How big is big? Separation by conventional methods, X-ray and electronic structures of positional isomers of bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato ir

Article abstract of DOI:10.1142/S1088424616500164

A presence of bulky 2,6-di-iso-propylphenoxy groups in bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex allows separation of two individual pos

Full text of DOI:10.1142/S1088424616500164

Journal of Porphyrins and Phthalocyanines
J. Porphyrins Phthalocyanines 2016; 20: 1–15
DOI: 10.1142/S1088424616500164
Published at http://www.worldscinet.com/jpp/
How big is big? Separation by conventional methods, X-ray
and electronic structures of positional isomers of bis-tert-
butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-
3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-
phthalocyaninato iron(II) complex
Derrick R. Anderson, Pavlo V. Solntsev, Hannah M. Rhoda and Victor N. Nemykin*◊
Department of Chemistry & Biochemistry, University of Minnesota Duluth, 1039 University Drive,
Duluth, MN 55812, USA
Dedicated to Professor Kevin M. Smith on the occasion of his 70th birthday
Received 23 November 2015
Accepted 16 December 2015
ABSTRACT: A presence of bulky 2,6-di-iso-propylphenoxy groups in bis-tert-butylisocyano adduct of
2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phtha-
locyaninato iron(II) complex allows separation of two individual positional isomers and a mixture of
the remaining two isomers using conventional chromatography. X-ray structures of “D2h” and “C4h”
isomers were confimed by X-ray crystallography. Density functional theory (DFT) and time-dependent
DFT (TDDFT) calculations of each individual positional isomer allowed insight into their electronic
structures and vertical excitation energies, which were correlated with the experimental UV-vis and
MCD spectra.
KEYWORDS: iron phthalocyanine, positional isomers, X-ray crystallography, UV-vis, MCD, density
functional theory, time-dependent density functional theory.
solubilities of phthalocyanine molecules but also
INTRODUCTION
adjusts their photophysical, redox, and aggregation
Phthalocyanines are a well-known class of organic
properties [9]. Because of the well-known application
compounds which is widely used as dyes and pigments
of iron phthalocyanines in catalysis [10], a lot of
[1] as well as high tech applications such as optical
attention was focused on the preparation of well soluble
recording [2], optical limiting [3], catalysis [4],
iron phthalocyanines with relatively high first oxidation
photodynamic therapy of cancer [5], liquid crystalline
potentials. In order to increase the solubility of the iron
materials [6], materials for light harvesting [7], and bio
phthalocyanine in common organic solvents, one might
imaging [8]. Because of the low solubility of standard
think about peripheral substituents with bulky aryl
unsubstituted phthalocyanine complexes, there is a
or alkyl groups, which will both prevent aggregation
continuous effort to improve synthetic strategies for
and increase the solubility of target molecules. One
the preparation of substituted phthalocyanines. Indeed,
of the most popular strategies for the introduction of
peripheral substitutions as well as axial coordination
such groups is the aromatic nucleophilic substitution
through the central metal allows not only to tune the
of the nitro or chloro group(s) with aryloxo or
arylthiol substituents [9]. Although this strategy is
very simple and useful for the creation of symmetric,
◊ SPP full member in good standing
octa-substituted phthalocyanines, the presence of
eight electron-donating groups on the periphery of the
*Correspondence to: Victor N. Nemykin, email: vnemykin@d.
umn.edu, fax: +1 218-726-7394, tel: +1 218-726-6729
Copyright © 2016 World Scientific Publishing Company

2
D. R. ANDERSON ET AL.
macrocycle results in a significant decrease of the first
oxidation potential of the phthalocyanine core, which
is not a desirable property for oxidative chemical
catalysis. It has been shown that the presence of both
halogens and aryloxo groups at the periphery of the
phthalocyanine macrocycles allows the achievement
of both oxidative stability and the solubility of the
macrocycles [11]. In a series of publications originating
from McKeowns group, it has been shown that the
2,3,9,10,16,17,23,24-octa(2,6-di-iso-propylphenoxy)
phthalocyanines can form highly unusual cubic
symmetry crystals with large nano-scale voids accessi-
ble for a variety of small substrate molecules [12].
Although such crystals can be directly used in catalytic
transformations of organic substrates, it is expected
that they will have a relatively low stability due to the
eight electron-donating groups. Thus, in this paper we
prepared 2(3),9(10),16(17),23(24)-tetrachloro-3(2),
10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-
phthalocyaninato iron(II) in which four electron
acceptor chlorine groups should stabilize the energy
of the HOMO orbital and thus improve potential
catalytic properties of this iron macrocycle. Because
of the asymmetric nature of precursor, 4-chloro-
5-(2,6-di-iso-propylphenoxy)phthalonitrile, the target
phthalocyanine is expected to be formed as a statistical
mixture of four positional isomers (Scheme 1).
Thus, our second aim was to study whether or not is
possible to separate the individual positional isomers
using standard chromatography techniques as it was
mentioned before that the separation of similar metal-
free, zinc, aluminum, gallium, and indium complexes
by column chromatography or high performance liquid
chromatography (HPLC) is very difficult [13].
OAr
ArO
i-Pr
OAr
ArO
OH
N
Cl
Cl
CN
CN
ArO
ArO
CN
CN
i-Pr
N
N
N
N
1. FeCl2
L
Fe
L
N
N
2. t-BuNC
K2CO3/DMSO
120 °C
2
N
OAr
OAr
i-Pr
ArO
ArO
OH
i-Pr
K2CO3/DMSO
90 °C
OAr
Cl
ArO
Cl
4
OAr
Cl
Cl
ArO
N
N
ArO
Cl
CN
1. FeCl2
N
N
N
N
N
N
N
N
L
Fe
L
L
Fe
L
2. t-BuNC
CN
N
N
N
N
1
N
N
OAr
Cl
Cl
Cl
Cl
OAr
Cl
ArO
Cl
ArO
Cl
i-Pr
*
3a
3b
O
ArO =
OAr
i-Pr
Cl
OAr
ArO
ArO
N
N
L = t-BuNC
N
N
N
N
N
N
N
N
L
Fe
L
L
Fe
L
N
N
N
N
N
N
OAr
OAr
ArO
ArO
Cl
Cl
Cl
Cl
3c
3d
Scheme 1. Synthesis of nitriles 1 and 2 and phthalocyanines 3 and 4
Copyright © 2016 World Scientific Publishing Company
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HOW BIG IS BIG? SEPARATION BY CONVENTIONAL METHODS, X-RAY AND ELECTRONIC STRUCTURES
3
RESULTS AND DISCUSSION
Synthesis and attempted separation of individual
positional isomers
The degree of nucleophilic substitution in
4,5-dichlorophthalonitrile by 2,6-di-iso-propylphenol
depends on the reaction temperature. Thus, when the
reaction was conducted in DMSO at 120°C, in the
presence of excess phenol, the major reaction product
was 4,5-(2,6-di-iso-propylphenoxy)phthalonitrile with a
minor presenceof 4-chloro-5-(2,6-di-iso-propylphenoxy)
phthalonitrile. When the reaction was conducted at
70°C in acetonitrile or DMF or at 90°C in DMSO,
the major reaction product was 4-chloro-5-(2,6-di-iso-
propylphenoxy)phthalonitrile contaminated by a small
amount of 4,5-(2,6-di-iso-propylphenoxy)phthalonitrile.
A template reaction of the 4-chloro-5-(2,6-di-iso-
propylphenoxy)phthalonitrile in the presence of iron
salt after the standard reaction mixture workup followed
by interaction of the crude product with a large excess
of tert-butylisonitrile as a axial ligand, resulted in the
formation of axially coordinated by tert-butylisonitrile
2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),
24(23)-tetra(2,6-di-iso-propylphenoxy)phthalocyaninato
iron(II) complex 3 as a mixture of all four positional
isomers 3a–3d (Scheme 1). Target blue-colored product
is stable in a solid state and solution, as expected, but
sensitive to the photophysical dissociation of the axial
ligand, which is similar to the earlier reported compounds
[14]. To our surprise, both analytical and preparative
aluminum plates allow separation of three fractions of 3
(Fig. 1).WewereabletoconfirmbyX-raycrystallography
discussed below that the first and the third fractions
correspond to the “C4h” and “D2h” individual isomers 3a
and 3d, respectively, while the most abundant second
fraction consists of a mixture of the two remaining “C2v”
and “Cs” positional isomers. Thus, at least in our hands,
we were able to separate two pure fractions of positional
isomers 3a and 3d and thus one can conclude that, at
least for the phthalocyanines with in-plane central ion
the presence of bulky 2,6-di-iso-propylphenoxy groups,
separation of individual isomers can be achieved by
conventional chromatography methods.
Fig. 1. Photograph of separation of individual isomers of
complex 3
Fig. 2. High-resolution ESI mass spectrum of 3
Spectroscopy
The UV-vis spectra of fractions 1–3 in Q-band region
are virtually the same, indicating that the influence of the
asymmetric pattern of peripheral substituents on the energy
splitting between the LUMO and LUMO+1 energy levels
is rather small. Such a small energy difference between
LUMO and LUMO+1 was further supported by DFT
calculations on the individual isomers 3a–3d and indicative
of the effective four-fould symmetry in these isomers.
The B-band in the UV-vis spectrum of 3 was observed at
343 nm and is more intense in comparison to the Q-band
at 665 nm due to the contributions from the four peripheral
The high-resolution ESI mass spectrum of the mixture
of positional isomers 3 is shown in Fig. 2. It is dominated
by three major peaks which correspond to the [M]+, [M +
THF + O]+, and [M + THF + O2]+ ions. In addition, low
intensity ions which originate from a loss of one or two
axial ligands were also observed in ESI mass spectrum at
the lower masses. The molecular ion isotope distribution
and mass of the [M]+ are in excellent agreement with the
simulated pattern. The UV-vis and MCD spectra of the
mixture of the positional isomers 3 is present in Fig. 3.
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D. R. ANDERSON ET AL.
from the twelve signals for α-phthalocyanine protons
between 9.0 and 9.4 ppm (6 singlets) and 7.9–8.3 ppm
(6 singlets). In addition, two diastereotopic isopropyl
C–H signals were observed between 3.1 and 3.5 ppm.
Finally, several multiplets which correspond to the
terminal methyl groups in 3 were observed in the 1H NMR
of the reaction mixture. In contrast, in the case of pure
fraction 3 (which corresponds to “D2h” isomer 3d), only
one signal of α1-phthalocyanine and α2-phthalocyanine
as well as only one signal from C–H isopropyl groups
1
have been observed in H NMR spectrum (we were not
able to get a good quality 1H NMR of fraction 1 due to its
small quantities), Fig. 4.
X-ray crystallography
The X-ray structures of nitriles 1 and 2 as well as
individual isomers of phthalocyanine 3a and 3d are
shown in Figs 5–8 while the important crystallographic
information (refining parameters, crystallographically
determined distances and bond angles) are listed in
Tables 1 and 3. The asymmetric nitrile 1 crystalizes in P1
symmetry unit cell with two unique molecules per cell,
while symmetric nitrile 2 crystallizes in hexagonal space
group R-3 and a single unique nitrile molecule per unit
cell. In addition, a solvent water molecule has been seen
on the inversion center of the unit cell in the structure of
nitrile 2. In both nitriles, the 2,6-di-iso-propylphenoxy
group are almost perpendicular to the molecular plane
of the dicyanobenzene fragment thus eliminating any
conjugation between the substituents and the core
aromatic ring. The C≡N, C–Cl, and C–O bond distances
are in the typical range. Nitrile 1 has a very clear 2D
intermolecular packing motif which originates from
CN—Cl and CN—H intermolecular interactions. CN—
Cl contacts range between 3.262 and 3.293 Å, while the
CN—H close contacts range between 2.590 and 2.596
Å (Fig. 5). In both cases, close contacts are smaller than
the sum of the Van der Waals radius of corresponding
atoms. There are no such clear structural motifs in the
case of the packing in the symmetric nitrile 2 observed
by X-ray crystallography. The 3D structure of nitrile 2
predetermined by CN—H and CH—C intermolecular
contacts, which are expected to be weak compared to the
CN—Cl contacts seen in nitrile 1. The X-ray structures
of the individual isomers 3a and 3d are shown in Figs 7
and 8. Fraction 1 consists of the “C4h” isomer 3a, which
crystallizes in monoclinic P21/c space group and has
iron center located at the crystallographic center of
symmetry. Fraction 3 consists of the “D2h” isomer 3d,
which crystalizes in the triclinic P-1 space group and has
two independent molecules in a unit cell. The iron center
is located at the center of symmetry in each individual
molecule. In the case of individual positional isomers
3a and 3d, the first coordination sphere of the iron
center resembles the previously published bis isonitrile-
coordinated iron phthalocyanines [14]. In particular, the
Fig. 3. UV-vis and MCD spectra of 3 in DCM
2,6-di-iso-propylphenoxy groups. In addition, a weak
band around 415 nm was observed in the UV-vis spectrum
of the target compound 3. This low-intensity band is
associated with the very weak MCD Faraday A-term and,
based on the similarity with the energy of earlier reported
phthalocyanine iron(II) complexes axially coordinated
with organic isonitriles, was assigned to the metal to
ligand charge transfer (MLCT) band originating from
the excitation from the Fe dxz, dyz MOs to phthalocyanine
centered p* orbital [14]. The MCD spectrum of 3 is
dominated by the Faraday MCD A-term centered at
663 nm which corresponds to the UV-vis absorption peak
at 665 nm. In addition, another prominent Faraday MCD
A-term has been observed at 342 nm, which corresponds to
the UV-vis peak at 343 nm. As expected for Fe (dxz, dyz) →
Pc (p*) MLCT transition, the MCD A-term observed
at ~415 nm is very weak. Overall, the position of
Q- and B-bands in 2(3),9(10),16(17),23(24)-tetrachloro-
3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphen-
oxy)phthalocyaninato iron(II) complex is typical for the
bis-axially coordinated by two isonitrile ligands iron
phthalocyanines except for the large intensity B-band
in the UV-vis spectrum, which reflects the presence of
four additional phenoxy groups in our compound. It
is also worthwhile to note that the UV-vis spectrum of
phthalocyanine 3 and, in particular its Q- and B-band
positions (665 and 343 nm), is very close to that observed
in the reported earlier [12a] symmetric analogue 4 (Q-band
at 664 and B-band at 349 nm [12a]).
1
The H NMR spectra of the reaction mixture as well
as fraction 3 are similar to each other on a qualitative
level. The presence of four positional isomers on the
NMR spectra of the reaction mixture can be clearly seen
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5
Fig. 4. 1H NMR spectrum of positional isomer 3d. Solvent impurities are labeled with asterisk
Fig. 5. X-ray structure of nitrile 1 (a), two crystallographically independent molecules in the unit cell) and its packing diagram (b)
Copyright © 2016 World Scientific Publishing Company
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D. R. ANDERSON ET AL.
ligands have close-to-linear geometry and a typical
Fe–C and C≡N bond distances. Simillar to nitriles 1 and
2, the 2,6-di-iso-propylphenoxy groups in 3a and 3d
are almost perpendicullar to the phthalocyanine plane.
Although isomer 3a has small voids which are occupied
by dichloromethane solvent, both molecules do not
have nanometer scale channels which were observed
in X-ray structures of the symmetric octa-substituted
phthalocyanine 4. Thus, one can conclude that the
presence of chlorine substituents in phthalocyanines
3a–3d results in a disruption in the hydrophobic
isopropyl-to-isopropyl groups interactions observed in
the case of symmetric octa-substituted phthalocyanine
4. We were also able to grow the crystal structure of
phthalocyanine 4 and determine that the unit cell of the
complex was almost indistinguishable with the crystal
structure published by McKeown and coworkers [12].
Fig. 6. X-ray structure of nitrile 2
first coordination sphere of the iron center resembles a
distorted octahedral environment with the axial Fe–C
bond distances being shorter compared to the equatorial
Fe–N bond distances (Table 1). The phthalocyanine
ligands are planar in 3a and 3d. The axial isonitrile
Electronic structures and vertical excitation energies
of individual positional isomers 3a–3d
The insight into the electronic structure and vertical
excitation energies of individual positional isomers 3a–3d
Fig. 7. X-ray crystal structure of positional isomer 3a. (a) General view; (b) core structure; (c) packing diagram
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HOW BIG IS BIG? SEPARATION BY CONVENTIONAL METHODS, X-RAY AND ELECTRONIC STRUCTURES
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Fig. 8. X-ray crystal structure of positional isomer 3d. (a) General view of two crystallographically independent molecules in the
unit cell; (b) packing diagram
was gained on the basis of density functional theory
(DFT) and time-dependent DFT (TDDFT) calculations.
The energy diagram for 3a–3d is shown in Fig. 9, the
selected frontier orbitals are listed in Fig. 10, and the
frontier molecular orbital contributions are presented in
Table 2. The DFT-predicted electronic structures of the
individual positional isomers 3a–3d are very close to each
other and correlate well with the observed PcFe(CNR)2
complexes optical and redox properties [14]. In particular,
the HOMO, LUMO, and LUMO+1 MOs in 3a–3d are
phthalocyanine-centered, which correlate well with the
electrochemical data on similar systems. A compression
of the octahedral environment along C–Fe–C z-axis
results in higher energies of predominantly Fe-centered
dxz (HOMO-1) and dyz (HOMO-2) MOs compared to the
Fe-centered dxy (HOMO-3) orbital. In the case of isomers
3a and 3c, LUMO and LUMO+1 are degenerate, while
a small splitting (up to 0.08 eV) of these orbitals was
predicted for isomers 3b and 3d. The classic Gouterman’s
orbitals [15] in isomers 3a–3d were identified as HOMO,
HOMO-6, LUMO, and LUMO+1, which correspond to
the “a1u”, “a2u”, and “eg” type orbitals in Gouterman’s D4h
point group notation.
In order to get insight in the optical spectroscopy of the
individual isomers 3a–3d, we have conducted TDDFT
calculations, which were proven to provide reliable
assignments of the UV-vis spectra of transition-metal
phthalocyanines and in particular PcFeL2 complexes
[16]. The TDDFT-predicted UV-vis spectra for isomers
3a–3d along with experimental spectrum of 3 are
shown in Fig. 11. From Fig. 11, it is clear that TDDFT-
predicted UV-vis spectra of 3a–3d correlate well with
an experimental spectrum of 3. Because of its actual
Ci symmetry, “C4h” isomer 3a is the only individual
isomer, which has “gerade” and “ungerade” orbitals,
1
which simplifies analysis of TDDFT data as only Au
symmetry excited states will have non-zero intensities.
In agreement with the UV-vis spectra of PcFe(CNR)2
complexes [14], the visible region of UV-vis spectrum
of 3a is dominated by two nearly degenerate excited
1
states 1 and 2 of Au symmetry, which are dominated
by the classic Gouterman’s “a1u → eg” in common D4h
point group notation (HOMO → LUMO and HOMO →
LUMO+1) single-electron excitations. Similarly, the
most intense band in UV region of the UV-vis spectrum
of 3a is dominated by the nearly degenerate excited
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D. R. ANDERSON ET AL.
Table 1. Selected bond lengths and bond angles for nitriles 1, 2, and complexes 3a and 3d
1
C(21)≡N(22)
C(23)≡N(24)
Cl(1)-C(2)
C(3)-O(4)
1.146 (7)
1.146 (7)
1.717 (6)
1.360 (6)
92.58 (6)
C(29)≡N(30)
1.134 (7)
1.140 (7)
1.731 (5)
1.364 (6)
114.04 (7)
C(47)≡N(48)
Cl(25)-C(26)
C(33)-O(34)
C(2)-C(3)-C(5)-C(6)
C(26)-C(33)-C(35)-C(36)
2
C(19)≡N(20)
1.151 (3)
1.364 (3)
81.95 (3)
C(23)≡N(24)
1.146 (3)
1.369 (3)
102.68 (3)
O(1)-C(2)
O(4)-C(3)
C(3)-C(2)-C(25)-C(26)
C(2)-C(3)-C(5)-C(6)
3a
Fe(1)-N(2)
1.955 (5)
1.907 (6)
171.2 (7)
86.7 (2)
Fe(1)-N(6)
1.950 (5)
1.131 (8)
169.1 (6)
92.5 (2)
Fe(1)-C(50)
C(50)≡N(51)
C(1)-N(5)-C(52)
N(2)-Fe(1)-C(1)
C(27)-C(13)-C(15)-C(16)
Fe(1)-C(50)-N(5)
N(6)-Fe(1)-C(1)
C(33)-C(35)-C(38)-C(39)
132.99 (7)
125.97 (6)
3d
Fe(1)-N(1)
1.941 (3)
1.935 (3)
175.0 (4)
88.60 (13)
132.61 (9)
1.950 (3)
1.924 (4)
172.2 (4)
85.80 (14)
73.88 (8)
Fe(1)-N(2)
1.929 (3)
1.137 (4)
174.0 (3)
91.39 (13)
115.79 (8)
1.939 (3)
1.157 (5)
169.9 (3)
89.73 (13)
73.80 (7)
Fe(1)-C(1)
C(1)≡N(5)
C(1)-N(5)-C(52)
N(1)-Fe(1)-C(1)
C(13)-C(15)-C(18)-C(19)
Fe(2)-N(6)
Fe(1)-C(1)-N(5)
N(2)-Fe(1)-C(1)
C(33)-C(35)-C(38)-C(39)
Fe(2)-N(7)
Fe(2)-C(2)
C(2)≡N(10)
C(2)-N(10)-C(107)
N(6)-Fe(2)-C(2)
C(68)-C(70)-C(73)-C(74)
Fe(2)-C(2)-N(10)
N(7)-Fe(2)-C(2)
C(88)-C(90)-C(93)-C(94)
states 20 and 21 of 1Au symmetry, which originate
from the Gouterman’s “a2u → eg” in common D4h point
group notation (HOMO-6 → LUMO and HOMO-6 →
LUMO+1) single-electron excitations. Finally, TDDFT
predicts that the MLCT band in 3a, which predominantly
originates from the Fe (dxz, dyz) → Pc (p*) single-electron
transitions should be located at 319 nm (1Au symmetry
excited states 46 and 47). Although TDDFT-predicted
energy for these transitions is overestimated from the
experimentally observed for 3 MCD Faraday A-term
at ~415 nm, such energy overestimation is typical for
CT states predicted by B3LYP exchange-correlation
functional [16]. Nevertheless, agreement between
TDDFT-predicted and experimental UV-vis spectra of
3a is quite good. Since actual symmetries of positional
isomers 3b–3d are C2 and C1, parity rule for excited
states in these systems does not apply anymore, which
results in numerous weak CT transitions predicted by
TDDFT in visible region of their spectra. Since MCD
Fig. 9. DFT-predicted molecular orbital energy diagram for
positional isomers 3a–3d
spectrum of 3 is clearly indicative of the high-symmetry
excited states, which result in observation of the MCD
Faraday A-terms, such MLCT transitions should have
negligible intensities as the Fe-centered dxz, dyz, and dxy
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9
were obtained from Aldrich Co. DCM and acetonitrile
were dried and distilled over CaH2. DMF and DMSO
were dried over molecular sieves (4 Å) for 24 h prior use.
4,5-Dichlorophthalonitrile, 2,6-di-iso-propylphenol, and
potassium carbonate were obtained from Aldrich Co. and
were used as received.
Physical measurements
Jasco-720 spectrophotometer was used to collect
UV-vis data. OLIS DCM 17 CD spectropolarimeter
with a 1.4 T DeSa magnet was used to collect MCD
data. The MCD spectra were measured in mdeg = [q]
and converted to De (M-1.cm-1.T-1) using the regular
conversion formula. Complete spectra were recorded at
room temperature in parallel and antiparallel directions
1
with respect to the magnetic field. H and 13C NMR
spectra were recorded using Varian ANOVA instrument
with 500 MHz frequence for protons. High-resolution
ESI MS data were collected using Bruker microTOF-III
instrument and THF as a solvent.
Computational aspects
All DFT calculations were conducted using the
Gaussian 09 software package [17] running under either
Windows or UNIX OS.All positional isomers 3a–3d were
optimized at the DFT level using the B3LYP exchange-
correlation functional [18]. Wachter’s full electron basis
set [19] for iron and 6–31G(d) basis sets [20] for all other
atoms. The PCM method [21] was used to calculate the
solvent effects for all DFT and TDDFT calculations
using DCM as a solvent. In all calculations, tight energy
(10-8 au) SCF convergence criterion has been used.
Molecular orbital composition analysis was conducted
using QMForge program [22]. TDDFT calculations were
conducted for the 80 lowest energy excited states.
X-ray analysis
X-ray quality crystals of nitriles 1 and 2 were obtained
by slow evaporation of methanol/DCM mixtures. Dark
blue crystals of complexes 3a and 3d were obtained by
Fig. 10. DFT-predicted profiles of selected frontier orbitals of 3a
slow evaporation of DCM/hexane solution. All X-ray
diffraction data were collected on Rigaku RAPID-II
diffractometer using either Mo-Kα (l = 0.71073 Å) or
Cu-Kα (l = 1.54187 Å) radiation selected by graphite
monochromator at -150°C. Structures were solved by
direct method implemented into SIR92 software [23] and
refined by full-matrix least square method using Crystals
for Windows software [24]. All nonhydrogen atoms
were refined anisotropically. Hydrogen atoms were
localized from the difference Fourier map and refined
using a riding mode approximation U(H) = 1.2Ueq(C).
All final refinement parameters are presented in Table 3.
PLATON SQUEEZE program was used for elimination
of the disordered DCM molecule in the structure of 3a
MOs as well as phthalocyanine-centered LUMO and
LUMO+1 should have “gerade” character.
EXPERIMENTAL
Materials
A symmetric iron phthalocyanine complex 4 was
prepared following described earlier procedure [12a].
Dichloromethane (DCM), acetonitrile, DMF, and DMSO
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 9–15

10
D. R. ANDERSON ET AL.
Table 2. DFT-predicted compositions of the frontier MOs for individual isomers 3a–3d
% MO Composition
MO
Energy (eV)
Symmetry
Fe
Pc
tbutyl
Cl
OPh
3a
411
412
413
414
415
416
417
418
-6.238
-6.054
-5.666
-5.663
-4.923
-2.613
-2.61
au
ag
ag
ag
au
ag
ag
au
0.21
68.64
40.41
40.3
0.01
3.88
3.85
0
55.52
31.17
44.36
44.39
92.98
92.27
92.43
90.62
2.08
0
8.73
0.09
3.88
3.86
1.56
1
33.47
0.1
3.57
3.55
0.04
0.19
0.2
7.78
7.89
5.41
2.67
2.51
6.48
1
-1.195
0.01
2.89
3b
411
412
413
414
415
416
417
418
-6.226
-6.046
-5.664
-5.657
-4.916
-2.606
-2.602
-1.147
b
a
a
b
a
a
b
b
0.75
68.6
56.7
31.2
6.82
0
7.3
28.44
0.1
0.09
4.61
3.84
1.47
1.01
1.01
2.4
40.76
40.49
0.17
44.49
44.48
92.8
3.63
3.57
0.01
0.19
0.2
6.51
7.62
5.55
2.64
2.54
7
3.86
92.29
92.4
3.85
0.08
90.49
0.03
3c
411
412
413
414
415
416
417
418
-6.055
-6.048
-5.711
-5.544
-4.931
-2.652
-2.573
-1.175
a
a
a
a
a
a
a
a
10.03
65.42
44.12
29.41
0.13
52.29
32.39
42.68
48.57
93.16
92.7
3.21
0.19
4.15
2.39
0.02
0.19
0.19
0.04
4.01
0.3
30.46
1.69
4.78
18.5
4.64
1.62
3.06
5.36
4.26
1.13
2.05
1.71
0.58
2.86
3.78
3.93
92.22
91.66
0.08
3d
411
412
413
414
415
416
417
418
-6.248
-6.042
-5.681
-5.628
-4.917
-2.628
-2.571
-1.148
b
a
a
b
a
a
b
b
0.79
68.59
41.97
39.78
0
63.58
31.23
43.93
45.05
93.21
92.24
92.31
89.41
8.85
0
7.79
0.09
5.69
2.46
1.61
1.55
0.41
2.43
18.99
0.08
4.54
9.35
5.18
1.82
3.57
7.72
3.86
3.36
0
4.21
3.51
0.17
0.18
0.2
0.27
HOMO and LUMO are in bold.
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 10–15

HOW BIG IS BIG? SEPARATION BY CONVENTIONAL METHODS, X-RAY AND ELECTRONIC STRUCTURES
11
of dry DMSO under argon atmosphere. A light yellow
solution was heated to 90°C for 1 h. Resulting light brown
solution was cooled to the room temperature, poured into
100 mL of water and neutralized by diluted hydrochloric
acid. Precipitate was filtered and recrystallized from
methanol. Yield 1.04 g (61.4%) of a white crystals with
mp 180–182°C. Anal. calcd. for C20H19ClN2O: C, 70.90;
H, 5.65; N, 8.27%. Found C, 70.97; H, 5.75; N, 8.13%.
1H NMR (500 MHz, CDCl3, 20°C): d, ppm 1.11 (d, J =
6.5 Hz, 6H, -CH3), 1.20 (d, J = 6.5 Hz, 6H, -CH3), 2.73
(septet, J = 6.5 Hz, 2H, Ar-CH), 6.73 (s, 1H, Ar-H),
7.29 (d, J = 7.5 Hz, 2H, Ar-H), 7.38 (t, J = 7.5 Hz, 1H,
Ar-H). 13C NMR (125 MHz, CDCl3, 20°C): d, ppm 22.40
(-CH3), 24.42 (-CH3), 27.57 (Ar-CH), 109.18, 114.54,
114.67, 115.59, 118.15, 125.45, 127.95, 128.31, 135.61,
140.66, 147.06, 158.43.
4,5-Bis-(2,6-di-iso-propylphenoxy)phthalonitrile
(2). This compound was prepared by slight modification
ofthereportedearlierprocedure. Drypotassiumcarbonate
(3.00 g, 22 mmol) was added in 8 portions over period of
30 min to a stirred solution of 4,5-dichlorophthalonitrile
Fig. 11. Comparison between experimental UV-vis spectrum of
3 and TDDFT-predicted UV-vis spectra of isomers 3a–3d
(1.00 g, 5 mmol) and 2,6-di-iso-propylphenol (5.34 g,
30 mmol) in 15 mL of dry DMSO under argon
atmosphere. A light yellow solution was heated to 120°C
for 1 h. Resulting pale blue-brown solution was cooled to
the room temperature, poured into 100 mL of water and
neutralized by diluted hydrochloric acid. Precipitate was
filtered and recrystallized from methanol. Yield 1.43 g
[25]. Mercury program was used for packing diagram
generation [26].
Synthesis
1
(59.5%) of a white crystals with mp 160–162°C. H
NMR (500 MHz, CDCl3, 20°C): d, ppm 1.18 (d, J =
5.5 Hz, 6H, -CH3), 1.24 (d, J = 5.5 Hz, 6H, -CH3), 2.95
(septet, J = 5.5 Hz, 2H, Ar-CH), 6.76 (s, 2H, Ar-H), 7.26–
7.35 (m, 3H, Ar-H).
4-Chloro-5-(2,6-di-iso-propylphenoxy)phthalonitrile
(1).
Method A. Dry potassium carbonate (4.0 g, 29 mmol)
was added in 8 portions over period of 8 h to a stirred
solution of 4,5-dichlorophthalonitrile (1.02 g, 5 mmol)
and 2,6-di-iso-propylphenol (1.97 g, 11 mmol) in 80 mL
of dry acetonitrile under argon atmosphere. A light
yellow solution was heated to 70°C for 24 h. Resulting
light brown solution was cooled to the room temperature,
poured into 200 mL of water and neutralized by diluted
hydrochloric acid. The target compound was filtered and
recrystallized from methanol. Yield 0.83 g (47.3%) of a
white crystals with mp 180–182°C.
Method B. Dry potassium carbonate (2.26 g,
16 mmol) was added in 8 portions over period of 30 min
to a stirred solution of 4,5-dichlorophthalonitrile (1.12 g,
5.7 mmol) and 2,6-di-iso-propylphenol (3.04 g, 17 mmol)
in 50 mL of dry DMF under argon atmosphere. A light
yellow solution was heated to 70°C for 1 h. Resulting
light brown solution was cooled to the room temperature,
poured into 200 mL of water and neutralized by diluted
hydrochloric acid. The target compound was filtered and
recrystallized from methanol. Yield 1.24 g (64.4%) of a
white crystals with mp 180–182°C.
2(3),9(10),16(17),23(24)-Tetrachloro-3(2),10(9),
17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)phthalo
cyaninato iron(II) di-tert-butylisocyanide (3). Dry
ferrous chloride (0.16 g, 1.3 mmol) and 4-chloro-5-(2,6-
di-iso-propylphenoxy)phthalonitrile (0.25 g, 0.7 mmol)
were added in one portion to a stirred solution of lithium
N,N-dimethylaminoethoxide (prepared from 8 mg,
1.2 mmol, of Li metal) in 3 mL of dry N,N-dimethyl-
aminoethanol under argon atmosphere. Reaction mixture
was reflux for 2.5 h, cooled to the room temperature,
poured into 20 mL of water, filtered and dried overnight.
Yield of the crude green product is 0.127 g (48.8%).
The crude green product was dissolved in 10 mL of dry
toluene and 1.5 mL of tert-butylisocyanide was added
to the reaction mixture. Reaction mixture was heated
at 50°C for 24 h, solvent and an excess of the axial
ligand were evaporated in vacuum and dried. A small
portion of blue precipitate was filtered through a 5 cm of
alumina using 1:1 (v/v) DCM:hexanes mixture and the
mixture of positional isomers 3a–3d was isolated upon
evaporation of the solvents in vacuum. This sample was
used for UV-vis, MCD, ESI MS, and 1H NMR spectra of
the mixture of positional isomers 3a–3d. The rest of the
blue precipitate was loaded on thin layer chromatography
Method C. Dry potassium carbonate (3.00 g, 22 mmol)
was added in 8 portions over period of 30 min to a stirred
solution of 4,5-dichlorophthalonitrile (1.00 g, 5 mmol)
and 2,6-di-iso-propylphenol (5.34 g, 30 mmol) in 15 mL
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 11–15

12
D. R. ANDERSON ET AL.
Table 3. Crystal data collection and refinement for nitriles 1, 2, and complexes 3a and 3d
Empirical formula
C20H19Cl1N2O1
C32H36N2O2 ·H2O
C90H90Cl4Fe1N10O4
C90H90Cl4Fe1N10O4
Formula weight
Temperature, K
Space group, Z
a, Å
338.84
483.66
1573.43
1573.43
123
123
123
123
P1, 2
R-3, 18
P21/c, 2
P-1, 2
6.28110 (10)
8.49460 (10)
17.1438 (12)
98.929 (7)
98.759 (7)
93.962 (7)
889.05 (7)
1.266
35.808 (2)
35.808 (2)
11.2600 (7)
90
10.0746 (6)
13.7552 (8)
33.739 (2)
90
13.7969 (6)
17.5859 (6)
19.3592 (13)
111.393 (8)
92.374 (7)
99.803 (7)
4282.1 (5)
1.221
b, Å
c, Å
α,°
b,°
90
105.411 (7)
90
g, °
V, Å3
Dcalc, g/cm3
m, mm-1
120
12503.4 (13)
1.156
4507.4 (5)
1.159
1.957 (Cu)
68.213
0.072 (Mo)
26.371
0.338 (Mo)
26.372
0.356 (Mo)
26.370
2qmax, °
GoF(F2)
R1, wR2 [I>2σ(I)]
R1, wR2 [all data]
0.8695
0.9379
0.9845
0.9525
0.0651, 0.1472
0.0827, 0.1573
-0.47, 0.62
0.0638, 0.1694
0.1025, 0.1967
-0.45, 0.78
0.0982, 0.2407
0.1778, 0.3020
-0.88, 1.06
0.0591, 0.1498
0.1022, 0.1912
-0.57, 1.11
r
max/rmin, e/Å3
plates and separated in three blue fraction using 1:1
(v/v) DCM:hexanes mixture as eluent. Three fractions
were collected. The first fraction, based on X-ray
crystallography results, (1.5 mg) was found to be a pure
isomer 3a. A second fraction has a mixture of positional
isomers 3b and 3c (23 mg). The third fractions was
identified by X-ray crystallography as positional isomer
complexes axially coordinated with organic isonitrile
groups and are dominated by the intense Q- and B-bands
as well as low intensity MLCT transitions. Two out of the
four positional isomers (3a and 3d) can be separated using
conventional chromatography methods. The structures of
these two individual positional isomers 3a and 3d were
determined by X-ray crystallography. The central iron
atoms in both cases were observed in distorted octahedral
N4C2 environment with Fe–C bond distances shorter
compared to the Fe–N bond distances. The presence of
the four chlorine substituents of the phthalocyanine core
results in disruptions of the hydrophobic intermollecular
interactions between isopropyl groups. As a result, X-ray
structures of 3a and 3d do not have large solvent-accesable
voids which were observed in symmetric octasubstituted
phthalocyanine 4. Electronic structures of individual
isomers 3a–3d were calculated using the DFT approach
and are very close to each other. The HOMO, LUMO, and
LUMO+1 orbitals are dominated by the contribution from
the phthalocyanine core. The influence of the asymmetric
pattern in 3a–3d on the energy separation between LUMO
and LUMO+1 is rather mild. The TDDFT calculations
predict that the UV-vis absorption spectrum of individual
isomers 3a–3d should be dominated by four strong bands
resultingfromtwopairsofnearly-degenerateexcitedstates.
The first pair of nearly-degenerate states would contribute
into the intensity of the Q-band region and the other pair
of degenerate states would contribute to the intensity of
the B-band region. In addition, TDDFT also correctly
predicts the presence of the MLCT band at ~415 nm
spectral window.
1
3d (4 mg). H NMR for 3d (500 MHz, CDCl3, 20°C):
d, ppm -0.55 (s, 18H, CNC(CH3)3), 1.16 (d, J = 6.5 Hz,
24H, -CH3), 1.36 (d, J = 6.5 Hz, 24H, -CH3), 3.28 (septet,
J = 6.5 Hz, 8H, Ar-CH), 7.43 (d, J = 7.5 Hz, 8H, OAr-H),
7.54 (t, J = 7.5 Hz, 4H, OAr-H), 7.99 (s, 4H, α1-Pc), 9.26
(s, 4H, α2-Pc). 13C NMR (125 MHz, CDCl3, 20°C): d,
ppm 22.58 (-CH3), 24.84 (-CH3), 27.58 (Ar-CH), 28.67
(-C(CH3)3), 31.74 (-C(CH3)3), 105.99, 122.88, 123.38,
124.84, 126.61, 134.94, 140.35, 141.81, 145.63, 146.11,
149.26, 155.31. The isonitrile C≡N carbon signal was not
observed in 13C NMR spectrum, which is typical for this
class of compounds [14, 27].
CONCLUSION
In this paper, we have prepared bis-axially coordi-
nated with tert-butylisonitrile 2(3),9(10),16(17),23(24)-
tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-
iso-propylphenoxy)phthalocyaninato iron(II) complexes
3 which were characterized by UV-visible spectroscopy,
MCD, ESI MS, and 1H NMR spectroscopy. The presence
of all four positional isomers in the reaction mixture was
1
proven by the H NMR spectroscopy. The UV-vis and
MCD spectra of 3a–3d are typical for iron phthalocyanine
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 12–15

HOW BIG IS BIG? SEPARATION BY CONVENTIONAL METHODS, X-RAY AND ELECTRONIC STRUCTURES
13
Supporting information
5. (a) Lukyanets EA. J. Porphyrins Phthalocyanines
1999; 3: 424–432. (b) De Rosa A, Naviglio D and
Di Luccia A. Curr. Cancer Therapy Rev. 2011; 7:
234–247. (c) Bonnett R. Chemical Aspects of Photo-
dynamic Therapy, Gordon and Breach: Amsterdam,
2000. (d) Ali H and van Lier JE. In Handbook of
Porphyrin Science, Vol. 4, Kadish KM, Smith KM
and Guilard R. (Eds.) World Scientific: Singapore,
2010; pp. 1–120.
Crystallographic CIF files for 1, 2, 3a and 3d are given
in the supplementary material. This material is available
free of charge via the Internet at http://www.worldscinet.
com/jpp/jpp.shtml.
Crystallographic data have been deposited at the
Cambridge Crystallographic Data Center (CCDC) under
numbers CCDC 1441635 (1), 1441634 (2), 1441632 (3a),
and 1441633 (3d). Copies can be obtained on request,
free of charge, via www.ccdc.cam.ac.uk/data_request/cif
or from the Cambridge Crystallographic Data Center, 12
Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223-
336-033 or email: data_request@ccdc.cam.ac.uk).
6. McKeown NB. Phthalocyanine Materials: Struc-
ture, Synthesis and Function, Cambridge Univ.
Press: Cambridge, UK, 1998; pp. 200.
7. (a) Chen X, Li C, Graetzel M, Kostecki R and
Mao SS. Chem. Soc. Rev. 2012; 41: 7909–7937.
(b) Harvey PD. In The Porphyrin Handbook, Vol.
18, Kadish KM, Smith KM and Guilard R. (Eds.)
Academic Press: San Diego, 2003; pp. 63–250.
(c) Grimm B, Hausmann A, Kahnt A, Seitz W,
Spanig F and Guldi DM. In Handbook of Porphy-
rin Science, Vol. 1, Kadish KM, Smith KM and
Guilard R. (Eds.) World Scientific: Singapore, 2010;
pp. 133–220. (d) D’Souza F and Ito O. In Handbook
of Porphyrin Science, Vol. 1, Kadish KM, Smith KM
and Guilard R. (Eds.) World Scientific: Singapore,
2010; pp. 307–438. (e) Martinez-Diaz MV and Tor-
res T. In Handbook of Porphyrin Science, Vol. 10,
Kadish KM, Smith KM and Guilard R. (Eds.) World
Scientific: Singapore, 2010; pp. 141–182. (f) Fuku-
zumi S. In Handbook of Porphyrin Science, Vol. 10,
Kadish KM, Smith KM and Guilard R. (Eds.) World
Scientific: Singapore, 2010; pp. 183–244.
8. (a) D’Souza F and Ito O. Chem. Soc. Rev. 2012; 41:
86–96. (b) Harbeck S, Atilla D, Dulger I, Harbeck
M, Gurek AG, Ozturk ZZ and Ahsen V. Sensors
Actuators, B: Chemical 2014; 191: 750–756.
(c) Ben-Hur E and Chan WS. In The Porphyrin
Handbook, Vol. 19, Kadish KM, Smith KM and
Guilard R. (Eds.)Academic Press: San Diego, 2003;
pp. 1–36. (d) Ethirajan M, Patel NJ and Pandey RK.
In Handbook of Porphyrin Science, Vol. 4, Kadish
KM, Smith KM and Guilard R. (Eds.) World Scien-
tific: Singapore, 2010; pp. 249–324.
9. (a) Nemykin VN and Lukyanets EA. ARKIVOC,
2010; (i): 136–208. (b) Nemykin VN and Lukyanets
EA. In Handbook of Porphyrin Science, Vol. 3,
Kadish KM, Smith KM and Guilard R. (Eds.);
World Scientific: Singapore, 2010: pp. 1–323.
(c) Nemykin VN, Dudkin SV, Dumoulin F, Hirel
C, Gurek AG and Ahsen V. ARKIVOC 2014; (i):
142–204. (d) Lukyanets EA and Nemykin VN. J.
Porphyrins Phthalocyanines 2010; 14: 1–40.
10. (a) Sorokin AB, Kudrik EV and Bouchu D. Chem.
Commun. 2008; 2562–2564. (b) Geraskin IM,
Luedtke MW, Neu HM, NemykinVN and Zhdankin
VV. Tetrahedron Lett. 2008; 49: 7410–7412.
(c) Geraskin IM, Pavlova O, Neu HM,Yusubov MS,
Nemykin VN and Zhdankin VV. Adv. Synth. Catal.
Acknowledgements
Generous support from the NSF CHE-1401375,
CHE-1464711, MRI-1420373, MRI-0922366 and the
Minnesota Supercomputing Institute to VN is greatly
appreciated.
REFERENCES
1. (a) Thomas FH and Moser AL. The Phthalocya-
nines: Manufacture and Application, Vol. 2, CRC
Press, Boca Raton, 1983. (b) Wöhrle D. In Phtha-
locyanines: Properties and Applications, Vol. 1,
Leznoff CC and Lever ABP. (Eds.) VCH Publisher,
Inc.: New York, 1989; pp. 55–132. (c) Ferraudi G.
In Phthalocyanines: Properties and Applications,
Vol. 1, Leznoff CC and Lever ABP. (Eds.) VCH
Publisher, Inc.: New York, 1989; pp. 291–340.
(d) Erk P and Henselsberg H. In The Porphyrin
Handbook, Vol. 19, Kadish KM, Smith KM and
Guilard R. (Eds.) Academic Press, San Diego,
2003; pp. 105–150.
2. Hurditch R. Adv. Colour Sci. Technology 2001; 4:
33–40.
3. (a) Jurow M, Schuckman AE, Batteas JD and Drain
CM. Coord. Chem. Rev. 2010; 254: 2297. (b) Flom
SR. In The Porphyrin Handbook, Vol. 19, Kadish
KM, Smith KM and Guilard R. (Eds.) Academic
Press: San Diego, 2003; pp. 179–190. (c) Dini D
and Hanak M. In The Porphyrin Handbook, Vol.
17, Kadish KM, Smith KM and Guilard R. (Eds.)
Academic Press: San Diego, 2003; pp. 1–36.
4. (a) Sorokin AB. Chem. Rev. 2013; 113: 8152–8191.
(b) Isci U, Dumoulin F, Sorokin AB and Ahsen
V. Turk. J. Chem. 2014; 38: 923–949. (c) Sorokin
AB and Kudrik EV. Catalysis Today 2010; 159:
37–46. (c) Kimura M and Shirai H. In The Porphy-
rin Handbook, Vol. 19, Kadish KM, Smith KM and
Guilard R. (Eds.)Academic Press: San Diego, 2003;
pp. 151–178. (d) Wark M. In The Porphyrin Hand-
book, Vol. 17, Kadish KM, Smith KM and Guilard
R. (Eds.) Academic Press: San Diego, 2003;
pp. 247–284.
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 13–15

14
D. R. ANDERSON ET AL.
2009; 351: 733–737. (d) Neu HM, Yusubov MS,
Zhdankin VV and Nemykin VN. Adv. Synth. Catal.
2009; 351: 3168–3174. (e) Neu HM, Zhdankin
VV and Nemykin VN. Tetrahedron Lett. 2010; 51:
6545–6548. (f)Yusubov, M. S.; Celik, C.; Geraskina
M. R.; Yoshimura A.; Zhdankin V. V.; Nemykin, V.
N. Tetrahedron Lett. 2014; 55: 5687–5690. (g) Isci
U, Faponle AS, Afanasiev P, Albrieux F, Briois V,
Ahsen V, Dumoulin F, SorokinAB and de Visser SP.
Chem. Science 2015; 6: 5063–5075. (h) Alvarez LX
and Sorokin AB. J. Organomet. Chem. 2015; 793:
139–144. (i) Colomban C, Kudrik EV, Tyurin DV,
Albrieux F, Nefedov SE, Afanasiev P and Sorokin
AB. Dalton Trans. 2015; 44: 2240–2251. (j)
Colomban C, Kudrik EV, Briois V, Shwarbrick JC,
Sorokin AB and Afanasiev P. Inorg. Chem. 2014;
53: 11517–11530.
(c) Sabin JR, Varzatskii OA, VoloshinYZ, Starikova
ZA, Novikov VV and Nemykin VN. Inorg. Chem.
2012; 51: 8362–72. (d) Maslov VG. Optics Spec-
troscopy 2006; 101: 853–861. (e) Janczak J, Kubiak
R and Lisowski J. J. Porphyrins Phthalocyanines
2013; 17: 742–749. (f) He H, LeiY, Xiao C, Chu D,
Chen R and Wang G. J. Phys. Chem. C 2012; 116:
16038–16046. (g) Silaghi-Dumitrescu R, Makarov
SV, Uta MM, Dereven’kov IA and Stuzhin PA.
New J. Chem. 2011; 35: 1140–1145. (h) Sumimoto
M, Kawashima Y, Hori K and Fujimoto H. Dal-
ton Trans. 2009; 5737–5746. (i) Liao MS, Kar T,
Gorun SM and Scheiner S. Inorg. Chem. 2004; 43:
7151–7161.
17. Gaussian 09, Revision A.1, Frisch MJ, Trucks GW,
Schlegel HB, Scuseria GE, Robb MA, Cheeseman
JR, Scalmani G, Barone V, Mennucci B, Petersson
GA, Nakatsuji H, Caricato M, Li X, Hratchian HP,
Izmaylov AF, Bloino J, Zheng G, Sonnenberg JL,
Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa
J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai
H, Vreven T, Montgomery JA Jr, Peralta JE, Ogli-
aro F, Bearpark M, Heyd JJ, Brothers E, Kudin
KN, Staroverov VN, Kobayashi R, Normand J,
Raghavachari K, Rendell A, Burant JC, Iyengar SS,
Tomasi J, Cossi M, Rega N, Millam JM, Klene M,
Knox JE, Cross JB, Bakken V, Adamo C, Jaramillo
J, Gomperts R, Stratmann RE,Yazyev O, Austin AJ,
Cammi R, Pomelli C, Ochterski JW, Martin RL,
Morokuma K, Zakrzewski VG, Voth GA, Salvador
P, Dannenberg JJ, Dapprich S, Daniels AD, Farkas
O, Foresman JB, Ortiz JV, Cioslowski J, Fox DJ.
Gaussian, Inc., Wallingford CT, 2009.
18. (a) Becke AD. J. Chem. Phys., 1993; 98: 5648. (b)
Lee C,Yang W and Parr RG. Phys. Rev. B 1988; 37:
785.
19. Wachters AJH. J. Chem. Phys. 1970; 52: 1033.
20. (a) Hehre WJ, Ditchfield R and Pople JA. J. Chem.
Phys., 1972; 56: 2257; (b) Gordon MS. Chem. Phys.
Lett., 1980; 76: 163.
21. Tomasi J, Mennucci B and Cammi R. Chem. Rev.
2005, 105: 2999.
22. Tenderholt AL. QMForge, Version 2.1. Stanford
University, Stanford, CA, USA.
23. Altomare A, Cascarano G, Giacovazzo C,
Guagliardi A, Burla MC, Polidori G and Camalli
M. J. Appl. Cryst. 1994; 27: 435.
24. Betteridge PW, Carruthers JR, Cooper RI, Prout K
and Watkin DJ. J. Appl. Cryst. 2003; 36: 1487.
25. Spek AL. Acta Cryst. 2009; D65: 148–155.
26. Mercury 3.0 http://www.ccdc.cam.ac.uk/Solutions/
CSDSystem/Pages/Mercury.aspx
27. (a) Lee FW, Choi MY, Cheung KK and Che CM. J.
Organomet. Chem. 2000; 595: 114. (b) Galardon E,
Lukas M, Le Maux P and Simonneaux G. Tetrahe-
dron Lett. 1999; 40: 2753. (c) Geze C, Legrand N,
Bondon A and Simonneaux G. Inorg. Chim. Acta.
11. (a) Van Haeringen CJ, West JS, Davis FJ, Gilbert
A, Hadley P, Pearson S, Wheldon AE and Henbest
RGC. Photochem. Photobiol. 1998; 67: 407–413.
(b) Fox JP and Goldberg DP. Inorg. Chem. 2003;
42: 8181–8191.
12. (a) Bezzu CG, Helliwell M, Warren JE, Allan DR
and McKeown NB. Science 2010; 327: 1627–1630.
(b) McKeown NB, Makhseed S, Msayib KJ, Ooi
LL, Helliwell M and Warren JE. Angew. Chem., Int.
Ed. 2005; 44: 7546–7549. (c) Bezzu CG, Kariuki
BM, Helliwell M, Tuna F, Warren JE, Allan DR and
McKeown NB. CrystEngComm 2013; 15: 1545–
1550. (d) Makhseed S, Ibrahim F, Samuel J, Helli-
well M, Warren JE, Bezzu CG and McKeown NB.
Chem. Eur J. 2008; 14: 4810–4815.
13. (a) Tuhl A, Chidawanayika W, Ibrahim HM, Al-
Awadi N, Litwinski C, Nyokong T, Behbehani H,
Manaa H and Makhseed S. J. Porphyrins Phthalo-
cyanines 2012; 16: 163–174. (b) Tuhl A, Manaa H,
Makhseed S, Al-Awadi N, Mathew J, Ibrahim HM,
Nyokong T and Behbehani H. Optical Mater. 2012;
34: 1869–1877.
14. (a) Hanack M and Ryu H. Synth. Metals 1992; 46:
113. (b) Ryu H, Knecht S, Subramanian LR and
Hanack M. Synthetic Metals 1995; 72: 289. (c)
Hanack M, Kamenzin S, Kamenzin C and Subrama-
nian LR. Synth. Metals 2000; 110: 93. (d) Hanack
M, Hees M and Witke E. New J. Chem. 1998; 22:
169. (e) Watkins JJ and Balch AL. Inorg. Chem.
1975; 14: 2720. (f) Nemykin VN, Purchel AA, Spa-
eth AD and Barybin MV. Inorg. Chem., 2013; 52:
11004–11012.
15. (a) Gouterman M. J. Mol. Spectrosc. 1961; 6: 138–
163. (b) (b) Gouterman M, Wagnière GH and Sny-
der LC. J. Mol. Spectrosc. 1963; 11: 108–127.
16. (a) Nemykin VN, Kobayashi N, Chernii VY and
BelskyVK. Eur. J. Inorg. Chem. 2001; 733. (b) Mie-
dema PS, van Schooneveld MM, Bogerd R, Rocha
TCR, Haevecker M, Knop-Gericke A and de Groot
FMF. J. Phys. Chem. C 2011; 115: 25422–25428.
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 14–15

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15
1992; 195: 73. (d) Malvolti F, Le Maux P, Toupet L,
Smith ME, Man WY, Low PJ, Galardon E, Simon-
neaux G and Paul F. Inorg. Chem. 2010; 49: 9101.
(e) Galardon E, Le Maux P, Paul C, Poriel C and
Simonneaux G. J. Organomet. Chem. 2001; 629:
145. (f) Nemykin VN, Dudkin SV, Fathi-Rasekh M,
SpaethAD, Rhoda HM, Belosludov RV and Barybin
MV. Inorg. Chem., 2015; 54: 10711–10724.
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 15–15