Synthesis, spectroscopic, and electrochemical studies of 1,2-naphthalene-ring-fused tetraazachlorins, -bacteriochlorins, and -isobacteriochlorins: The separation and characterization of structural isomers

Article abstract of DOI:10.1002/chem.200400845

1,2-Naphthalene-ring-expanded tetraazachlorins (TACs), tetraazabacteriochlorins (TABCs), and tetraazaisobacteriochlorins (TAiBCs) have been synthesized. Procedures for the synthesis of the starting materials, that is, derivatives of 1,2-naphthalene-dicarb

Full text of DOI:10.1002/chem.200400845

FULL PAPER
Synthesis, Spectroscopic, and Electrochemical Studies of 1,2-Naphthalene-
Ring-Fused Tetraazachlorins, -bacteriochlorins, and -isobacteriochlorins:
The Separation and Characterization of Structural Isomers
Elena A. Makarova,[a] Takamitsu Fukuda,[b] Evgeny A. Luk’yanets,*[a] and
Nagao Kobayashi*[b]
Abstract:
1,2-Naphthalene-ring-ex-
lar steric repulsion effect, which was
predicted by geometry optimizations at
the DFT level. The derived compounds
were characterized by using IR, elec-
tronic, and magnetic circular dichroism
(MCD) spectroscopy, and by electro-
chemical methods. Frequency calcula-
tions at the DFT level correctly repro-
duced the experimental IR spectra and,
in particular, distinguished between the
three isomers of the TAiBCs. In the
electronic absorption and MCD spectra
of the TAC and TABC species, the Q-
band splits into two intense compo-
nents similarly to the 2,3-naphthalene-
fused derivatives described in our pre-
ceding paper, although no significant
spectral differences were observed
from species to species. On the other
hand, the spectra of the TAiBCs
showed moderate differences depend-
ing on the structure of the isomer. The
spectroscopic properties as well as the
electrochemical behavior of these
chlorins resemble those of the corre-
sponding benzene-fused derivatives
rather than the 2,3-naphthalene-fused
derivatives. Molecular-orbital and con-
panded tetraazachlorins (TACs), tet-
raazabacteriochlorins (TABCs), and
tetraazaisobacteriochlorins (TAiBCs)
have been synthesized. Procedures for
the synthesis of the starting materials,
that is, derivatives of 1,2-naphthalene-
dicarboxylic acid, have been reinvesti-
gated and improved. Nine possible de-
rivatives, including four, two, and three
structural isomers of TACs, TABCs,
and TAiBCs, respectively, were sepa-
rated by using thin-layer chromatogra-
phy (TLC) or high-performance liquid
chromatography (HPLC), and the
structure of each isomer was deter-
figuration-interaction
calculations
within the framework of the ZINDO/S
method were helpful in the discussions
of the above observations.
Keywords:
density
functional
1
mined by H NMR spectroscopy com-
calculations
·
IR spectroscopy ·
bined with the NOE technique. The
formation ratio of each isomer was ra-
tionalized in terms of the intramolecu-
phthalocyanines · porphyrinoids ·
UV/Vis spectroscopy
Introduction
Tetraazachlorins (TACs), tetraazabacteriochlorins (TABCs),
and their structural isomers, tetraazaisobacteriochlorins
(TAiBCs), which have fused aromatic rings, form a new
family of hydrogenated tetraazaporphyrins (TAPs) and their
unique spectral properties are of interest for a wide range of
applications, in a similar way to phthalocyanines (Pcs).[1–3]
Recently, we developed an approach to the synthesis of
novel benzene- or 2,3-naphthalene-ring-fused TAC, TABC,
and TAiBC derivatives in which mixed condensation of the
corresponding precursors with different hydrogenation
levels successfully yielded all of the possible derivatives;
their synthesis and spectroscopic and electrochemical prop-
erties have been described in detail in our preceding
paper.[4,5] In our on-going studies, this methodology was ex-
[a] Dr. E. A. Makarova, Prof. Dr. E. A. Luk’yanets
Organic Intermediates and Dyes Institute
1/4 B. Sadovaya Str., 103787 Moscow (Russia)
Fax : (+7)095-254-9866
E-mail: rmeluk@co.ru
[b] Dr. T. Fukuda, Prof. Dr. Dr. N. Kobayashi
Department of Chemistry, Graduate School of Science
Tohoku University, Sendai 980–8578 (Japan)
Fax : (+81)22-217-7719
E-mail: nagaok@mail.tains.tohoku.ac.jp
Supporting information (experimental and calculated IR data of 1,2-
NiTNTACs and 1,2-NiDNTABCs) for this article is available on the
WWW under http://www.chemeurj.org/ or from the author.
Chem. Eur. J. 2005, 11, 1235 – 1250
DOI: 10.1002/chem.200400845
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tended to the synthesis of angularly annulated 1,2-naphtha-
lene-ring-fused TACs, TABCs, and TAiBCs, as reported in a
preliminary publication.[6] Although the angular extension
of Pc skeletons was attempted as early as 1936 by Brad-
brook and Linstead,[7] the separation of mixtures of the pos-
sible structural isomers was complicated and could not be
achieved. Hence, the separation and identification of the
structural isomers of Pcs has been one of the most impor-
tant and difficult subjects in the field of low-symmetry Pc
chemistry, although recently a few studies have reported the
isolation of one of the isomers of the 1,2-naphthalocyanines
(1,2-Ncs). For example, Hanack et al. isolated the 1,2-FeNc(-
cyclohexylisocyanide)2 isomer with C4h symmetry from a
mixture of isomers by column chromatography.[8] The syn-
thetic route to the C4h isomer of 1,2-FeNc with bulky sub-
stituents, in which steric effects suppressed the formation of
the other isomers, was developed by the same group.[9] The
first successful separation of all of the possible isomers of
1,2-MgNc by chromatography has been reported recently,
carboxylic anhydride (19), we reinvestigated the Diels–
Alder condensation of a-bromostyrene (17) with maleic an-
hydride (18) in boiling toluene followed by the dehydrogen-
ation of the resultant adduct by using sulfur.[13] We found
that the desired aromatic anhydride was formed directly in
one step when the same condensation was carried out in
boiling trichlorobenzene in the presence of charcoal
(Scheme 2). The best yield (up to 40% after chromatogra-
phy) was achieved when 17 and 18 were used in a 1:3 molar
ratio. Although the yield is lower in our case, the product
contains no sulfur compounds, which are frequently tedious
to remove.
The condensation of the dienophile fumaronitrile (20)
with 17 under similar reaction conditions afforded 1,2-dicya-
nonaphthalene (21) directly in 26% yield. 4-Phenyl-1,2-
naphthalenedicarboxylic anhydride (24) was obtained ac-
cording to the literature procedure[14] by the Diels–Alder
condensation of 1,1-diphenylethylene (22) with 18, followed
by aromatization of the thus formed bis-adduct 23 by heat-
ing with sulfur (Scheme 2).
1
together with their H NMR and UV/Vis spectra.[10] More-
over, two geometrical isomers, namely, 1,2-MgNc with C4h
symmetry and 1,2-CoNc with C2v symmetry, have also been
isolated by fractional crystallization and characterized by X-
ray analysis.[11,12]
Herein we report the synthesis and separation of all the
possible isomers of 1,2-naphthalene-ring-fused TACs,
TABCs, and TAiBCs (1–16,
To synthesize angularly annulated 1,2-TNTAC, 1,2-
DNTABC, and 1,2-DNTAiBC, we used the strategy de-
scribed in our preceding paper[5] for the preparation of simi-
lar types of compounds with fused benzene and linearly an-
nulated naphthalene rings, that is, by mixed condensation of
precursors with different hydrogenation levels. The mixed
Scheme 1), which were ob-
tained by the mixed condensa-
tion of tetramethylsuccinoni-
trile (25) with 1,2-naphthalene-
dicarboxylic acid derivatives
such as the anhydride, imide,
and dinitrile. The isomeric
structures were determined
1
mainly on the basis of their H
NMR data. Spectroscopic and
electrochemical methods, in-
cluding UV/Vis, magnetic circu-
lar dichroism (MCD), IR, and
cyclic voltammetry (CV), as
well as molecular-orbital (MO)
calculations, have revealed the
effect of angular extension of
the aromatic rings.
Results and Discussion
Synthesis: Derivatives of 1,2-
naphthalenedicarboxylic acid,
such as the anhydride, imide,
and dinitrile, were used as start-
ing compounds for the prepara-
tion of 1,2-naphthalene-fused
TACs, TABCs, and TAiBCs. To
synthesize 1,2-naphthalenedi- Scheme 1. Structures and abbreviations of the compounds in this study.
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1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
with toluene and chloroben-
zene, followed by further purifi-
cation and separation by
column chromatography on alu-
mina.
Other derivatives of 1,2-
naphthalenedicarboxylic acid,
such as the anhydride or imide,
can also be employed as start-
ing materials in this reaction
(Scheme 3). Their condensation
with 25 was conducted in boil-
ing sulfolane in the presence of
metal salts and urea, and simi-
larly afforded three new 1,2-
naphthalene-fused compounds
with similar yields to those ob-
tained with 21.
Since all 1,2-naphthalene-
Scheme 2.
fused compounds exist as
a
mixture of structural isomers,
unlike linearly 2,3-naphthalene-
condensation of 25 with 21 was conducted in boiling quino-
line in the presence of metal salts (NiCl2 or VCl3) or lithium
2-(dimethylamino)ethoxide (Scheme 3). The reaction of 25
and 21 in a 1:1.5 molar ratio with NiCl2 in quinoline at
2508C for 2 h led to a mixture of 1,2-NiNc and three new
compounds: 1,2-NiTNTAC (in 15% yield), 1,2-NiDNTABC
(0.9%), and 1,2-NiDNTAiBC (2.0%). The condensation
of these dinitriles in boiling quinoline for 6 h in the presence
of lithium 2-(dimethylamino)ethoxide resulted in a mixture
comprising 1,2-H2Nc as the major product and a small
amount of metal-free 1,2-TNTAC (2.1%). The desired
compounds, which contain quaternary carbon atoms with
methyl substituents, were easily separated from the less-
soluble 1,2-Nc by extraction of the crude product mixture
fused compounds, attempts were made to use 4-phenyl-1,2-
naphthalic anhydride (24) as the starting material, as phenyl
groups would give products with greater solubility in low-
polar organic solvents such as toluene or chloroform, there-
by facilitating the separation of pure isomers. Thus, com-
pound 24 was subjected to mixed condensation with 25 in
boiling sulfolane in the presence of NiCl2 and urea
(Scheme 3), although workup and column chromatography
gave no pure isomers; 1,2-NiTNPhTAC (14, 11%), 1,2-
NiDNPhTABC (15, 0.8%), and 1,2-NiDNPhTAiBC (16,
1.7%) were each separated as a mixture of isomers.
Unsubstituted nickel derivatives were used in this study
for the following spectroscopic and electrochemical investi-
gations.
Separation and structural char-
acterization of the isomers: Al-
though 1,2-NiDNTABC and
1,2-NiDNTAiBC are isomers,
they can be readily character-
ized by analysis of their absorp-
tion spectra since their spectral
band shapes are characteristic
of their molecular symmetries,
as described in our preceding
paper.[5] In addition, 1,2-NiDN-
TABC exists as a mixture of
two isomers (6 and 7), and simi-
larly 1,2-NiDNTAiBC and 1,2-
NiTNTAC exist as three (8, 9,
and 10) and four (2, 3, 4, and 5,
Scheme 1) isomers, respectively.
Each isomer of 1,2-NiDNTABC
and 1,2-NiDNTAiBC was com-
pletely separated by TLC and
Scheme 3.
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E. A. Luk’yanets, N. Kobayashi et al.
identified by their 1H NMR spectra. Separation of 1,2-
NiTNTAC was achieved by reversed-phase HPLC. The H
NMR data are summarized in Table 1.
To separate the isomers of 1,2-NiDNTABC, a mixture of
chloroform/hexane (1:4 v/v) was used as eluent, and each
TLC sheet was developed three times. Two pink fractions
with Rf =0.21 and 0.18 were isolated, then dissolved in
chloroform, filtered and the solvent evaporated. Figure 1
ent frequencies (d=1.69 and 1.72 ppm). These two isomers
were structurally assigned by performing NOE experiments
on the methyl signals, that is, a through-space interaction be-
tween the two split methyl signals allowed the structures of
the two isomers to be determined. As shown in Figure 2,
1
Figure 2. 1H NMR (top) and NOE (middle and bottom) spectra of a mix-
ture of 6 and 7. Irradiation frequencies were set at d=1.73 and 1.72 ppm
for the middle and bottom spectra, respectively.
NOE experiments were performed on a mixture of the two
isomers. When the lower-field signal (d=1.73 ppm, the first
fraction, 6) was irradiated, no meaningful NOE was ob-
served for the other signal in the region between d=1.67–
1.70 ppm. On the other hand, irradiation of the higher-field
signal (d=1.72 ppm, the second fraction, 7) generated a de-
tectable NOE (a positive peak at dꢀ1.69 ppm), which indi-
cates that this signal comes from 7. Spectral integration indi-
cates that the mixture consists of approximately equal
amounts of 6 and 7.
Figure 1. 1H–1H COSY spectrum of 6 in [D8]toluene.
1
shows the H–1H COSY spectrum of 6. The doublet signals
at d=10.69 and 9.04 ppm have been reasonably assigned to
protons a and f, respectively[11] (see inset in Scheme 1). By
taking through-bond interactions into consideration, the sig-
nals at d=7.85, 7.52, 7.94, and 7.98 ppm can be assigned to
protons b, c, d, and e, respectively. Split methyl proton sig-
nals appear at d=1.68 and 1.73 ppm. The 1H NMR spec-
trum of 7 is almost identical to that of 6 in the aromatic
region, although the methyl protons appear at slightly differ-
The three isomers of 1,2-NiDNTAiBC (Rf =0.31, 0.27,
and 0.18) were similarly separated by TLC by using chloro-
form/hexane (2:3 v/v) as eluent. The isomer ratio was esti-
mated to be approximately 8:1:14 for the first to third frac-
tions, which have been attributed to 8, 9, and 10, respective-
ly, on the basis of their 1H NMR spectra (Figure 3). The
second and third fractions evidently have only one type of
proton for each position on the fused-naphthalene, which in-
Table 1. 1H NMR (400 MHz) data of the isomers of 1,2-NiTNTAC, 1,2-NiDNTABC, and 1,2-NiDNTAiBC in [D8]toluene.
Compd
d [ppm]
1,2-NiTNTAC
2
10.99 (br, 1H), 10.73 (d, 2H), 9.25 (br, 3H), 8.12–7.81 (m, 9H), 7.57–7.53 (m, 3H), 1.83 (s, 12H)
3
4
5
11.05 (d, 2H), 10.76 (d, 1H), 9.40–9.34 (m, 2H), 9.09 (d, 1H), 8.15–7.98 (m, 9H), 7.60–7.57 (m, 3H), 1.80 (s, 6H), 1.77 (s, 6H)
10.90–10.87 (m, 2H), 10.68 (d, 1H), 9.13–9.07 (m, 3H), 8.07–7.84 (m, 9H), 7.62 (t, 1H), 7.53 (t, 2H), 1.82 (s, 6H), 1.79 (s, 6H)
10.93 (d, 3H), 9.27 (d, 1H), 9.09 (d, 1H), 9.03 (d, 1H), 8.07–7.93 (m, 9H), 7.64–7.55 (m, 3H), 1.77 (s, 12H)
1,2-NiDNTABC
6
7
10.69 (d, 2H), 9.04 (d, 2H), 7.99–7.93 (m, 4H), 7.85 (t, 2H), 7.52 (t, 2H), 1.73 (s, 12H), 1.68 (s, 12H)
10.71 (d, 2H), 9.05 (d, 2H), 7.99–7.95 (m, 4H), 7.85 (t, 2H), 7.52 (t, 2H), 1.72 (s, 12H), 1.69 (s, 12H)
1,2-NiDNTAiBC
8
10.84 (d, 1H), 10.49 (d, 1H), 9.14 (d, 1H), 8.85 (d, 1H), 7.99–7.80 (m, 6H), 7.55–7.48 (m, 2H), 1.55 (s, 6H), 1.50 (s, 6H), 1.40 (s, 6H),
1.39 (s, 6H)
9
10
10.81 (d, 2H), 8.88 (d, 2H), 7.98–7.90 (m, 6H), 7.59–7.55 (m, 2H), 1.50 (s, 12H), 1.39 (s, 12H)
10.48 (d, 2H), 9.10 (d, 2H), 7.98–7.93 (m, 4H), 7.81 (t, 2H), 7.50 (t, 2H), 1.55 (s, 12H), 1.40 (s, 12H)
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1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
96:76:100:65 in the order of
elution.[15] Since the statistically
expected yield is equivalent for
all the isomers, unlike the 2,3-
tetrasubstituted Pcs discussed
by Hanack co-workers,[16] the
relatively low yield of the
second and fourth fractions sug-
gests that sterically hindered
local structures are present, as
described above for the 1,2-
NiDNTAiBCs. From the 1H
NMR spectra (Figure 5) of the
fractions, each isomer of 1,2-
NiTNTAC can be clearly classi-
fied into two categories, that is,
the first and fourth fractions
and the second and third frac-
Figure 3. 1H NMR spectra of 8 (top), 9 (middle), and 10 (bottom) in [D8]toluene.
dicates the existence of a mirror plane perpendicular to the
molecular plane. On the other hand, the spectral shape of
the first fraction is an approximate superimposition of those
of the second and third fractions. Therefore, the structure of
the first fraction was unambiguously determined to be 8.
This also demonstrates that the resonance frequencies
depend greatly on the local structure of the molecule. In
other words, from the results of this experiment it can be
claimed that the half structure divided by the plane normal
to the molecular plane (i.e. the same as the mirror planes
Figure 4. Chromatogram for the separation of the mixture of 1,2-NiTN-
TACs.
for 9 or 10) determines the resonance frequencies, which in
turn means that the aromatic protons are not affected by
the other naphthalene ring, although the methyl signals are
sensitive to the orientation of the fused naphthalene rings.
Since the methyl resonances at approximately d=1.4 ppm
are less sensitive to the structure of the molecule than those
at approximately d=1.50–1.55 ppm, these resonances can be
assigned to a protons (see Scheme 1). The spectrum of the
second fraction shows a methyl resonance at a higher field
than that of the third fraction, which indicates that a smaller
loop-current effect is generated by the fused naphthalene
ring. Therefore, the structure of the second fraction was as-
signed to 9. In addition, it was shown that the ratio of the
isomers is related to steric hindrance, and the low yield of
the second fraction also implies its structure is 9 because a
non-negligible steric effect must exist between the two
naphthalene rings of 9 in order for skeletal deformation to
occur (details of this will be discussed in the subsequent sec-
tion).
Attempts were also made to separate each isomer of 1,2-
NiTNTAC by using TLC, although these were unsuccessful.
The complete separation of 1,2-NiTNTACs was achieved by
HPLC on an octadecyl-modified silica-gel column (Shinwa
Chemical Industries, Ltd.) by using chloroform/methanol
(2:3 v/v) as the solvent. A flow rate of 10 mLminꢁ1 gave the
best separation. According to the chromatogram shown in
Figure 4, the mixture consists of isomers in a ratio of
tions, depending on the methyl resonances. Since only one
type of methyl proton was observed for the first and fourth
fractions, their structures can be assigned to
2 or 5
(Scheme 1) because the local structure surrounding these
methyl groups is symmetric. In contrast, the spectra of the
second and third fractions exhibit two types of methyl
group, which indicates naphthalene rings fused in different
orientations. In order to distinguish the first and fourth frac-
tions, NOE experiments were performed by irradiating the
methyl resonances. As depicted in Figure 6, the first fraction
shows a detectable NOE for the proton a (d=10.9 ppm),
which is not observed for the fourth fraction, which implies
that the proton a of the first fraction is located closer to the
methyl groups than that of the fourth fraction. On the other
hand, the fourth fraction exhibits a NOE for the proton f
(dꢀ9.2 ppm). These considerations, as well as the low yield
of the fourth fraction, all support the conclusion that the
structure of the first fraction is 2, and therefore that of the
fourth fraction is 5. Unfortunately, the expected NOEs were
not observed for the second and third fractions probably be-
cause of the very low solubility of these compounds. We
concluded that the structures of the second and third frac-
tions are 3 and 4, respectively, on the basis of their forma-
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E. A. Luk’yanets, N. Kobayashi et al.
naphthalene from the mean
plane being 0.24 ꢁ.[12] It is con-
ceivable that the structural per-
turbations at the hydrogenated
sites propagate to the naphtha-
lene-fused sites to contact two
naphthalenes through the aro-
matic core skeleton.
IR spectroscopy: As described
in our preceding paper,[5] IR
spectra reflect well the molecu-
lar structures of the tetraaza-
chlorins and the DFT method
was found to reproduce the
characteristics of the spectra
reasonably well. In this study,
our interests focused, in partic-
ular, on whether or not each
isomer can be distinguished by
their IR spectra. The complexi-
ties of the IR spectra of the 1,2-
naphthalene-fused derivatives
Figure 5. 1H NMR spectra of 2, 3, 4, and 5 (from top to bottom) in [D8]toluene.
Figure 6. NOE spectra of 2 (top) and 5 (bottom) in [D8]toluene. Irradia-
tion was set at the methyl resonances.
tion ratio, although there is only circumstantial evidence for
these assignments.
Molecular modeling: As briefly described in the preceding
section, steric repulsion between the local structures of
these molecules could possibly affect the yield of each
isomer. Figure 7 depicts as examples the top and side views
of the computationally optimized [DFT/6-31G(d)] structures
of 9 (left) and 10 (right). The long axes of the two fused
naphthalene moieties of 9 point inwards so that the two
naphthalene rings may contact each other, while those of 10
point outwards. The calculations revealed that van der Waals
contacts exist between the two a protons of 9 (Ha–Ha dis-
tance, 2.07 ꢁ). On the other hand, this type of steric repul-
sion was not evident in 10, in which the Hf–Hf distance was
about 3.88 ꢁ. Hence, deformation from planarity was de-
tected for 9 as shown in the side view, although the p-conju-
gation plane of 10 is almost planar. Interestingly, the corre-
sponding C2v-symmetric 1,2-Nc has been reported as being
practically planar, with the maximum deviation of the fused
Figure 7. Optimized structures of 9 (left) and 10 (right). Top view (top)
and side view (bottom) are depicted by space-filling, and ball-and-stick
models, respectively.
are comparable to those of the corresponding 2,3-naphtha-
lene-fused derivatives since both have the same number of
vibrational freedoms. Both experimental and calculated re-
sults for the 1,2-NiDNTABCs (6 and 7) and the 1,2-NiTN-
TACs (2–5) are supplied in the supporting information. Al-
though the experimental IR spectrum of 1,2-NiTNTAC was
obtained for only a mixture of the four isomers owing to dif-
ficulties in preparative-scale separation, the calculations
show only small differences from species to species, except
for a band that appears at about 1200 cmꢁ1. Similarly, the
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1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
calculated frequencies for the different 1,2-NiDNTABCs are
very similar. Nevertheless, in the latter case, there are
minute differences between the calculations and the experi-
mental spectra. For example, two frequencies were calculat-
ed at 1208 and 1196 cmꢁ1 (energy difference, 14 cmꢁ1) for 6,
and the corresponding modes were estimated to be at 1203
and 1195 cmꢁ1 (8 cmꢁ1) for 7. Experimentally, these bands
were detected at 1222 and 1208 cmꢁ1 (14 cmꢁ1) for 6 and
1211 and 1201 cmꢁ1 (10 cmꢁ1) for 7. Similarly, the calculated
frequencies at 1021 and 1015 cmꢁ1 (6 cmꢁ1) for 6 shifted to
1028 and 1015 cmꢁ1 (13 cmꢁ1) for 7, reproducing the experi-
mentally observed spectra reasonably well [1033 and
1025 cmꢁ1 (8 cmꢁ1) and 1038 and 1021 cmꢁ1 (17 cmꢁ1) for 6
and 7, respectively]. Figure 8 (right) shows the calculated
and experimental IR spectra of each fraction of the 1,2-
NiDNTAiBCs. Unlike the other derivatives, the spectra of
the different isomers are clearly distinguishable from each
other. The spectra of all the isomers show a very intense
band at approximately 1530 cmꢁ1, which can be ascribed to
in-plane skeletal motion, including marked displacement of
the meso-nitrogen atoms (Figure 9, bottom). Medium inten-
sity bands observed in the spectra of 8 and 10 at about
1090 cmꢁ1 appeared as a less intense band in the spectrum
of 9 at almost the same wavenumber (Figure 8, right-hand
side, and Figure 9, top). Hence, the calculations closely re-
produce the experimental observations, lending support to
our structural assignments based on the NMR spectra. Most
of the spectral features are similar to those of the corre-
sponding benzene- or 2,3-naphthalene-fused derivatives: 1)
Out-of-plane motion of the fused aromatics appear in the
energy region below 1000 cmꢁ1, although their intensity is
low. 2) Modes assigned to in-plane motion of the peripheral
hydrogen atoms are spread over the whole spectral region.
3) The vibrational modes localized within the inner 18-p
system were rarely recognized and were of low intensity.
Electronic absorption and MCD spectroscopy: Figure 10
shows the absorption and MCD spectra of all the com-
pounds in this study. Optical data and the band-fitting pa-
rameters of the Q-bands are summarized in Table 2 and
Table 3, respectively. The spectral features of these mole-
cules resemble those of the corresponding benzene- or 2,3-
naphthalene-fused derivatives.[5] Of the split Q-band of the
1,2-NiTNTACs (left-hand side) and the 1,2-NiDNTABCs
(center), the band at the longer wavelength was more in-
tense, and the splitting energies of the bands of the 1,2-
NiDNTABCs were larger. While the Q-band of the 1,2-
NiDNTAiBCs (right-hand side) was sharper for the longer
wavelength component, the shorter wavelength component
was submerged in the adjacent vibronic and hot bands. Each
isomer of the 1,2-NiTNTACs and 1,2-NiDNTABCs had an
essentially identical Q-spectral envelope, but this was not
the case for the 1,2-NiDNTAiBCs.
For the 1,2-NiTNTACs (2–5, Figure 10, left-hand side),
the splitting energy of the Q-band is approximately 3240–
3360 cmꢁ1, with the shorter wavelength component posi-
tioned at 596–599 nm, and the longer wavelength compo-
nent at 743–745 nm. This feature resembles the correspond-
ing benzene-fused derivative more than the isomeric 2,3-
naphthalene-fused derivative. According to the Pariser–
Parr–Pople (PPP) calculations reported previously, the fron-
tier-orbital energies of 1,2-naphthalocyanines are closer to
those of phthalocyanines than 2,3-naphthalocyanines,[17] and
the above observations indeed confirm that this also holds
for the TACs. The intensity ratios of the absorption and
MCD split Q-bands are approximately 2.6 (=7.97/3.01) and
ꢁ0.78 (=ꢁ5.94/7.66), based on the D0 and B0 values, respec-
tively (Table 3), which means that the longer wavelength
MCD Q-band is less intense because it is energetically (and
therefore magnetically) isolated from the other bands. The
B0/D0 values also demonstrate this trend. Some slight struc-
tural dependencies are observed in the 300–500 nm region.
For example, 2 has a medium intensity MCD trough at
about 380 nm, which is not seen in the other spectra. These
spectral characteristics are nicely predicted by the molecu-
lar-orbital calculations described in the following section.
The Q-band of the 1,2-NiDNTABCs (6 and 7, Figure 10,
center) can be assigned by utilizing the MCD spectra. The
1,2-NiDNTABCs show large Q-band splitting energies of
approximately 8120 cmꢁ1, which is much larger than those
Figure 8. Experimental (solid lines) and calculated (bars) IR spectra of
1,2-NiTNTAC (left, top), 6 (left, bottom), and three isomers of 1,2-
NiDNTAiBCs (8, 9, and 10 from top to bottom, respectively).
Chem. Eur. J. 2005, 11, 1235 – 1250
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E. A. Luk’yanets, N. Kobayashi et al.
B term, the other coupled Q-
band, which must have the op-
posite MCD sign,[19,20] should
appear in
a
higher energy
region. Figure 11 shows the re-
sults of the band-deconvolution
analysis of 8. The Q00-band
component at the longer wave-
length is readily assigned as the
band at 680 nm. However,
there is some ambiguity for the
other coupled Q00-band compo-
nent at higher energy. In gener-
al,
metallophthalocyanines
(MPcs) show vibronic progres-
sion bands to a higher energy
of the Q00-band (the so-called
Q01-band). The energy separa-
tion between the Q00- and Q01-
bands in normal MPcs with D4h
symmetry is considered to be
approximately 1.1 kcmꢁ1 and
this also holds for MPc deriva-
tives with other symmetries.[21]
Therefore, we assigned the
band at 625 nm as the Q01-band
of the Q00-band at 680 nm
(energy separation 1.29 kcmꢁ1)
and the band deconvoluted at
604 nm as the other Q00-band.
As described later, molecular
orbital calculations, particularly
the estimated energy separation
of about 1970 cmꢁ1 from the
Figure 9. Atomic movements at the selected predicted frequencies.
lower Q00-band, also support
this assignment (the energy sep-
observed for dibenzene- (ca. 6700 cmꢁ1) or 2,3-dinaphtha-
lene-fused TABCs (ca. 4300 cmꢁ1).[5] Hence, to the best of
our knowledge, the 1,2-NiDNTABCs have the second larg-
est Q-band splitting energy of all the Pc derivatives known
to date,[18] behind tetraazabacteriochlorin (ca. 9000 cmꢁ1).[3a]
The energy of the shorter wavelength component (513 nm)
is similar to that of the benzene-fused derivative (538 nm)
and the longer wavelength component (ca. 880 nm) lies be-
tween those of the benzene- (842 nm) and 2,3-naphthalene-
fused derivatives (892 nm). Because of the large energy
splitting of the Q-band, the MCD intensity of the longer
wavelength component is very low. Band-deconvolution
analysis estimated the B0/D0 value of the longer wavelength
component to be ꢁ0.12 (Table 3), which is significantly
lower than the values for the other derivatives. The spectral
shapes of the two isomers are practically identical, except
for slight differences in the 300–400 nm region.
aration between the Q00-bands at 681 and 604 nm was deter-
mined experimentally to be ca. 1850 cmꢁ1). Although the Q-
band at the longest wavelength shifts from 675 to 689 nm
depending on the isomer, the spectral envelopes of isomers
8 and 9 were very similar in shape.
Electrochemistry and molecular orbital calculations:
Figure 12 displays the cyclic and differential pulse voltam-
mograms of nickel complexes in o-DCB containing 0.1
moldmꢁ3 tetrabutylammonium perchlorate (TBAP); the ex-
perimental redox potentials are listed in Table 4 and
Figure 13. The electrochemical data were obtained for mix-
tures of isomers. The second oxidation potentials were diffi-
cult to read directly from the CV curves because of the in-
stability of the second oxidation products. Although this fea-
ture is similar to that previously reported for Nc deriva-
tives[18b,22–24] and 2,3-naphthalene-fused hydrogenated deriva-
tives,[5] this redox behavior resembles that of the benzene-
fused derivatives of our preceding paper more closely.[5] All
of the couples have been assigned to ring-oxidation or ring-
reduction processes. The first oxidation and reduction cou-
Unlike the other derivatives, the 1,2-DNTAiBCs (8–10,
Figure 10, right-hand side) show marked differences in their
Q-band positions depending on the species. Since the MCD
signal that corresponds to the longest Q-band is the Faraday
1242
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1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
Figure 10. MCD (top) and absorption (bottom) spectra of 2–5 (left-hand side), 6 and 7 (middle), and 8–10 (right-hand side) in chlorobenzene.
ples were reversible for all the compounds. The first reduc-
tion potentials of 1,2-NiTNTAC and 1,2-NiDNTABC are
similar (ꢁ1.31ꢂ0.03 V), while that of 1,2-NiDNTAiBC was
more negative (ꢁ1.64 V). The first oxidation potentials
depend on the species; 1,2-NiDNTABC is the most prone to
oxidation (ꢁ0.02 V). The potential difference, DE, between
the first oxidation and reduction couples correlates with the
HOMO–LUMO energy gaps. DE decreases in the order 1,2-
NiDNTAiBC (1.70 V)>1,2-NiTNTAC (1.64 V)>1,2-NiDN-
TABC (1.26 V), in accordance with the order of the Q-band
energies, that is, the longer wavelength Q-band shifts to the
red in this order.
Molecular orbitals, transition energies, and oscillator
strengths (f) were calculated by using the ZINDO/S Hamil-
tonian. The geometries used for the calculations were those
obtained by the DFT calculations. Partial MO energy dia-
grams are shown in Figure 14 with calculated transition en-
ergies and oscillator strengths summarized in Figure 15 and
Table 5. Similarly to the benzene- or 2,3-naphthalene-fused
derivatives,[5] the Q-bands are dominated by the HOMO!
LUMO (or LUMO+1) transitions because of the large
energy gaps between the HOMOs and HOMOꢁ1s. In the
case of the TACs (i.e. 2–4), the HOMO, LUMO, and
LUMO+1 energies are very similar for the four isomers, so
that the calculated Q-band energies are approximately the
same. Slight differences seen in the energy region below the
HOMOꢁ2 and above the LUMO+3 give rise to the calcu-
lated spectral differences in the region around 400 nm. Com-
parison of the calculated results (Figure 15, left-hand side)
with the experimental data (Figure 10, left-hand side) re-
vealed that the splitting energy of the Q-band is reasonably
well reproduced, although the Q-band energies are estimat-
ed to be slightly lower. No significant difference in the in-
tensity ratio between the peaks of the split Q-bands was
seen, which is also consistent with the experimental data.
The two isomeric structures of the 1,2-NiDNTABCs are pre-
dicted to have identical Q-band spectra (Figure 15, middle),
almost in agreement with experimental observations
(Figure 10, middle). In the case of the 1,2-NiDNTAiBCs
(i.e. 8–10), the longest-wavelength Q-band appeared at dif-
ferent wavelengths depending on the isomers (Figure 10,
right-hand side), with the trend being nicely reproduced by
the molecular orbital calculations (Figure 15, right-hand
side). The lower energy Q-band component shifted to
Chem. Eur. J. 2005, 11, 1235 – 1250
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E. A. Luk’yanets, N. Kobayashi et al.
Table 2. Absorption and MCD spectral data for the 1,2-NiTNTACs, 1,2-NiDNTABCs, and 1,2-NiDNTAiBCs
in chlorobenzene.
the HOMOs, and ꢁ0.987,
ꢁ0.995, and ꢁ0.975 eV for the
LUMO+1s of 8, 9, and 10, re-
spectively). On the other hand,
the LUMO energy levels vary
depending on the structure
Compd
Absorption[a]
MCD[b]
1,2-NiTNTAC
2
302(0.37), 375(0.13)
444(0.05), 551(0.06)
596(0.38), 675(0.09)
745(0.46)
332(ꢁ0.14), 362(ꢁ0.12), 380(ꢁ0.10)
447(0.02), 595(1.66), 667(ꢁ0.16)
744(ꢁ0.56)
(ꢁ1.390,
ꢁ1.422 eV, in the same order).
As result, the largest
ꢁ1.356,
and
3
4
5
301(0.33), 352(0.13)
448(0.05), 551(0.05)
597(0.34), 675(0.09)
743(0.46)
304(0.33), 347(0.14)
378(0.09), 450(0.04)
548(0.05), 598(0.36)
673(0.09), 744(0.46)
303(0.32), 348(0.15)
377(0.08), 451(0.04)
553(0.04), 599(0.33)
670(0.08), 743(0.46)
329(ꢁ0.13), 352(ꢁ0.14), 446(0.02)
596(1.62), 667(ꢁ0.17), 742(ꢁ0.57)
a
HOMO–LUMO gap is calculat-
ed for 9 (4.132 eV) and the
smallest for 10 (4.070 eV). This
is, however, in contrast to the
calculated (and also experimen-
tally observed) spectra, that is,
the lowest- and the highest-
energy Q-bands were predicted
for 9 and 10, respectively. This
inconsistency can be resolved
by considering the configura-
tional interactions (CIs) be-
tween the HOMO!LUMO
346(ꢁ0.14), 448(0.02), 597(1.63)
670(ꢁ0.17), 743(ꢁ0.58)
307(0.05), 332(ꢁ0.14), 358(ꢁ0.12)
447(0.03), 598(1.55), 667(ꢁ0.17)
742(ꢁ0.57)
1,2-NiDNTABC
6
303(0.63), 329(0.28)
348(0.23), 478(0.08)
513(0.23), 783(0.17)
823(0.32), 879(0.87)
304(0.76), 330(0.33)
347(0.27), 473(0.09)
513(0.27), 780(0.19)
825(0.37), 880(0.87)
351(ꢁ0.14), 478(0.16), 513(0.58)
880(ꢁ0.20)
7
306(ꢁ0.17), 358(ꢁ0.16), 478(0.19)
512(ꢁ0.68), 785(ꢁ0.07), 880(ꢁ0.20)
and
HOMOꢁ1!LUMO+1
transitions. The HOMO and
LUMO+1 energies remain
almost constant, while the
LUMO energies change slightly
depending on the structure, so
that the LUMOꢁ1~LUMO+1
energy gaps become 6.476,
6.409, and 6.519 eV for 8, 9,
and 10, respectively, and the
energy differences between
1,2-NiDNTAiBC
8
297(0.57), 385(0.10)
569(0.15), 625(0.25)
653(0.25), 681(1.74)
299(0.75), 356(0.17)
569(0.22), 630(0.29)
660(0.28), 689(1.76)
307(0.38), 373(0.11)
569(0.13), 626(0.24)
649(0.26), 675(1.75)
307(ꢁ0.41), 354(ꢁ0.10), 440(ꢁ0.05)
463(ꢁ0.06), 569(0.78), 601(0.68)
625(0.50), 679(ꢁ2.52)
9
312(ꢁ0.41), 364(ꢁ0.08), 391(0.02)
461(ꢁ0.07), 572(0.88), 603(0.74)
626(0.40), 689(ꢁ2.51)
10
306(ꢁ0.33), 342(ꢁ0.09), 371(ꢁ0.06)
418(0.04), 467(ꢁ0.06), 570(0.72)
600(0.60), 624(0.58), 675(ꢁ2.68)
[a] l [nm] (10ꢁ5e [dm3 molꢁ1 cmꢁ1]). [b] l [nm] (10ꢁ5[q]M [degdm3 molꢁ1 cmꢁ1Tꢁ1]).
the
HOMO!LUMO
and
HOMOꢁ1!LUMO+1 transi-
tions are 2.371, 2.277, and
longer wavelengths in the order 10, 8, and 9, while the
higher-energy Q-band component showed the same trend in
both experiment and calculations. As shown in Figure 14,
the HOMO and LUMO+1 energy levels of the 1,2-NiDN-
TAiBCs are very similar (ꢁ5.495, ꢁ5.488, and ꢁ5.492 eV for
2.499 eV for 8, 9, and 10, respectively. Since larger CIs are
expected for the energetically closer transitions,[25] the larg-
est CI of the three isomers is expected for 9. Therefore, as a
result of CIs, the lower-energy Q-band appeared at the
lowest energy, even though the HOMO–LUMO gap is the
Table 3. Band-fitting parameters of the Q-bands.[a]
Compd
n [cmꢁ1
]
l [nm]
10ꢁ5emax
Dn [cmꢁ1
]
<e>0
D0
7.97
3.01
18.7
3.30
9.19
1.59
f
10ꢁ5 mCD int.
Band type
<eM
>
103B0
103(B0/D0)
0
2
13406
16798
11288
19509
14710
16565
14517
16484
14832
16611
746
595
886
513
680
604
689
607
674
602
0.46
0.37
0.99
0.22
1.47
0.11
1.65
0.12
1.54
0.08
710
414
657
901
282
715
310
777
252
567
2603
983
6123
1080
3003
518
3748
604
2795
287
0.15
0.07
0.30
0.09
0.19
0.04
0.24
0.04
0.18
0.02
ꢁ0.53
1.49
B
B
B
B
B
B
B
B
B
B
ꢁ0.91
1.17
ꢁ5.94
7.66
ꢁ0.74
2.54
6
8
ꢁ0.19
ꢁ0.35
ꢁ2.29
ꢁ0.12
0.51
0.77
5.02
1.52
ꢁ2.13
0.55
ꢁ1.32
0.77
ꢁ8.65
5.03
ꢁ0.94
3.17
9
11.5
ꢁ2.34
ꢁ1.61
ꢁ10.6
ꢁ0.92
1.85
8.56
0.88
0.54
0.83
5.43
2.94
10
ꢁ2.34
0.39
ꢁ1.28
0.43
ꢁ8.42
2.84
ꢁ0.98
3.23
[a] n: calculated band center energy; emax: extinction coefficient of the band center; Dn: bandwidth; <e>o: the zeroth moment of the absorption band
intensity; D0: dipole strength in Debye units, D0 =<e>0/326.6; f: oscillator strength; <eM >0: zeroth moment of the B terms; B0: Faraday terms, B0 =
<eM >0/152.5.
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1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
Table 4. Redox potential data (versus Fc+/Fc) in o-DCB containing 0.1m
TBAP.[a]
1
Couple
E = [V]
DEp [mV]
2
1,2-NiTNTAC
L(0)/L(ꢁ1)[b]
L(ꢁ1)/L(ꢁ2)
L(ꢁ2)/L(ꢁ3)
L(ꢁ3)/L(ꢁ4)
1,2-NiDNTABC
L(0)/L(ꢁ1)[b]
L(ꢁ1)/L(ꢁ2)
L(ꢁ2)/L(ꢁ3)
L(ꢁ3)/L(ꢁ4)
1,2-NiDNTAiBC
L(0)/L(ꢁ1)[b]
L(ꢁ1)/L(ꢁ2)
L(ꢁ2)/L(ꢁ3)
L(ꢁ3)/L(ꢁ4)
+0.75
+0.30
ꢁ1.34
ꢁ1.64
195
80
130
+0.35
ꢁ0.02
ꢁ1.28
ꢁ1.63
110
110
110
+0.35
+0.06
ꢁ1.64
ꢁ2.19
100
100
100
[a] DEp represents the potential differences between the cathodic and
anodic peak potentials at a sweep rate of 50 mVsꢁ1. L represents the
ligand. [b] Data from the differential pulse voltammograms.
Figure 11. Simultaneous band deconvolution analysis of the absorption
and MCD Q-bands of 8. Split Q00-bands are shown as shaded areas,
while the experimental curves are shown as solid lines.
Figure 13. Electrochemically obtained redox data for 1,2-naphthalene-
fused derivatives (solid marks), benzene-fused derivatives (open marks),
and 2,3-naphthalene-fused derivatives (double marks).
this interpretation. That is, the smallest coefficient for 9
means that the contribution of other one-electron transitions
is more significant for 9 (rather than 8 and 10), which results
in the stabilization of the lowest-energy transition state.
Figure 12. Cyclic voltammograms of 1,2-NiTNTAC (top), 1,2-NiDN-
TABC (middle), and 1,2-NiDNTAiBC (bottom) in o-DCB containing
0.1 molLꢁ1 TBAP. Sweep rate=50 mVsꢁ1. All measurements were made
using a mixture of isomers. Differential pulse voltammograms, in which
solid lines indicate cathodic scan and dashed lines anodic scan, are also
shown for the oxidation processes.
Conclusions
largest of the three. The coefficients of the HOMO!
LUMO transitions (0.6893, 0.6889, and 0.6900, for 8, 9, and
10, respectively) for the lowest-energy Q-band also support
A series of 1,2-naphthalene-ring-expanded hydrogenated
tetraazaporphyrin analogues, that is, 1,2-TNTACs, 1,2-
DNTABCs, and 1,2-DNTAiBCs, have been synthesized. The
Chem. Eur. J. 2005, 11, 1235 – 1250
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1245

E. A. Luk’yanets, N. Kobayashi et al.
Figure 14. Partial MO energy diagrams for all the possible isomers as calculated by the ZINDO/S method.
Figure 15. Calculated absorption spectra for 2–5 (left-hand side), 6 and 7 (middle), and 8–10 (right-hand side).
synthetic procedures have been carefully optimized to
obtain optimal results. All of the nine possible derivatives,
including four, two, and three structural isomers, of the 1,2-
NiTNTACs, 1,2-NiDNTABCs, and 1,2-NiDNTAiBCs, re-
spectively, have been successfully separated, and the struc-
tures of each isomer determined by using H NMR spectro-
1
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Chem. Eur. J. 2005, 11, 1235 – 1250

1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
Table 5. Calculated transition energies and oscillator strengths(f).
E [cmꢁ1
]
l [nm]
f
E [cmꢁ1
]
l [nm]
f
E [cmꢁ1
]
l [nm]
f
E [cmꢁ1
]
l [nm]
f
E [cmꢁ1
]
l [nm]
f
2
3
4
5
6
12607
16093
23381
23866
24913
25510
26925
27093
27556
27640
28637
29824
30906
31056
31447
32383
32895
793
621
428
419
401
392
371
369
363
362
349
335
323
322
318
309
304
1.05
0.79
0.06
0.09
0.03
0.16
0.02
0.32
0.02
0.31
0.07
0.03
0.11
0.12
0.54
0.22
0.15
12585
16072
23343
23552
24826
25510
26788
26896
27755
27894
28620
28935
29682
30012
31338
31888
32196
32669
33003
795
622
428
425
403
392
373
372
360
359
349
346
337
333
319
314
311
306
303
1.09
0.74
0.04
0.05
0.06
0.16
0.21
0.23
0.04
0.14
0.08
0.10
0.07
0.03
0.26
0.04
0.15
0.11
0.10
12618
16112
23364
23574
25151
25452
26788
27093
27322
27716
28329
30534
31182
31766
32289
32563
32798
793
621
428
424
398
393
373
369
366
361
353
328
321
315
310
307
305
1.11
0.73
0.03
0.07
0.05
0.13
0.21
0.18
0.25
0.01
0.16
0.16
0.26
0.06
0.05
0.09
0.32
12602
16082
23283
24826
25439
26589
26867
28337
28620
29240
29682
30535
30950
31857
32072
32616
794
622
430
403
393
376
372
353
349
342
337
328
323
314
312
307
1.09
0.67
0.03
0.11
0.09
0.25
0.24
0.21
0.04
0.12
0.03
0.04
0.06
0.04
0.07
0.02
11710
17908
22800
23441
24882
26302
28257
28910
31786
32425
854
558
439
427
402
380
354
346
315
308
1.72
0.30
0.02
0.01
0.23
0.08
0.03
0.02
0.27
0.03
7
8
9
10
11708
17928
22619
24975
25471
27801
30647
32175
854
557
442
400
393
360
326
311
1.73
0.31
0.01
0.25
0.07
0.06
0.06
0.04
14592
16567
24108
24988
26240
26448
27435
29104
30893
31153
31746
685
604
415
400
381
378
365
344
324
321
315
1.16
0.35
0.09
0.03
0.16
0.11
0.38
0.10
0.16
0.37
0.10
14499
16504
24033
24266
26116
26688
26838
28571
28744
31008
31319
31878
690
606
416
412
383
375
373
350
348
323
319
314
0.99
0.39
0.06
0.07
0.06
0.21
0.15
0.01
0.29
0.42
0.02
0.02
14689
16576
24673
24857
26254
26530
26638
27747
27894
31114
31666
32103
32992
681
603
405
402
381
380
375
360
359
321
316
312
303
1.33
0.32
0.03
0.09
0.11
0.26
0.01
0.39
0.07
0.59
0.05
0.01
0.07
scopy and molecular models. These compounds have been
characterized by various spectroscopic and electrochemical
methods, including absorption, MCD, and IR spectroscopies,
and cyclic voltammetry. The results of molecular-orbital cal-
culations were used in the analysis of these physicochemical
data. The main results are summarized as follows:
4) DFT calculations reproduced even the observed IR spec-
tral differences among, particularly, isobacteriochlorin
structural isomers, reasonably well.
5) The optical and electrochemical trends resembled those
of the corresponding benzene-fused derivatives rather
than the 2,3-naphthalene-fused derivatives.
6) ZINDO/S molecular orbital and configuration-interac-
tion calculations support the band assignments and
trends in the HOMO and LUMO energies determined
by the electrochemical method.
1) Synthetic procedures for the starting materials, that is,
derivatives of 1,2-naphthalenedicarboxylic acid, have
been reinvestigated and improved.
2) Metal complexes of the 1,2-TNTACs, 1,2-DNTABCs,
and 1,2-DNTAiBCs have been synthesized by mixed
condensation of 1,2-naphthalenedicarboxylic acid deriva-
tives and tetramethylsuccinonitrile in quinoline in the
presence of VCl3 or NiCl2.
7) The Q-band positions of the three 1,2-NiDNTAiBC iso-
mers are reasonably well explained by the configuration
interactions between the HOMO!LUMO and HOMO-
1!LUMO+1 transitions.
3) TLC and HPLC techniques were successfully used to
1
separate all of the isomers formed. H NMR spectrosco-
py combined with the NOE method was used to charac-
terize each isomer and, thus determine the structures of
the products. The formation ratio of each isomer was ra-
tionalized in terms of the intramolecular steric repulsion
effect, which is predicted by geometry optimizations at
the DFT level.
Experimental Section
1
Measurements and computational methods: Absorption, MCD, H NMR
(400 MHz), IR, and mass spectra, and cyclic voltammograms were ob-
tained by following the methods described in our preceding paper.[5] 1H
NMR (600 MHz) and NOE experiments were performed with a Bruker
Chem. Eur. J. 2005, 11, 1235 – 1250
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ꢀ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1247

E. A. Luk’yanets, N. Kobayashi et al.
AM-600 instrument using [D8]toluene as the solvent at room tempera-
ture.
10 mL and purified by column chromatography on neutral alumina with
toluene as eluent. Two fractions were separated and analyzed by TLC
and UV/Vis spectroscopy. The first blue fraction was a mixture of 1,2-
NiDNTABC and 1,2-NiDNTAiBC; the second blue-green fraction was
1,2-NiTNTAC (15 mg). Further separation of the first fraction by column
chromatography on neutral alumina using toluene/hexane (1:1 v/v) as
eluent gave two fractions with Rf =0.50 and 0.16. Chromatography of
each fraction on Bio-beads S-x1 (Biorad) with chloroform as eluent af-
forded the desired 1,2-NiDNTABC (12 mg, 0.9%) as a pink solid and
1,2-NiDNTAiBC (25 mg, 2.0%) as a blue solid. The chlorobenzene so-
lution was concentrated to about 10 mL and purified by column chroma-
tography on silica gel by using chloroform/hexane (1:1 v/v) as eluent. A
blue-green portion was collected, evaporated under reduced pressure,
and combined with a second fraction obtained after evaporation of the
toluene solution followed by precipitation by adding ethanol into a satu-
rated CHCl3 solution, to give the desired 1,2-NiTNTAC (140 mg, 15%
based on 1,2-dicyanonaphthalene). MS (FAB): m/z: 729 ([M++1] for 1,2-
NiTNTAC), 686 ([M+] for 1,2-NiDNTABC, FAB), 686 ([M+] for 1,2-
NiDNTAiBC, FAB); elemental analysis calcd (%) for C44H30N8Ni (1,2-
NiTNTAC): C 72.45, H 4.15, N 15.36; found: C 72.64, H 4.70, N 14.64; el-
emental analysis calcd (%) for C40H36N8Ni (1,2-NiDNTABC): C 69.89, H
5.28, N 16.30; found: C 69.88, H 5.68, N 15.43; elemental analysis calcd
for C40H36N8Ni (1,2-NiDNTAiBC): C 69.89, H 5.28, N 16.30; found: C
70.28, H 5.63, N 15.37.
Similarly, all of the computational calculations were performed in the
same manner as described in the preceding paper[5] by using the Gaussian
98 program,[26] though in this case, an NEC TX7/AzusA computing
system operated by Tohoku University Supercomputing System Informa-
tion Synergy Center was used.
Synthesis and separation: Tetramethylsuccinonitrile (25) was prepared
according to the method described in the literature.[27] 4-Phenyl-1,2-naph-
thalenedicarboxylic anhydride (24) was also obtained by the method de-
scribed in the literature[28] by condensation of 1,1-diphenylethylene (22)
with maleic anhydride (18), followed by dehydrogenation of the resulting
bis-adduct (23) using sulfur. 1,2-Naphthalenedicarboxylic imide (26) was
obtained as previously described[28] by heating 1,2-naphthalenedicarbox-
ylic anhydride (19) with urea.
Thin-layer chromatography (TLC) using Merck silica gel 60 F254 on alu-
minum sheets (10ꢂ10 cm) was used to separate the geometrical isomers
of 1,2-NiDNTABC and 1,2-NiDNTAiBC. High-performance liquid chro-
matography (HPLC) was used to isolate the four geometrical isomers of
1,2-NiTNTAC by using an ULTRON VX-ODS W-type column (250ꢂ
20 mm).
1,2-Naphthalenedicarboxylic anhydride (19): This compound was pre-
pared by modification of the published method.[13] A mixture of a-bro-
mostyrene (17) (7.05 g, 0.039 mol), 18 (11.3 g, 0.115 mol), and a small
amount of hydroquinone was stirred in boiling trichlorobenzene (10 mL)
for 3 h (Scheme 2). HBr evolved vigorously during the reaction. Charcoal
was then added and the mixture was refluxed for a further 2 h and then
filtered whilst still hot. After the mixture was cooled, the trichloroben-
zene filtrate was subjected to chromatography on a silica-gel column by
using hexane and then hexane/chloroform (1:1 (v/v)) as eluent, and a por-
tion with Rf =0.25 was collected. Recrystallization from benzene afforded
the desired anhydride (2.9 g; 38%), m.p. 1678C (lit.[13] 165–1678C).
Method b: A mixture of 25 (0.51 g, 3.7 mmol), 19 (0.5 g, 2.5 mmol), urea
(0.9 g, 15 mmol), anhydrous NiCl2 (0.48 g, 3.7 mmol), and a catalytic
amount of ammonium molybdate was stirred in sulfolane (10 mL) at
2508C for 1.5 h (Scheme 3). During the reaction, a mixture of 25 (ca.
0.2 g, 1.5 mmol) and urea (ca. 0.2 g, 3.3 mmol) was added every 0.5 h.
After cooling to room temperature, the reaction mixture was diluted with
water, the precipitate was filtered off and washed with hot water and
then hot 60% EtOH until the washings became colorless. Purification
and separation of the crude residue was performed according to the pro-
cedure given above (method a), to yield 1,2-NiTNTAC (93 mg, 15%),
1,2-NiDNTABC (10 mg, 1.2%), and 1,2-NiDNTAiBC (30 mg, 3.5%).
The spectral characteristics were identical to those obtained by the above
method.
1,2-Dicyanonaphthalene (21): The reaction was carried out according to
the procedure given above for the synthesis of 19, starting from 17 (5.9 g,
0.032 mol), fumaronitrile (20) (7.5 g, 0.096 mol) and a small amount of
hydroquinone (Scheme 2). The trichlorobenzene filtrate was subjected to
chromatography on silica gel by using hexane and then chloroform as
eluent, to give the desired dinitrile (1.5 g; 26%), m.p. 1908C (from alco-
hol, lit.[10] 1908C).
Method c: A mixture of 25 (0.51 g, 3.7 mmol), 26 (0.5 g, 2.5 mmol), urea
(0.6 g, 10 mmol), anhydrous NiCl2 (0.48 g, 3.7 mmol), and a catalytic
amount of ammonium molybdate was stirred in sulfolane (10 mL) at
2508C for 1 h (Scheme 3). A mixture of 25 (ca. 0.2 g, 1.5 mmol) and urea
(ca. 0.2 g, 3.3 mmol) was added, and the reaction continued for a further
1 h, with the temperature maintained at 2508C. After cooling to room
temperature, the reaction mixture was diluted with water, the precipitate
was filtered off and washed with hot water and then hot 60% EtOH
until the washings became colorless. The purification and separation of
the crude residue were performed according to the procedure given
above (method a) to yield 1,2-NiTNTAC (88 mg, 15%), 1,2-NiDNTABC
(7 mg, 0.8%), and 1,2-NiDNTAiBC (27 mg, 3.1%). The spectral charac-
teristics were identical to those obtained by method a.
b,b,b’,b’-Tetramethyltri-1,2-naphthotetraazachlorin (1,2-H2TNTAC, 1): A
mixture of 21 (0.67 g, 3.8 mmol), 25 (0.77 g, 5.65 mmol) and lithium 2-(di-
methylamino)ethoxide (0.8 g, 8.4 mmol) was stirred in quinoline (10 mL)
at 2508C for 6 h (Scheme 3). After cooling to room temperature, the re-
action mixture was diluted with 50% acetone (100 mL), a small amount
of 5% HCl was added prior to the appearance of a precipitate, and the
precipitate was filtered and washed with hot water and 50% acetone
until the washings were nearly colorless. After drying, the crude residue
was transferred to a Soxhlet apparatus and extracted with EtOH and
then chlorobenzene. The chlorobenzene solution was concentrated to
about 10 mL under reduced pressure and purified by chromatography on
a silica-gel column by using chloroform as eluent. The first green fraction
was collected to give, after evaporation of the solvent followed by precip-
itation with chloroform/ethanol of the desired compound (0.018 g, 2.1%
based on 1,2-dicyanonaphthalene). MS (FAB): m/z: 673 ([M++1]); ele-
mental analysis calcd (%) for C44H32N8·H2O: C 76.50, H 4.96, N 16.22;
found: C 77.02, H 5.25, N 15.30.
Vanadyl b,b,b’,b’-tetramethyltri-1,2-naphthotetraazachlorin (1,2-VOTN-
TAC, 11), vanadyl b,b,b’,b’-octamethyldi-1,2-naphthotetraazabacterio-
chlorin (1,2-VODNTABC, 12), and vanadyl b,b,b’,b’-octamethyldi-1,2-
naphthotetraazaisobacteriochlorin (1,2-VODNTAiBC, 13): The reaction
was performed as described above (method a) by using 25 (0.78 g,
5.7 mmol), 21 (0.67 g, 3.8 mmol), anhydrous VCl3 (0.65 g, 4.1 mmol), and
a catalytic amount of ammonium molybdate. The reaction mixture was
worked up by following method a. A toluene solution was evaporated to
about 10 mL and purified by column chromatography on neutral alumina
with toluene/hexane (1:2 v/v) as eluent. Two fractions were collected and
after chromatography of each fraction on Bio-beads S-x1 (Biorad) with
chloroform as eluent, the desired 1,2-VODNTABC (26 mg, 2.0%) and
1,2-VODNTAiBC (20 mg, 1.5%) were obtained as a lilac and blue solid,
respectively. Further elution with toluene afforded a third green fraction,
which was 1,2-VOTNTAC (25 mg). The chlorobenzene solution was con-
centrated to about 10 mL and purified by column chromatography on
silica gel by using chloroform/hexane (1:1 v/v) as eluent. A major green
portion was collected, evaporated under reduced pressure, combined
Nickel b,b,b’,b’-tetramethyltri-1,2-naphthotetraazachlorin (1,2-NiTNTAC,
2–5), nickel b,b,b’,b’-octamethyldi-1,2-naphthotetraazabacteriochlorin
(1,2-NiDNTABC, 6 and 7), and nickel b,b,b’,b’-octamethyldi-1,2-naphtho-
tetraazaisobacteriochlorin (1,2-NiDNTAiBC, 8–10).Method a: A mixture
of 25 (0.78 g, 5.7 mmol), 21 (0.67 g, 3.8 mmol), anhydrous NiCl2 (0.48 g,
3.8 mmol), and a catalytic amount of ammonium molybdate was stirred
in quinoline (5 mL) at 2508C for 2 h (Scheme 3). After cooling to room
temperature, the reaction mixture was diluted with 50% EtOH (50 mL),
the formed precipitate filtered off and washed with hot water and then
hot 60% EtOH until the washings were colorless. The crude residue was
transferred to a Soxhlet apparatus and extracted with toluene and then
with chlorobenzene. The toluene solution was evaporated to about
1248
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Chem. Eur. J. 2005, 11, 1235 – 1250

1,2-Naphthalene-Ring-Fused Tetraazachlorins
FULL PAPER
with the third fraction obtained after evaporation of the toluene solution,
followed by precipitation with chloroform/ethanol, to give the desired
1,2-VOTNTAC (148 mg; 16% based on 21). MS (FAB): m/z: 738 ([M+
+1] for 1,2-VOTNTAC), 695 ([M+] for 1,2-VODNTABC, FAB), 695
([M+] for 1,2-VODNTAiBC, FAB); elemental analysis calcd (%) for
C44H30N8VO (1,2-VOTNTAC): C 71.64, H 4.10, N 15.19; found: C 71.56,
H 4.59, N 14.55; elemental analysis calcd (%) for C40H36N8VO (1,2-
VODNTABC): C 69.06, H 5.22, N 16.11%; found: C 68.61, H 5.46, N
15.75; elemental analysis calcd (%) for C40H36N8VO (1,2-VODNTAiBC):
C 69.06, H 5.22, N 16.11; found: C 69.30, H 5.48, N 15.46.
[6] E. A. Makarova, N. Kobayashi, E. A. Luk’yanets, Abtsr. 2nd Int.
Conf. on Porphyrins and Phthalocyanines 2002, Kyoto, Japan,
P496.
[7] E. F. Bradbook, R. P. Linstead, J. Chem. Soc. 1936, 1744.
[8] M. Hanack, G. Renz, J. Strꢃhle, S. Schmid, Chem. Ber. 1988, 121,
1479.
[9] M. Hanack, G. Renz, J. Strꢃhle, S. Schmid, J. Org. Chem. 1991, 56,
3501.
[10] V. M. Negrimovskii, M. Bouvet, E. A. Luk’yanets, J. Simon, J. Por-
phyrins Phthalocyanines 2000, 4, 248.
[11] E. H. Gacho, Ph.D. Thesis, Hokkaido University, 2001.
[12] E. H. Gacho, T. Naito, T. Inabe, T. Fukuda, N. Kobayashi, Chem.
Lett. 2001, 260.
[13] M. S. Newman, B. Dhawan, M. M. Hashem, V. K. Khanna, J. M.
Springer, J. Org. Chem. 1976, 41, 3925.
[14] F. Bergmann, J. Szmuszkowicz, G. Fawaz, J. Am. Chem. Soc. 1947,
69, 1773.
[15] To correct the dispersion of the molar absorption coefficient (e) at
720 nm for each isomer, evaluated areas in Figure 4 divided by e
were employed as the formation ratio.
[16] G. Schmid, M. Sommerauer, M. Geyer, M. Hanack in Phthalocya-
nines-Properties and Applications, Vol. 4 (Eds.: C. C. Leznoff,
A. B. P. Lever), VCH, New York, 1996, Chapter 1 .
[17] N. Kobayashi, H. Konami in Phthalocyanine-Properties and Applica-
tions, Vol. 4 (Eds.: C. C. Leznoff, A. B. P. Lever), VCH, New York,
1996, Chapter 9.
[18] For examples of metalloPcs showing split Q bands, see: a) N. Ko-
bayashi, T. Ashida, T. Osa, Chem. Lett. 1992, 1567; b) N. Kobayashi,
T. Fukuda, J. Am. Chem. Soc. 2002, 124, 8021; c) N. Kobayashi, H.
Miwa, V. N. Nemykin, J. Am. Chem. Soc. 2002, 124, 8007; d) R. W.
Begland, D. R. Hartter, F. N. Jones, D. J. Sam, W. A. Sheppard,
O. W. Webster, F. J. Weigert, J. Org. Chem. 1974, 39, 2341; e) A. G.
Montalban, W. Jarrel, E. Riguet, Q. J. McCubbin, M. E. Anderson,
A. J. P. White, A. G. M. Barrett, B. M. Hoffman, J. Org. Chem. 2000,
65, 2472; f) T, P. Forsyth, D. B. G. Williams, A. G. Montalban, C. L.
Stern, A. G. M. Barrett, B. M. Hoffman, J. Org. Chem. 1998, 63, 331;
g) J. W. Sibert, T. F. Baumann, D. J. Williams, A. J. P. White,
A. G. M. Barrett, B. M. Hoffman, J. Am. Chem. Soc. 1996, 118,
10487; h) J. A. Elvidge, J. H. Golden, R. P. Linstead, J. Chem. Soc.
1957, 2466; i) Y. Ikeda, H. Konami, M. Hatano, K. Mochizuki,
Chem. Lett. 1992, 763; j) M. Aoudia, G. Cheng, V. O. Kennedy,
M. E. Kenney, M. A. J. Rodgers, J. Am. Chem. Soc. 1997, 119, 6029;
k) P. Margaron, R. Langlois, J. E. van Lier, S. Gaspard, J. Photo-
chem. Photobiol. B 1992, 14, 187; l) S. V. Kudrevich, H. Ali, J. E.
van Lier, J. Chem. Soc., Perkin Trans. 1 1994, 2767; m) U. Michelsen,
H. Kliesch, G. Schnurpfeil, A. K. Sobbi, D. Wçhrle, Photochem.
Photobiol. 1996, 64, 694; n) A. Weitemeyer, H. Kliesch, D. Wçhrle,
J. Org. Chem. 1995, 60, 4900.
Nickel b,b,b’,b’-tetramethyltri-1,2-(4-phenylnaphtho)tetraazachlorin (1,2-
NiTNPhTAC, 14), nickel b,b,b’,b’-octamethyldi-1,2-(4-phenylnaphtho)te-
traazabacteriochlorin (1,2-NiDNPhTABC, 15), and nickel b,b,b’,b’-octa-
methyldi-1,2-(4-phenylnaphtho)tetraazaisobacteriochlorin (1,2-NiDNPh-
TAiBC, 16): The reaction was performed as described above (method b),
starting from 25 (0.37 g, 2.7 mmol), 24 (0.50 g, 1.8 mmol) (Scheme 3), an-
hydrous NiCl2 (0.35 g, 2.7 mmol), urea (0.66 g, 11 mmol) and a catalytic
amount of ammonium molybdate (Scheme 2). After analogous work up,
the crude residue was transferred to a Soxhlet apparatus and extracted
with toluene. The toluene solution was evaporated to about 10 mL and
purified by column chromatography on neutral alumina by using first tol-
uene/hexane (1:1, v/v) and then by gradually increasing the content of
toluene as eluent. Three fractions were collected, and each fraction was
subjected to chromatography on Bio-beads S-x1 (Biorad) with chloro-
form as eluent. The first pink fraction afforded the desired 1,2-NiDNPh-
TABC (6 mg, 0.8%), the second blue fraction was 1,2-NiDNPhTAiBC
(13 mg, 1.7%), and the third blue-green fraction was 1,2-NiTNPhTAC
(64 mg, 11% based on 4-phenyl-1,2-naphthalenedicarboxylic anhydride).
MS (FAB): m/z: 957 ([M++1] for 1,2-NiTNPhTAC), 839 ([M++1] for 1,2-
NiDNPhTABC, FAB), 839 ([M++1] for 1,2-NiDNPhTAiBC, FAB); ele-
mental analysis calcd (%) for C62H42N8Ni (1,2-NiTNPhTAC): C 77.75, H
4.42, N 11.70; found: C 77.92, H 5.22, N 10.81; elemental analysis calcd
(%) for C52H44N8Ni (1,2-NiDNPhTABC): C 74.38, H 5.28, N 13.35; found:
C 74.89, H 5.21, N 13.31; elemental analysis calcd (%) for C52H44N8Ni
(1,2-NiDNPhTAiBC): C 74.38, H 5.28, N 13.35; found: C 74.44, H 5.46, N
13.16.
Acknowledgements
This research was partially supported by the Ministry of Education, Sci-
ence, Sports and Culture, Japan, a Grant-in-Aid for the COE project,
Giant Molecules and Complex Systems, 2004. E.L. and E.M. thank
Moscow City Government and the Ministry of Science and Technology
of Russia for financial support.
[19] A. Tajiri, J. Z. Winkler, Naturforsch. A 1983, 38, 1263.
[20] A. Kaito, T. Nozawa, T. Yamamoto, M. Hatano, Y. Orii, Chem.
Phys. Lett. 1977, 52, 154.
[21] N. Kobayashi, T. Fukuda, D. Leliꢄvre, Inorg. Chem. 2000, 39,
3632.
[22] N. Kobayashi, T. Ishizaki, K. Ishii, H. Konami, J. Am. Chem. Soc.
1999, 121, 9096.
[23] N. Kobayashi, Y. Higashi, T. Osa, Chem. Lett. 1994, 1813.
[24] N. Kobayashi, R. Kondo, S. Nakajima, T. Osa, J. Am. Chem. Soc.
1990, 112, 9640.
[1] a) Phthalocyanines-Properties and Applications, Vols. I–IV (Eds.:
C. C. Leznoff, A. B. P. Lever), VCH, New York, 1989, 1993, 1993,
1996; b) Phthalocyanines-Chemistry and Functions (Eds.: H. Shirai,
N. Kobayashi), IPC, Tokyo, 1997 (in Japanese).
[2] a) Porphyrins and Metalloporphyrins (Ed.: K. M. Smith), Elsevier,
Amsterdam, 1975; b) The Porphyrins, Vols. 1–7 (Ed.: D. Dolphin),
Academic Press, New York, 1978; c) The Porphyrin Handbook,
Vols. 1–20 (Eds.: K. M. Kadish, K. M. Smith, R. Guilard), Academic
Press, New York, 1999, 2003.
[3] a) H. Miwa, E. A. Makarova, K. Ishii, E. A. Luk’yanets, N. Kobaya-
shi, Chem. Eur. J. 2002, 8, 1082; b) E. A. Makarova, G. V. Korolyo-
va, E. A. Luk’yanets, Zh. Obshch. Khim. 2001, 71, 874; c) E. A. Ma-
karova, G. V. Korolyova, E. A. Luk’yanets, Russian Patent, 2188200,
2000.
[4] a) E. A. Makarova, G. V. Korolyova, E. A. Luk’yanets, Abstr. 1st Int.
Conf. on Porphyrins and Phthalocyanines 2000, Dijon, France, P482;
b) T. Fukuda, E. A. Makarova, E. A. Luk’yanets, N. Kobayashi,
Abstr. 2nd Int. Conf. on Porphyrins and Phthalocyanines 2002,
Kyoto, Japan, P292.
[25] For example, see: M. Gouterman, H. Wagniꢄre, L. C. Snyder, J.
Mol. Spectrosc. 1963, 11, 108.
[26] Gaussian 98, Revision A.11.3, M. J. Frisch, G. W. Trucks, H. B.
Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, V. G. Zakr-
zewski, J. A. Montgomery, Jr., R. E. Stratmann, J. C. Burant, S. Dap-
prich, J. M. Millam, A. D. Daniels, K. N. Kudin, M. C. Strain, O.
Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C.
Pomelli, C. Adamo, S. Clifford, J. Ochterski, G. A. Petersson, P. Y.
Ayala, Q. Cui, K. Morokuma, N. Rega, P. Salvador, D. D. Dannen-
berg, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman,
J. Cioslowski, J. V. Ortiz, A. G. Baboul, B. B. Stefanov, G. Liu, A.
[5] T. Fukuda, E. A. Makarova, E. A. Luk’yanets, N. Kobayashi, Chem.
Eur. J. 2004, 10, 117.
Chem. Eur. J. 2005, 11, 1235 – 1250
www.chemeurj.org
ꢀ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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E. A. Luk’yanets, N. Kobayashi et al.
Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R. L. Martin,
D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara,
M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong,
J. L. Andres, C. Gonzalez, M. Head-Gordon, E. S. Replogle, J. A.
Pople, Gaussian, Inc., Pittsburgh, PA, 2002.
[27] W. Barbe, H.-D. Beckhaus, H.-J. Lindner, C. Rꢅchardt, Chem. Ber.
1983, 116, 1017.
[28] E. F. Bradbook, R. P Linstead, J. Chem. Soc. 1936, 1739.
Received: August 15, 2004
Published online: December 30, 2004
1250
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Chem. Eur. J. 2005, 11, 1235 – 1250