above mentioned semiconducting metal-
lodiphthalocyaninato complexes leads to the Mott–
Hubbard isolator (Scheme 1(c)) in which, similar to the
lithium phthalocyanine (LiPc) the formal oxidation
state of the Pc ring equals to −1 (Scheme 1(d)) [13].
Understanding of the charge transport in these par-
tially oxidised materials requires the knowledge of their
‘ionicity’ or degree of partial oxidation. The resonance
Raman and 129I Mo¨ssbauer spectroscopy as well as
diffuse X-ray scattering technique offer a simple means
of characterising the polyiodine species [14]. Extensive
theoretical and experimental investigations suggest two
pathways for the charge transport. The high conductiv-
ity of these iodine-doped metallodiphthalocyaninato
complexes can be explained by: (1) the strong interac-
tion of the neighbouring p-ligand orbitals, as in organic
molecular metals [15] with the charge propagation
through p–p orbitals of the macrocyclic rings; and (2)
linear-chain metal spine conductors that propagate
charge through the metal character a1g (d2z) orbitals [16].
Recently, we have reported the synthesis, structure
and some properties of a new iodine-doped complexes
with the composition of [YbPc2]I2 and [(AsPc)(Pc)]I2
[11]. Although the As complex can be described as
[AsPc2]I2 (with the same general formula as other
metallodiphthalocyaninato complexes—[MPc2]I2) the
X-ray and EPR investigations clearly shows that the
crystals of iodine-doped As–phthalocyaninato complex
are built up from two different partially oxidised com-
ponents: the arsenic phthalocyanine units (AsPc) and
phthalocyaninato rings, and linear chains of symmetri-
cal triiodide ions [11].
The majority of the known iodine-doped metal-
lodiphthalocyaninato complexes crystallise in the space
group P4/mcc of the tetragonal system. The [UPc2]I2 is
a unique example of iodine-doped metallodiphthalo-
cyaninato complexes, since it crystallises not in P4/mcc
but in the P4/nnc space group [12]. Thus the iodine-
doped uranium(IV) diphthalocyanine complex—
[UPc2]Ix depends on the crystallisation conditions
and/or on the amount of iodine that could be formed
from two different crystallographic modifications
([UPc2]I5/3—P4/mcc and [UPc2]I2—P4/nnc). The main
difference between these modifications could be found
in the disorder of the central metal (uranium) atom
[10,12].
The aim of our work is to obtain in the crystalline
form a new iodine-doped metal(III) and metal(IV)
diphthalocyanine complexes with the same index of
iodine atom, and find the correlation between the crys-
tal structures and their properties. The elemental analy-
sis of the obtained iodine-doped indium(III) and
zirconium(IV) diphthalocyaninato complexes shows
that in both complexes the relation M/I is equal to 1:2,
thus both complexes can be described as [InPc2]I2 and
[ZrPc2]I2.
2. Experimental
2.1. Preparation
All reagents were of the highest grade commercially
available and were used as received. The crystals of
[ZrPc2]I2 were obtained directly by the reaction of the
pure powdered zirconium and 1,2-dicyanobenzene un-
der a stream of iodine. The powdered zirconium, 1,2-di-
cyanobenzene and iodine in a molar proportion of
1:8:2, with about 5% excess of iodine, were mixed
together and pressed into pellets. The pellets were in-
serted into an evacuated glass ampoule and sealed. The
ampoule was heated at 200 °C for about 6 h. At this
temperature (200 °C), the liquid 1,2-dicyanobenzene
undergoes catalytic tetramerisation forming the ph-
thalocyaninato skeleton which accepts the electrons
from zirconium forming the ZrPc2 complex. Simulta-
neously the iodine atoms (as an oxidant) partially oxi-
dised the ZrPc2 molecules yielding good quality
Scheme 1.
Scheme 2.

J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
87
black–violet single crystals of [ZrPc2]I2 (Scheme 2). The
crystals of [InPc2]I2 were obtained under the same
conditions, but indium–thallium alloy was used in the
reaction. The elemental analysis of both compounds
has been carried out in an energy dispersive spectrome-
ter. Found for zirconium complex: C, 56.20; H, 2.36; I,
18.57; N, 16.32; Zr, 6.58%, and for indium complex: C,
55.11; H, 2.24; I, 18.25; In, 8.28; N, 16.12%. Calc. for
C64H32N16I2Zr: C, 56.11; H, 2.35; I, 18.52; N, 16.36; Zr,
6.66% and calc. for C64H32N16I2In: C, 55.16; H, 2.31; I,
18.21; In, 8.24; N, 16.08%.
The subsequent refinement of the crystal structures
using the SHELXL-97 program [19] with anisotropic
temperature parameters for all non-hydrogen atoms
(for H atoms the Uiso=1.2Uiso, i.e. 20% higher than the
carbon atom directly bonded the H atom) showed that
iodine atom have high anisotropic thermal parameters.
Especially, the anisotropic thermal parameter along the
[001] direction (U33) is about three times larger than its
perpendicular. The final difference Fourier maps
showed no peaks of chemical significance. The final
agreement factor and details of the data collection are
listed in Table 1. Selected bond lengths and angles are
summarised in Table 2.
2.2. X-ray data collection
The single crystals of [ZrPc2]I2 and [InPc2]I2 with
dimensions of 0.15×0.10×0.10 mm and 0.28×0.10×
0.10 mm, respectively, were used for data collection on
a four-circle KUMA KM-4 diffractometer equipped
with a two-dimensional area CCD detector. The
graphite monochromatised Mo Ka radiation (u=
2.4. UV–Vis spectroscopy
Measurements of the electronic spectra of both com-
plexes were carried out at room temperature using a
Cary-Varian 2300 spectrometer. The UV–Vis spectra
were recorded from solution in DMSO in 0.5 cm quartz
cell.
,
0.71073 A) and ꢀ-scan technique with the Dꢀ=0.75°
for one image were used for data collection. The 960
images for six different runs covering over 96% of the
Ewald sphere were performed. Initially the lattice
parameters were refined on 155 (for the Zr complex)
and 144 (for the In complex) reflections obtained from
40 images for eight runs with different orientations in
the reciprocal space. Finally the lattice parameters were
refined by least-squares method on the basis of all
collected reflections with F2\2|(F2). One image was
monitored as a standard after every 40 images. Integra-
tion of the intensities, correction for Lorentz and polar-
isation effects were performed using a KUMA KM-4
CCD software [17]. Systematic absences were observed
for the reflections hhl and 0kl with l odd, consistent
with the space group of P4/mcc or P4cc. Successive
refinement of these structures confirmed the choice of
D24h—P4/mcc as a correct space group. The face-in-
dexed analytical absorption was calculated using the
SHELXTL program [18]. A total of 10 823 (942 indepen-
2.5. Raman spectroscopy
The Raman spectra were recorded at room tempera-
ture in a Jobin-Yvon Ramanor U-1000 spectrometer
equipped with a photomultiplier-type detector and
phonon-counting hardware. The 90° geometry was
used. An argon-ion laser line at 514.5 nm, of power 100
mW, was used as the exciting radiation. Resolution was
set up to 3 cm−1
.
2.6. Electron paramagnetic resonance measurements
Quantitative EPR studies were carried out on solid
state samples of [ZrPc2]I2 and [InPc2]I2. For both com-
plexes the EPR spectra were recorded at room tempera-
ture
using
X-band
microwave
frequencies:
SE-Radiopan and ESR 300 E—Bruker spectrometers.
The g factor and the line width of the signals were
determined. A nuclear magnetometer, frequency coun-
ter and the EPR standards were used to calculate the g
parameter and magnetic field calibration. Quantitative
techniques were used (2–10 mg samples, quartz tubes
of constant volume, constant modulation amplitude 0.1
G, microwave power of 0.2 mW, etc.). The concentra-
tion of the free radicals in the samples were calculated
using standard integration of the derivative signal and
by comparing the area of the free radical EPR signal
with the area determined with the free radical standard.
DPPH, TEMPO, TEMPOL free radicals and Rickitt’s
ultramarine were used as standards for the calculation
of the spin concentration. A single EPR line at g=
2.0026 (Y:6.6 G) and at g=2.0028 (Y:7.1) was
observed for the Zr and In complexes, respectively. The
calculation of the spin concentration results 4.27×1019
dent, Rint=0.0343) and 9177 (825 independent, Rint
=
0.0321) reflections were integrated for the crystals of the
Zr and In complexes, respectively.
2.3. Structures’ determination and refinement
Both structures were solved by the Patterson heavy-
atom method. The Patterson maps revealed the posi-
tions of the Zr and I (or In and I) atoms at the
positions of (1/2, 1/2, 1/4) and (0, 0, 1/4) for the metal
(Zr or In) and iodine atoms, respectively. The space
group of P4/mcc requires that the metal ion is statisti-
cally distributed over two equivalent positions. The
remaining atoms were located from difference Fourier
synthesis. The hydrogen atoms of the phenyl rings were
introduced in their computed coordinates (HFIX 43).

88
J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
Table 1
Crystal data and structure refinement parameters for [InPc2](I3)2/3 and [ZrPc2](I3)2/3
Empirical formula
Molecular weight
Crystal system
C64H32N16I2In
1393.68
tetragonal
P4/mcc
C64H32N16I2Zr
1370.08
tetragonal
P4/mcc
Space group
Unit cell dimensions
,
a (A)
13.984(2)
6.393(1)
1250.2(3)
1
13.941(2)
6.487(1)
1260.8(3)
1
,
b (A)
3
,
V (A )
Z
Dcalc (g cm−3
)
1.851
1.805
Dobs (measured,
floatation)
1.85
1.80
(g cm−3
)
Radiation, Mo Ka
0.71073
0.71073
,
(A)
Index ranges
Reflections collected 9177
−185h518, −175k517, −55l58
−145h519, −195k519, −85l58
10 283
Independent
825 [Rint=0.0321]
942 [Rint=0.0343]
reflections
Observed reflections 623
742
Absorption
1.773
1.507
coefficient, v
(mm−1
)
Correction
Lorentz, polarisation, face-indexed analytical absorption,
min=0.6367, Tmax=0.8427
Lorentz, polarisation, face-indexed analytical absorption,
Tmin=0.8063, Tmax=0.8647
T
Refinement on F2
R (F2\|)
0.0428
0.0805
0.0640
0.0655
wR (F2 all
reflections)
Goodness-of-fit, S
Largest Z/|
1.175
0.002
1.276
0.002
Residual electron
+0.242, −0.461
+0.570, −0.766
−3
,
density (e A
)
R=ꢀꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀFo. wR(F2)={ꢀ(w(Fo2−Fc2)2]/ꢀwFo4}1/2. w−1=[|2(Fo2)+(0.0398P)2] for the In complex and w−1=[|2(Fo2)+1.8268P)] for the
Zr complex where P=(Fo2+2Fc2)/3.
spins/g (:0.099 spins per molecule) and 8.12×1019
spins/g (:0.185 spins per molecule) for [InPc2]I2 and
[ZrPc2]I2 complexes, respectively.
(water, acetone, and alcohol) and are slightly soluble in
DMF or DMSO as well as in aromatic solvents like
chloronaphthalene or quinoline. However, after several
days from the solution in DMSO black powder materi-
als were obtained. The elemental analysis of these pow-
der materials is consistent with the non-iodinated
sandwich complexes—InPc2 and ZrPc2. Thus it was
found that the decomposition process of [MPc2]I2
(M=In, Zr) to MPc2 and I2 takes place in the solution.
This process strongly depends on the temperature, and
takes place several times quicker in hot solvents. Con-
tact with dilute acids led to the demetallation yielding
the a-form of metal-free phthalocyanine (H2Pc) [21]
and appropriate salts. Using pure indium instead of the
In–Tl alloy in the preparation procedure could only
yield iodine monophthalocyanine indium complex—In-
PcI, in which the iodine atom is directly joined to the
central indium metal [22]. Similar observations have
been noticed during the preparation of non-iodinated
sandwich and homoleptic triple-decker indium(III) ph-
thalocyaninato complexes—InPc2 and In2Pc3. Both
complexes could be obtained if the indium alloy was
used in the reaction [5,23].
2.7. Conducti6ity measurements
Conductivity measurements were carried out on the
several polycrystalline compacted samples pressed into
pellets (ꢀ105 kPa) by using a standard four-point
probe technique [20] with a sampling current of 20 mA
at room temperature and with decreasing temperature.
Variation of the temperature was achieved by placing
the samples in a cool-gas stream of N2.
3. Results and discussion
Our preparation method of iodine-doped indium(III)
and zirconium(IV) diphthalocyanines is fast and simple.
Additionally, this method directly leads to obtain a
good quality single crystals. Both the complexes ob-
tained are not soluble in any of the usual solvents

J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
89
Refinement of the crystal structures of both the In
and Zr iodine-doped diphthalocyaninato complexes es-
tablished that the central metal ion similarly as in the
crystal structure of titanium analogue [7] is statistically
distributed over two symmetrically equivalent positions
(1/2, 1/2, 1/4) and (1/2, 1/2, 3/4). Additionally, we
stated that the iodine-doped atoms occupy besides the
Table 2
,
Selected bond lengths (A) and bond angles (°)
[InPc2](I3)2/3
Bond lengths
InꢀN2
N1ꢀC1
N2ꢀC1
N2ꢀC8
C1ꢀC2
C2ꢀC3
C3ꢀC4
C4ꢀC5
C5ꢀC6
[ZrPc2](I3)2/3
2.522(2)
1.323(3)
1.363(4)
1.357(4)
1.475(4)
1.374(4)
1.383(5)
1.388(5)
1.394(4)
1.376(4)
1.441(4)
1.339(4)
ZrꢀN2
N1ꢀC1
N2ꢀC1
N2ꢀC8
C1ꢀC2
C2ꢀC3
C3ꢀC4
C4ꢀC5
C5ꢀC6
C6ꢀC7
C7ꢀC8
C8ꢀN1i
2.527(3)
1.324(3)
1.367(5)
1.368(5)
1.454(5)
1.379(5)
1.381(6)
1.396(7)
1.377(6)
1.400(6)
1.446(6)
1.329(6)
C6ꢀC7
C7ꢀC8
C8ꢀN1i
Fig. 2. View of the partially oxidised of: (a) [InPc2]2/3+ and (b)
[ZrPc2]2/3+ units and labelling scheme. Displacement ellipsoids are
shown at the 50% probability level.
Bond angles
N2ꢀInꢀN2i
N2ꢀInꢀN2ii
N2ꢀInꢀN2iii
N2ꢀInꢀN2iv
N2ꢀInꢀN2v
N2ꢀInꢀN2vi
N2ꢀInꢀN2vii
N2ꢀInꢀN2viii
149.3(1)
66.3(1)
86.7(1)
91.0(1)
141.9(1)
101.4(1)
50.7(1)
129.3(1)
N2ꢀZrꢀN2i
N2ꢀZrꢀN2ii
N2ꢀZrꢀN2iii
N2ꢀZrꢀN2iv
N2ꢀZrꢀN2v
N2ꢀZrꢀN2vi
N2ꢀZrꢀN2vii
N2ꢀZrꢀN2viii
149.1(2)
65.7(1)
88.0(1)
91.6(1)
142.6(2)
100.2(1)
50.1(1)
129.9(1)
special position (0, 0, 1/4) also the (0, 0, z) position,
since the refinement of both structures with the iodine
atom only at the special position of (0, 0, 1/4) gave a
high anisotropic temperature factor (U33 for iodine
atom) and therefore the structure refinement using the
model as schematically presented in Fig. 1(c) was also
checked. The parameter z of the iodine-doped atom
equals 0.238(3) and 0.234(3) in iodine-doped In and Zr
diphthalocyanine structures, respectively. Thus iodine
atoms as dopands in these structures are disordered.
Additionally, in contrast to the crystal structure of
[TiPc2]I2 in which all atoms of the Pc rings are statisti-
cally distributed over two symmetrically equivalent po-
sitions [7] in these crystals of iodine-doped In and Zr
diphthalocyanines all atoms of the Pc rings are ordered.
The molecular structure of partially oxidised indium
and zirconium diphthalocyaninato units is shown in
Fig. 2(a) and (b). Both Pc macrocyclic rings of the
MPc2 units (M=In, Zr) similarly as in the crystal
structure of [BiPc2]I1.5 [9], [UPc2]I5/3 [10] and [YbPc2]I2
[11] are closely planar, since they lie on the site symme-
try of 8m. In other partially oxidised metallodiphthalo-
cyanines the Pc macrorings are not closely planar. For
example, the vertical displacement of the outermost
atoms from the plane defined by four isoindole nitrogen
Symmetry code: (i) 1−y, 1−x, 1/2+z; (ii) 1−y, x, z; (iii) y, x,
1/2−z; (iv) x, 1−y, 1/2+z; (v) 1−x, y, 1/2−z; (vi) 1−x, 1−y, −z;
(vii) y, 1−x, −z; (viii) 1−x, 1−y, 1−z.
Fig. 1. Model of the disorder of the symmetrically triiodide chains in
[MPc2](I3)2/3 (M=In, Zr). Average positions, z=1/4 and equivalent
positions, (a) great anisotropic temperature factor (U33). The three
distinct orderings of the symmetric I3− ions (that are disordered
(translated)) with c%=3/2c are shown in (b), and the statistical
disorder of the polyiodide chains is shown in (c).
,
atoms equals to 0.356 A in [CePc2](BF4)0.33 [8a] and to
,
0.63 A in [SmPc2](ClO4)0.64 [8b] and correlate well with
the diameter of the anionic part of the complexes. The
In3+ (and Zr4+) ion is sandwiched between two par-
tially oxidised macrocyclic Pc rings. The rings are stag-

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J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
form oppositely charged one-dimensional chains which
are parallel to the c-axis. Both crystal structures shown
in Fig. 3 are statistically built up from two real units,
which are presented as (a) and (b) also in Fig. 3.
The resonance Raman spectra of polycrystalline sam-
ples of both complexes measured at room temperature
are similar, exhibit a sharp fundamental band at ꢀ109
cm−1, with an overtone progression of bands at ꢀ220
and ꢀ330 cm−1 (Fig. 4). This pattern is characteristic
for compounds containing the linear chains of symmet-
rical triiodide ions [26–28]. The absence of any peaks
with observable intensities at ꢀ160 or ꢀ180 cm−1
eliminates I5− ion or I2 molecule coordinated to a
Lewis base I3− (I2–I3−), as a predominant iodine form.
The absence of a band at ꢀ200 cm−1 eliminates the
free I2 molecule as an impurity. Also, there is no
evidence in the spectrum of [InPc2]I2 and [ZrPc2]I2 for
the presence of alternative iodine aggregates such as
I42− [29], I5− [30], I7− [31] or I82− [32]. The assignment
of the iodine species as I3− in both (In, Zr) diphthalo-
cyaninato complexes implies a +2/3 formal oxidation
state for [InPc2] and [ZrPc2] units; so these complexes
can be better formulated as [InPc2](I3)2/3 and
gered by 40.0(1)° (in the In complex) and 40.6(1)° (in
the Zr complex) with respect to each other, forming a
distorted square antiprism. In both iodine-doped com-
plexes the MꢀNisoindole (M=In, Zr) bond lengths are
,
longer by ꢀ0.2 A (see Table 3) than those observed in
the non-iodinated indium and zirconium diphthalocya-
nine complexes [5,24]. This is likely due to the weaker
interaction (attraction forces) between the central metal
ion (In3+, Zr4+) with the less negatively (partially
oxidised by iodine) conjugated p-electron macrocyclic
ligands. The CꢀC and CꢀN bond distances and angles
of phthalocyaninato ring for chemically equivalent
bonds do not differ significantly and correlate well with
bond lengths and angles in other metallophthalocya-
nine structures.
The structure of [InPc2]I2 and [ZrPc2]I2 consists of
pseudo-mono-dimensional columnar stacks of partially
oxidised [MPc2]2/3+ units with their molecular Pc
planes normal to the c-axis and separated by c/2. Thus
,
the interplanar Pc–Pc distance of about 3.2 A is shorter
,
than the van der Waals distance of 3.4 A for aromatic
carbon atoms [25] which indicates that the carbon
atoms between the phthalocyaninato planes are inter-
acting. The iodine-doped atoms are located in the chan-
nels between the partially oxidised [MPc2]2/3+ units
[ZrPc2](I3)2/3
,
where one electron per 3/2 MPc2
molecules has been transferred to the I3− counter ion.
Table 3
Comparison of the coordination of the central ion in the iodine-doped and undoped indium(III) and zirconium(IV) diphthalocyaninato complexes
Compound
Formal oxidation state of Pc macroring
[InPc2](I3)2/3
−1.167
InPc2
−1.5
[ZrPc2](I3)2/3
−1.667
ZrPc2
−2
,
MꢀN (A)
2.523(2)
3.196(1)
40.0(1)
2.333(9)
2.741(9)
42.2(4)
2.527(3)
3.244(1)
40.6(1)
2.30
2.52
42.0
[24]
,
Distance between N-isoindole plane (A)
Rotation of the Pc rings (°)
Reference
this work
[5]
this work
Fig. 3. Crystal structure of [MPc2]I2 (M=In, Zr) viewed perpendicular to the macrocycle stacking direction. (a) and (b) are shown at the 50%
probability level.

J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
91
and zirconium diphthalocyanine crystals the diffuse
X-ray scattering lines were not able to be indexed on
,
the basis of a superlattice spacing of about 9.6 A (3/2c),
which is typical of a triiodide superlattice containing
the iodine-doped metallomonophthalocyanine as
NiPc(I3)1/3 [35] or Ni(tbp)(I3)1/3 [36], since the diffuse
lines are slightly modulated. This fact indicates that
there is a small degree of the three-dimensional order,
and therefore both crystal structures have been deter-
mined on the basis lattice. Earlier we reported that
besides the iodine-doped complexes containing symmet-
rical triiodide ions (I3−), the iodine-doped atoms can
form unsymmetrical I3− ions in the metallophthalocya-
nines structures as in MoOPcI3 [37] or in SbPcI3 [38] as
well as can form a neutral molecule of I2, which is a
bridge for a dimerisation or for developing a polymeric
form of mono-and diiodometallophthalocyanine com-
plexes [39,40].
Fig. 4. Resonance Raman spectra of polycrystalline sample of
[MPc2]I2 (M=In, Zr) at room temperature.
The EPR spectrum on the solid samples of
[InPc2](I3)2/3 and [ZrPc2](I3)2/3 at room temperature ex-
hibits a single signal at g=2.0028 and 2.0026, respec-
tively. For a comparison, the EPR spectrum of the
undoped InPc2 complex also shows single signal with a
slightly lowered g parameter (2.0025) [5]. Since both
central cations in these complexes are closed-shell dia-
magnetic (In3+ (d10) and Zr4+ (d0)) ions, we suggest
that both complexes are ligand-centred p radicals. Inte-
gration of the EPR signals results only ꢀ0.099 and
ꢀ0.185 spins per [InPc2](I3)2/3 and [ZrPc2](I3)2/3
molecule, respectively. These values are significantly
lower than the values postulated by Raman spec-
troscopy. For better understanding of the lowered EPR
signal, the partial oxidation process may be described
as postulated from Raman experiment:
Consequently the one Pc macrocyclic ring would have
the formal oxidation state of −1.167 (−7/6) and
−1.667 (−5/3) in the indium and zirconium diph-
thalocyaninato complexes, respectively, since the crystal
structure analysis shown that both Pc macrorings of the
MPc2 unit in these structures are identical in bond
lengths and angles. Recently, for understanding the
nature of the bonding in the I3− ion, i.e. electron-rich
three-centre bonding in more details, the theoretical
calculations using the qualitative molecular orbitals
theory have been performed [33]. The I–I2 bonding
energy in the symmetrical triiodide I3− ion was calcu-
lated to be 37.5 kcal mol−1. The calculated charge on
the two terminal iodine atoms equals to −0.418 while
the central iodine has only charge of −0.163. The IꢀI
bond lengths in the I3− ion calculated on the basis of
the optimised geometry of the I3− ion (Dꢁh) equal to
’
’
’
3[In3+Pc2−Pc− ]+3I2“{[In3+Pc− Pc−
]
’
’
’
[In3+Pc− Pc− ][In3+Pc2−Pc− ]}(I3)2
,
,
ꢀ3.14 A and are approximately 0.3 A longer than the
IꢀI bond length in optimised neutral diiodine (I2)
and similarly for Zr complex:
,
molecule (2.86 A) [33]. The IꢀI bond lengths in the
3[Zr4+Pc2−Pc2−]+3I2
symmetrical I3− ion in both crystal structures are simi-
’
“[Zr4−Pc2−Pc− ][Zr4+Pc2−Pc2−](I3)2
,
lar and equal to 3.046(6) and 3.042(6) A in the In and
Zr diphthalocyaninato complexes, respectively. These
values correlate with the optimised ones if we take into
For the In complex it should be stated that in the first
two units [In3+Pc− Pc ] the electrons could interact
−
’
’
,
account the IꢀI bond length of 2.715(6) A in pure
with each other, which gives S=0. The third unit
[In3+Pc2−Pc− ] with one unpaired electron is EPR
iodine in solid state (at −163 °C) [34] that is shorter
’
,
by about 0.1 A than those in the optimised gas-phase I2
molecule.
active, thus one free unpaired electron per three [InPc2]
units should be given about 0.33 spins per [InPc2](I3)2/3
molecule. For the zirconium complex the first two
From both X-ray and Raman investigations we con-
cluded that iodine-doped atoms in both (In and Zr)
crystals form ordered chains of symmetrical triiodide
I3− ions, that are disordered (translated) with respect to
their neighbour as schematically illustrated in Fig. 1.
This conclusion is consistent with the diffuse X-ray
scattering lines observed in the planes perpendicular to
the stacking direction. In both iodine-doped indium
[Zr4+Pc2−Pc− ] units contain unpaired electron that
’
give about 0.66 spins per [ZrPc2](I3)2/3 molecule. The
distinctly lowered spins concentration observed in the
EPR experiments can be explained by a strong interac-
tion between the Pc− radical, since the interplanar
’
spacing between the Pc planes is relatively short, ꢀ3.2
,
A for both complexes.

92
J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
in the spectrum of [InPc2]I2 complex in DMSO lies at
The electronic absorption spectra of both complexes
ꢀ688 nm (the other bands lie at about 575, 630 and
750 nm) while in the spectrum of [ZrPc2]I2 complex it
lies at 632 nm (the other bands lie at about 573, 686
and 750 nm). The Q band is assigned to the excitation
between the HOMO A1g ground state ((a21u) (p)) and the
degenerate LUMO ((eg) (p*))—the first excited state.
Several authors reported [42] that the splitting value of
Q band (ꢀ60 nm) decreases as the interplanar Pc–Pc
distance increases. Additionally, Takahashi et al. [43]
reported that as interplanar distance lengthens, the
intensity of the Q1 band decreases and that of Q2
increases. As can be seen from the X-ray structure
analysis the interplanar Pc–Pc distance in the complex
recorded in DMSO are similar in the spectral region of
B-Soret band (Fig. 5(a) and (b)), but they differ in the
region of Q band. The B-Soret band is centred at about
355 nm for both complexes, and corresponds well with
the transition observed in other metallodiphthalocyan-
inato complexes [41]. In the spectral region 550–800
nm we observe four bands. The most prominent band
,
of [InPc2]I2 is shorter by about 0.05 A than that found
in the zirconium analogue. Thus in the spectrum of
indium diphthalocyaninato complex we attributed the
bands at ꢀ688 and ꢀ630 nm to Q1 and Q2 bands,
respectively. The equivalent Q1 and Q2 bands in the
spectrum of the zirconium complex lie at ꢀ686 and
ꢀ633 nm. The inversion of the intensities of the Q1 and
Q2 bands and the splitting value of ꢀ58 nm (in the
spectrum of [InPc2]I2) and ꢀ53 nm (in the spectrum of
[ZrPc2]I2) correlate well with the X-ray experiment.
The electrical conductivities of [InPc2](I3)2/3 and
[ZrPc2](I3)2/3 at room temperature measured on several
samples are equal to 2.7–3.1×10−2 and 5.2–5.5×
10−2
V
−1 cm−1, respectively. With decreasing of the
temperature the conductivity also decreases, thus both
iodine-doped complexes exhibit non-metallic character
in conductivity (d|/dT\0). The conductivity at
liquid nitrogen (ꢀ78 K) is smaller by about two order.
These data have been obtained on compressed poly-
crystalline samples and suffer from interparticle contact
resistance effects and from being averaged over all
crystallographic orientations. The charge propagation
mainly proceeds along the pseudo-mono-dimensional
[MPc2]2/3+ aggregates. During charge transport there is
no need to change the population distribution among
the sites, since both crystals of iodine-doped diphthalo-
cyaninato complexes with closed-shell (d10 or d0)
metal(III) or metal(IV) cation contain partially oxidised
phthalocyaninato macrorings (as was evidenced by
EPR spectroscopy). Thus the jumping of the electron
from one side to another with the pre-formed hole
takes place between isoenergetic configuration (Scheme
3). Nevertheless, the powder and single-crystal data for
other ‘molecular metals’ indicate that single-crystal con-
ductivities along the molecular stacking direction is
greater by a factor of 102–103 [35].
Fig. 5. Electronic spectra of [InPc2]I2 (a) and [ZrPc2]I2 (b) in DMSO.
4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Scheme 3.

J. Janczak, Y.M. Idemori / Inorganica Chimica Acta 325 (2001) 85–93
93
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